Next Article in Journal
Pyrrolizine- and Indolizine-Derived Spirooxindoles: Synthesis, Antibacterial Activity and Inverse Docking Analysis
Previous Article in Journal
Nuclear Magnetic Resonance Gas-Phase Studies of Spin-Spin Couplings in Molecules
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Chemistry
Volume 7
Issue 1
10.3390/chemistry7010017
chemistry-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Review

Noble Metal-Based Catalysts for Selective Oxidation of HMF to FDCA: Progress in Reaction Mechanism and Active Sites

by
Yingshuo Guo
,
Yitong Zhao
,
Shiao Gao
,
Binhong Lv
and
Zhijie Wu
*
State Key Laboratory of Heavy Oil Processing and the Key Laboratory of Catalysis of CNPC, China University of Petroleum, Beijing 102249, China
*
Author to whom correspondence should be addressed.
Chemistry 2025, 7(1), 17; https://doi.org/10.3390/chemistry7010017
Submission received: 26 December 2024 / Revised: 18 January 2025 / Accepted: 28 January 2025 / Published: 1 February 2025
(This article belongs to the Special Issue Catalytic Conversion of Biomass and Its Derivatives)
Browse Figures
Versions Notes

Abstract

:
5-hydroxymethylfurfural (HMF) is oxidized to 2,5-furandicarboxylic acid (FDCA), which serves as a sustainable alternative to the petrochemical derivative terephthalic acid as a polyester monomer. Currently, noble metal catalysts that combine high HMF conversion rates with FDCA selectivity have become one of the mainstream catalytic systems for HMF oxidation. This paper summarizes and discusses the research progress on HMF oxidation to FDCA over different noble metal-based catalysts by combining DFT theoretical calculations, introducing various reaction pathways and mechanisms of HMF oxidation. It also analyzes the characteristics and electronic properties of metal active sites, geometric effects, metal–support interactions, and confinement effects, discussing and revealing the roles and activation mechanisms of different metal active sites, the structure of catalysts, active substances, metal valence states, activity, and the relationship between metal and the oxidation of C=O and OH groups. Finally, it presents views on the challenges and future development in the design of noble metal-based catalysts.

1. Introduction

In recent years, driven by the widespread depletion of fossil resources and related environmental issues, abundant and renewable biomass has increasingly been used as a raw material for the production of biofuels, high-value biochemicals, and green materials (such as bioplastics) through sustainable bio-refining processes [1,2,3]. Currently, fuel or chemicals, such as ethanol [4,5], biodiesel [6,7], and furfural [8,9], synthesized from biomass have been industrially applied, significantly reducing dependence on fossil energy, which is of great significance for further carbon neutrality. Among them, the molecular structure of FDCA is similar to the petroleum-based monomer terephthalic acid (PTA) [10,11]. It can be polymerized with diols, diamines, or other monomers to produce polyethylene 2,5-furandicarboxylate (PEF). As an efficient and environmentally friendly bio-based plastic (Figure 1), it has superior degradability compared to traditional materials like polyethylene terephthalate (PET). Therefore, it has successfully replaced conventional the petroleum-based monomer PET and is expected to become a key bio-based polyester for developing environmentally friendly, biodegradable plastics and non-toxic plasticizers. Moreover, the U.S. Department of Energy also listed FDCA as one of the twelve most promising bio-based value-added platform chemicals in green chemical engineering in 2004 [12,13,14]. Thus, there is an urgent need to develop an efficient method for the product of FDCA, which not only brings significant economic benefits but also represents a fundamental path for circular sustainable development.
Currently, the synthetic pathways for FDCA mainly include furfural carboxylation [15,16], furan acylation [17,18], and HMF catalytic oxidation [19,20]. Among these, the selective oxidation of HMF to FDCA has shown high efficiency, simplicity, and environmental friendliness. Additionally, as one of the most promising multifunctional biomass molecules [21,22,23], HMF can be successfully converted into levulinic acid (LA), formic acid (FA), 2-hydroxymethylfuran (DHMF), and FDCA through internal structural reactions such as oxidation, polymerization, hydrogenation, and so on [24,25,26]. The continuous breakthroughs in HMF production technology and the gradual expansion of production capacity have significantly boosted the large-scale production and preparation of downstream high-value-added chemicals based on HMF as a raw material. Its oxidation products, FDCA, 2,5-dihydroxymethylfuran (HMFCA), 2,5-diformylfuran (DFF), and maleic acid (MA), are all important industrial products [27,28,29,30,31]. AVA Biochem was the first company in the world to commercialize HMF capable of achieving industrial production of high-purity HMF and its derivatives, with a production capacity of 5000–6000 tons per year. The direct oxidation method for synthesizing FDCA from HMF has become more feasible and necessary due to the commercialization of HMF. Therefore, developing efficient and low-cost HMF oxidation technology has become the key to addressing the current industrial preparation and commercial application of FDCA.
Different metal catalysts (noble and non-noble metals) and non-metal catalysts have been developed for the oxidation of HMF to prepare FDCA [32,33,34]. For non-noble metal catalysts, Gawade et al. [35] synthesized MnFe2O4 catalysts via a hydrothermal method to investigate the reaction performance of HMF oxidation for FDCA preparation. Under the conditions of 100 °C, 6 h, and tert-butyl hydroperoxide (TBHP) as the oxidant, the yield of FDCA could reach 85%. Yang et al. [12] prepared V/MoO3 nanorods with different crystal phases for HMF oxidation to FDCA by hydrothermal method and H2O2 treatment. Under the conditions of tert-butanol (TBA) and TBHP as oxidants, after 10 h, the V-MoO3 catalyst could achieve a conversion rate of HMF and a selectivity of FDCA up to 99.5% and 87.4%, respectively. However, the use of organic solvents such as TBA and TBHP can have a certain impact on the environment, which is not conducive to environmental protection. For non-metal catalysts, Verma et al. [36] prepared the chitosan-derived carbon nitride catalyst to HMF oxidation reactions under an oxygen atmosphere. It was found that after reacting for 36 h at 70 °C and atmospheric pressure, the yield of FDCA could reach 83%. Li et al. [37] used TEMPO catalysts and investigated HMF oxidation for FDCA preparation by adjusting the type of acid. It was found that after reacting for 48 h in the presence of phosphoric acid (H3PO4), the yield of FFCA could reach 83%. The results showed that the yield of FDCA significantly decreased after three cycles. This not only limits the potential for long-term application of the catalyst but also requires a long reaction time to achieve the best effect. However, compared with the above catalysts, noble metal catalysts do not require the addition of organic reagents as oxidants. Under an air or oxygen atmosphere and H2O as a solvent, they can quickly obtain a higher HMF conversion rate and FDCA yield. Moreover, after multiple cycles of reactions, noble metal catalysts can still maintain a high conversion rate and selectivity, avoiding catalyst deactivation, allowing for long-term use. A noble metal-based catalytic systems, such as platinum-based (Pt), gold-based (Au), and ruthenium-based (Ru) catalysts, have shown excellent activity in HMF oxidation and are widely used. Wu et al. [38] prepared RuOx/MnOx-VC catalysts for HMF oxidation under alkali-free conditions and found the synergistic interaction between the MnOx-VC support and Ru metal, in which oxygen vacancies of metal oxide enable efficient adsorption and anchoring of metal Ru, forming a highly dispersed Ru-O-Mn structure. At 120 °C and 1 MPa O2, the MnOx-VC catalyst can achieve 100% conversion of HMF and a 99% yield of FDCA after 4 h. Zhao et al. [39] prepared an Ag/-CeO2-DTPA-400 catalyst for the oxidation of HMF to FDCA. The interface formed between the metal Ag and the carrier CeO2 facilitates the transfer and separation of electrons, which can promote the activation of HMF and its intermediates. Under room temperature and an O2 atmosphere, the selectivity of FDCA can reach as high as 98% after 6 h. Cavallo et al. [40] successfully prepared dendritic and shell-structured Au-Co nano-catalysts for the oxidation of HMF to FDCA by controlling the concentration of Au and the addition method of the precursor. Compared with the shell-structured catalyst, the dendritic structure retains the Co core inside and has an open 3D structure with a higher specific surface area, which promotes electron transfer and thereby enhances activity.
Chemistry 07 00017 g001
Figure 1. (a) Classical process for the production of unrenewable plastics via fossil-based PTA and (b) a potential alternative pathway starting from a renewable feedstock [41].
Figure 1. (a) Classical process for the production of unrenewable plastics via fossil-based PTA and (b) a potential alternative pathway starting from a renewable feedstock [41].
Chemistry 07 00017 g001

2. Reaction Mechanism

The synthetic routes for the preparation method of FDCA have been widely proposed, involving the HMF oxidation pathway, furan acylation pathway, furfural disproportionation pathway, and di-glycol pathway (Figure 2) [42,43,44]. Among them, the di-glycol route is not environmentally sustainable, the furfural disproportionation route involves a complex process and low product yield, and the furan acylation requires many more reaction steps and yields low economic benefits. Instead, the HMF oxidation route has a wide range of raw material sources and a simple reaction process, which is green and environmentally friendly, showing good prospects for development, and is expected to achieve industrial production. Due to the difference in the oxidation sequence of the functional groups in HMF under acidic and alkaline environments, the oxidation of HMF to produce FDCA can currently proceed along two pathways: the DFF oxidation pathway (acidic environment) and the HMFCA oxidation pathway (alkaline environment). In the DFF pathway, the OH group in HMF is first oxidized to the C=O group, generating DFF. Then, the C=O group in DFF is further oxidized to the COOH group, forming the intermediate product FFCA. In contrast, in the HMFCA pathway, the C=O group in HMF becomes the preferred target for oxidation. The C=O group in HMF is oxidized to the COOH group, forming HMFCA, and then the OH group in HMFCA is further oxidized to the C=O group, generating FFCA. Finally, FFCA produced from both pathways undergoes successive oxidation to yield the target product FDCA (Figure 2).

2.1. Oxidation in Alkaline Solution via HMFCA Pathway

Reaction of HMF under alkaline conditions favors the oxidation of C=O bond and reduces the occurrence of side reactions, thereby improving the selectivity of FDCA. Liu et al. [46] prepared AumPdn/TiO2-xCA@HNTs catalyst and proposed a reaction mechanism for the oxidation of HMF to FDCA under alkaline solution, as shown in Figure 3a. The reaction process of HMF oxidation to FDCA mainly includes the following three stages: In Stage I (HMF→HMFCA), abundant OH− ions attack the C=O bond in HMF to generate an alkoxide ion intermediate, which is then dehydrogenated through the adsorbed AuPd nanoparticles (NPs) surface OH− to facilitate the formation of HMFCA. In Stage II (HMFCA→FFCA), the oxygen vacancies on the catalyst surface are activated and generate superoxide radicals O2−, which are beneficial to removed excess electrons deposited on the AuPd NPs and combined with H2O to generate a large amount of OH−. Subsequently, under the synergistic action of OH− ions and AuPd NPs, the O-H and C-H bonds on the side chain of the alcohol hydroxyl group in HMFCA are broken, leading to dehydration and the formation of FFCA. In Stage III (FFCA→FDCA), the C=O group on FFCA repeats the first stage process, and again under the oxidation action of AuPd NPs to produce FDCA. Furthermore, Lu et al. [47] have used Ni/NiOOH catalysts to similarly verify the oxidation mechanism of HMF under alkaline conditions, which is consistent with the oxidation pathway of HMF under alkaline conditions mentioned earlier for AumPdn/TiO₂-xCA@HNTs. Lu et al. validated the reaction mechanism for the oxidation of HMF to FDCA along HMFCA (Pathway A) and DFF (Pathway B) through density functional theory (DFT) theoretical calculations, as shown in Figure 3b. The activation energies for the generation of HMFCA* from HMF* through the TSA-1 intermediate transition state in Pathway A and the oxidation of FFCA* to FDCA* through the TS-3 transition state in Pathway B are 1.2 eV and 0.8 eV, respectively, with a higher activation energy barrier; thus, it is determined to be the rate-determine step from a thermodynamic perspective.
Beside the alkali condition via additional alkaline salts, the basic sites of catalysts can also promote reaction efficiency [48,49,50]. Zhang et al. [48] prepared AuPd/HB-ZrO2 catalysts for HMF oxidation under alkaline solution using added alkali salts at 100 °C and 2 MPa O2, achieved a 99.9% yield of FDCA. Without added alkali salts, Liao et al. [49] prepared an Au/Sn-Beta catalyst and found that a large number of OH− conduct nucleophilic attacks on the C=O group and transform into alkoxy intermediates, promoting the production of HMFCA intermediates. In addition, the Lewis acidic sites provided by isolated Sn4+ inside Sn-Beta zeolites can activate the OH and C=O groups in HMF, thereby increasing the catalytic yield of FDCA. The as-prepared Au/Sn-Beta catalyst achieved an FDCA yield of 98.0% under alkaline solution at 140 °C and 1 MPa O2. Wang et al. [50] studied the Mg-Al hydrotalcite supported Pd (Pd/HT) catalysts with different Mg/Al molar ratios for HMF oxidation to FDCA and found that the C=O group in the HMF can be attacked by OH− ions in hydrotalcite and dehydrogenated to generate the COOH group. The as-prepared Pd/HT, rich in basic sites, shows excellent oxidation efficiency with an FDCA yield >99.9%. Clearly, the addition of extra alkali salts is an efficient strategy to promote the catalytic oxidation efficiency for HMF oxidation via HMFCA routes, but the deactivation of active metal sites in alkaline solution is challenging [51]. Thus, developing green and environmentally friendly alkali-free routes for the catalytic oxidation of HMF to FDCA has attracted attention.

2.2. Oxidation Under Alkali-Free Conditions via DFF Pathway

Rao et al. [52] prepared a highly active Ru/Ni1Mn6 catalyst for the oxidation of HMF without added alkali salts and proposed a reaction mechanism for alkali-free oxidation, which is shown in Figure 4a. It involves the following three steps: In Path I (HMF→DFF), Ru metal sites adsorb and cleave the O-H bond in HMF in the form of RuO-(OH)x, forming a metal–alcohol oxide intermediate. Subsequently, dehydration of the metal alcoholate intermediate and β-H elimination form the C=O group, which produces DFF. In Path II (DFF→FFCA), the C=O group in DFF first combines with water to form a bis-alcohol intermediate. Under the action of O− and O2−, the Ru metal site is oxidized to RuO-(OH)x and combines with the bis-alcohol intermediate. After further dehydration and β-H elimination, the C=O group in DFF is oxidized to the COOH group, forming FFCA. In Path III (FFCA→FDCA), the other C=O group in FFCA repeats the oxidation process mentioned in the second step, ultimately producing the target product FDCA. In addition to the Ru-based catalyst, Pt- and-Pd based catalysts are also used in oxidation under alkali-free conditions. Cui et al. [53] prepared a porous carbon-supported PtPd catalyst and found that the introduction of Pd can regulate the electronic structure of Pt, promoting the formation of Pt0 species. Moreover, Pd0 and Pt0 active sites can promote the oxidation of the C=O and OH groups, respectively, and their synergistic effect improves the selectivity and yield of FDCA. At 90 °C the Pt0.5Pd0.5/NPC catalyst showed a high HMF conversion of 96.1% and an FDCA yield of 84.6%. Zhang et al. [54] synthesized a series of PtxRu-MgAlO catalysts with controllable particle sizes for the alkali-free oxidation of HMF to FDCA in an aqueous solution, realizing 100% conversion of HMF, with 99% FDCA selectivity at 100 °C and 0.2 MPa.
Meanwhile, Thara et al. [55] conducted a study on the reaction mechanism of HMF oxidation to FDCA on the β-MnO2 (110) crystal face, employing the Perdew–Burke–Ernzerhof (PBE) form of the generalized gradient approximation (GGA) functional, combined with ultra-soft pseudopotentials and the projector-augmented wave (PAW) method. The study integrated DFT with microkinetic models, as shown in Figure 4b. They proposed that HMF exists on the catalyst surface in the form of HMF* through Eley–Rideal or Langmuir–Hinshelwood mechanisms, and that HMF* can then be oxidized to FFCA* through two possible reaction pathways, A and B. Then, they oxidized to FDCA as the final product through Pathway C. For comparison, oxidation under alkaline conditions (Pathway A) was also discussed, in which the C=O group in HMF* was dissociated to generate a carboxylate intermediate and subsequently through the transition state TSA2 to form the intermediate HMFCA*. Then, the OH group of HMFCA* was further oxidized to the COOH group through the transition states TSA3 and TSA4, leading to the formation of FFCA*. Consequently, the sequential formation of FFCA from HMF via Pathway A is HMF→HMFCA→FFCA*. For the alkali-free conditions (Pathway B), the OH group in HMF prefers to undergo dissociation and generates DFF* through the TSB2 transition state. DFF* is further oxidized to FFCA* through the intermediate transition states TSB3 and TSB4, and the sequence of HMF oxidation in Pathway B is HMF*→DFF*→FFCA*. Finally, in Pathway C, the adsorbed FFCA molecules undergo rearrangement, eventually forming the FDCA and confirming the mechanism. The DFT calculation results clearly show that the construction of bifunctional or multifunctional sites for the activation of OH and C=O groups and the tandem conversion of HMF to FFCA should be effective in promoting oxidation efficiency under alkali-free conditions.

3. Structure–Activity Relationship of Noble Metal-Based Catalysts

The oxidation of HMF to FDCA is a structure-sensitive reaction where the interfacial interactions between components, the oxidation state of metals, geometric effects, and structural defects impact the adsorption and activation of HMF and other intermediates. Furthermore, strong interactions between the metal and the support can effectively promote the transfer of electrons between the metal and the support, thereby affecting the dispersion and valence state of the metal, generating a large number of active metal sites, and giving the catalyst higher HMF oxidation activity. Table 1 summarizes the performance of noble metal-based catalysts in the catalytic oxidation of HMF to FDCA under different reaction conditions in recent years. Under the synergistic effect of noble metal–support and the introduction of other supplements (such as alkali and rare earth metals), a high HMF conversion and FDCA selectivity can be achieved. For the alkali-free system, the Co@Nb-Pt catalyst shows the best reaction performance among many noble metal-based catalysts, with 100% conversion, >99% selectivity, and a 25 mol–1 h–1 product yield at 110 °C and 1 MPa O2 after 4 h of reaction.

3.1. Metal Active Sites

At present, Pt, Ru, Pd, and Au noble metals are frequently reported active sites for the oxidation of HMF to FDCA. These noble metal nanoparticles with abundant electrons can usually exhibit enhanced O2 activation ability by promoting the transfer of electrons from the 3D orbitals of metal nanoparticles to the antibonding π* orbitals of O2 [71,72]. Additionally, the accumulation of electrons on metal nanoparticles can to some extent prevent the oxidation of surface metal species, thereby enhancing the stability of the metal [73,74]. Therefore, increasing the charge density of active sites on metal particles can effectively improve the activity and stability of HMF oxidation to FDCA.
Zhang et al. [75] found that the number of Pt0 active sites in Pt/Nix catalysts could be controlled by changing the calcination temperature. High temperatures can promote electron transfer between metal Pt and Ni, increasing the surface binding energy of Pt0 and producing a large amount of adsorbed oxygen species (Oads), which is not conducive to the reaction. In contrast, the Pt/Ni25 catalyst prepared at low temperatures has the most electron-rich Pt0 species and lattice oxygen species (Olatt) on its surface, which can further stabilize Pt NPs in a reactive metallic state. The intrinsic activity of catalysts is found to be proportional to the fractions of Pt0 and Olatt species, as shown in Figure 5a; Pt0 sites are beneficial for the adsorption and activation of the C=O group in HMF and its intermediates. Fu et al. [76] prepared a CoOx-Ag/CeO2 catalyst for the oxidation of HMF. Experiments found that Ag+ acts as a key active site, accelerating the cleavage of the C-H bond in HMFCA to achieve dehydrogenation, thereby facilitating the transformation of HMFCA to FFCA. The doping of Ag promotes electron transfer between Ag and the support CeO2, generating a large number of Ag+ active sites while forming a stable Ag+-Ov-Ce3+ interface. This efficiently activates O2 and generates superoxide radicals, promoting the conversion of HMF. At the same time, the Ag+ active sites can synergistically interact with Ce3+ sites, significantly improving the yield of FDCA. Under the optimal reaction conditions, the yield of FDCA can reach 92.8%. Zhang et al. [77] prepared a series of Rux/NC catalysts using the thermolysis method for the oxidation of HMF to produce FDCA and found that Ru NPs and the NC easily support undergoing strong electronic interactions, forming electron-rich Ru0 NPs. These Ru0 NPs with a high electron density can promote the activation of O2 by strengthening the electron transfer from the 3D orbitals of Ru NPs to O2, generating superoxide radicals and other reactive oxygen species. This is conducive to the removal of accumulated electrons on the metal surface and improves the regeneration of Ru0 active centers, further enhancing the oxidation of HMF. For Pd based catalyst, Chen et al. [78] prepared a series of Pd catalysts supported on carbon materials (Pd/rGO, Pd/CNT, Pd/AC, and Pd/HPGs) with the same loading to compare their differences in the HMF oxidation reaction. Although Pd2+ is considered less stable than metallic Pd0, the Pd/HPGs catalyst, a highly porous nitrogen- and phosphorus-doped graphene-supported Pd catalyst, with the highest Pd2+, showed the best reaction activity and the lowest apparent activation energy (Ea) in the HMF oxidation reaction, as shown in Figure 5b. Subsequently, a linear correlation calculation was performed between the Ea values required for forming FDCA and the fraction of surface Pd2+. As shown in Figure 5c, the results indicated a negative correlation between the fraction of Pd2+ and Ea. Thus, HPGs promote the proportion of Pd2+ species in Pd/HPGs, thereby having the best HMF oxidation performance. In addition, in the Pd/HPGs catalyst, the transformation and balance of Pd2+ and Pd0 coordinate the catalytic cycle in the coexistence system of oxidation and reduction substrates, which is also conducive to the reaction.
In a word, the valence state of noble metal sites shows a significant impact on the catalytic oxidation of HMF to FDCA. Utilizing the coordinated or alloying effects of noble metal by introducing a second metal or additives for the efficient catalytic oxidation of HMF to produce FDCA has been focused. Zhang et al. [54] prepared PtxRu-MgAlO alloy catalysts with different metal ratios to investigate the impact of the alloy and metal active sites on the oxidation performance of HMF. Intense electronic transfer on the Pt-Ru surface generates many electron-rich Pt0 and electron-deficient Ru0 active sites, which are conducive to the aerobic oxidation of C=O and OH groups in HMF. Compared with other catalysts with different Pt/Ru ratios, the Pt2Ru-MgAlO catalyst exhibits the strongest redshift of the PtRu-(CO)m adsorption peak in FT-IR spectra of CO adsorption, as shown in Figure 5d. This suggests that the alloying between Pt and Ru can effectively adsorb and activate the C=O bond in HMF through the synergistic action at the Pt0-Ru0 sites. Furthermore, the Pt2Ru-MgAlO catalyst shows a faster increase of the FDCA conversion than the single Pt and Ru based catalysts, as shown in Figure 5e. When the Pt2Ru-MgAlO catalyst is used for HMF oxidation under conditions of 100 °C and 0.2 MPa air, both the conversion and selectivity of HMF to FDCA can reach up to 99%. Moreover, Zhang et al. [58] found by adjusting the ratio of Nb/Co on the Co@Nb-Pt catalyst surface, the content of Nb5+ species can be increased. On the catalyst surface, rich in Nb5+, sufficient Lewis acidic sites can be formed to promote the formation of stable electron-rich Pt0 active sites on the surface, as shown in Figure 5f. Calculations of the initial oxidation rate of HMF and intermediates indicate that the electron-rich Pt0 active sites can effectively adsorb and activate the C=O groups in HMF, DFF, and FFCA through strong interactions between Pt0 and the π*C-O bond with Pt, leading to efficient conversion of HMF to FDCA as shown in Figure 5g.
In summary, the valence state of noble metal sites mainly determines the activity of the oxidation of HMF to FDCA. Currently, it is possible to influence the formation and electronic state of metal sites by appropriately modifying the support, and to promote electron transfer through the interaction at the metal–support interface, thereby affecting the characteristics of the active sites. In addition, new supported catalysts can be designed and developed by controlling the electronic and geometric structures of active sites in the future.

3.2. Geometrical Effect of Metal Sites

In the oxidation reaction of HMF, the unique geometric effect of the catalyst can regulate the accessibility and activation between reactant molecules and active sites, which enabled the catalyst to exhibit excellent activity and specific selectivity. Moreover, metal particles of different sizes can regulate the distribution of products and the rate of HMF oxidation by affecting active sites, surface area, and the synergistic effects between components.
For the HMF oxidation reaction, noble metal particles with smaller particle diameters generally have more active sites and higher turnover frequencies (TOF), enhancing the interaction between metal and support. Lei et al. [79] prepared single-crystalline Pd (Pd-NOs and Pd-NCs) catalysts with the same crystal face but different particle sizes, as shown in Figure 6b,c). In reaction, Pd-NOs with a smaller particle size (6 nm) showed better HMF oxidation performance than Pd-NOs with a larger particle size (18 nm). Calculations revealed that the surface Pd atom percentage of the Pd-NOs (6 nm) catalyst is 23.87%, while that of Pd-Nos (18 nm) is only 8.68%. Therefore, the authors attributed the differences in particle size to the varying percentages of surface Pd atoms. Subsequently, after testing the Pd-NOs catalysts with different particle sizes under the same surface Pd atom percentage, it was found that both catalysts exhibited similar catalytic performance in the oxidation of HMF, confirming the aforementioned assumption. In addition, with similar particle size, Pd-NOs enclosed by {111} facets were more efficient than Pd-NCs enclosed by {100} facets for the aerobic oxidation of HMF, especially for the oxidation step from HMFCA to FFCA. For example, full HMF conversion and a 91.3% FDCA yield could be achieved over Pd-NOs (6 nm) within 4 h, while only a 33.1% FDCA yield and 98.3% HMF conversion could be obtained over Pd-NCs(7 nm) over a 12 h reaction. On the other hand, the interface formed between the support and the metal changes with the different exposed crystal faces of the support, and the morphology of different supports can also affect the catalytic activity by influencing the metal–support interface [80]. Li et al. [81,82] synthesized three different morphologies of catalysts, which are CeO2-rod, CeO2-cube, and CeO2-oct, through the hydrothermal method and used them to prepare different Au NPs. The Au NPs on CeO2-rod particle size is mainly around 2 nm, while those on CeO2-cube and CeO2-oct are mainly 2–4 nm and 3–5 nm, respectively, as illustrated in Figure 6d. The Au/CeO2-rod with the smallest particle size showed the highest activity in HMF oxidation reactions, with a TOF up to 6.3 (min−1). Neukum et al. [83] developed a bimetallic AgPd/CBA catalyst with different ratios and applied it to the oxidation of HMF. It was found that catalyst samples with different metal ratios had different average particle sizes, among which the catalyst Ag1Pd3/CBA with the smallest average particle size showed the best reaction performance among many catalysts. In addition, Ag has the ability to efficiently oxidize the C=O group in HMF, which is beneficial for the conversion of HMF to HMFCA. Compared with the monometallic Pd/CBA catalyst, the Ag1Pd3/CBA catalyst prepared by doping a small amount of Ag can significantly increase the yield of FDCA. This indicates that the presence of Ag can have a synergistic effect on Pd; Pd helps to activate O2 and generate active oxygen, and this activated oxygen can effectively remove H on the surface of Ag, thereby achieving the regeneration of Ag active sites and promoting the reaction. The Ag1Pd3/CBA catalyst with the best ratio was reacted under the conditions of 140 °C and 10 bar for 5 h, and the yield of FDCA can reach 63.9%. Rabee et al. [84] prepared supported catalysts with different morphologies, including monoclinic (m-), tetragonal (t-) ZrO2, and Mg-modified zirconia, for the catalytic oxidation of HMF to FDCA. Comparing the two unmodified samples, it was found that the gold particle size distribution on Au/t-ZrO2 was broader than that on Au/m-ZrO2. H2-TPR indicated that a single reduction peak appeared on the surface of t-ZrO2, while two reduction peaks were observed on the surfaces of m-ZrO2, Au/MZ-400, and Au/MZ-600, as shown in Figure 6e. In conjunction with other characterizations, it is realized that the main adsorption on the Au/t-ZrO2 support surface is [AuCl4]−, while the other three samples have both [AuCl4]− and [Au(OH)4]− adsorbed on their surfaces. Therefore, the authors concluded that the presence of [Au(OH)4]− is conducive to the formation of smaller gold NPs, while [AuCl4]− favors the formation of larger gold NPs. The difference in Au particle distribution is attributed to the different types of Au adsorbed on the support surfaces. The modified Au/MZ-400 and Au/MZ-600 exhibited a smaller particle size distribution, around 2 nm. In addition to the influence of the types of adsorbed Au, the additional magnesium also promoted better dispersion of Au particles. Compared to other samples, the Au/MZ-600 catalyst demonstrated a 93% yield of FDCA at 60 °C for a 4–5 h reaction, as shown in Figure 6f. Xia et al. [85] prepared a series of Pd-Au/HT bimetallic alloy catalysts. It was found that compared with the monometallic Au catalyst, the Pd-Au/HT catalyst showed a better reaction performance. The alloy formed between Pd and Au promoted the synergistic and electronic effects between Au and Pd metals, which is beneficial for improving the oxidation activity of HMF, thereby obtaining a higher FDCA yield. In addition, the addition of Pd can inhibit the growth of gold nanoparticles (NPs). With the addition of Pd, the particle size of Pd-Au/HT was significantly reduced from Au/HT (10.2 nm) to 3.4 nm, indicating that Pd can effectively promote the dispersion of Au, reduce its particle size, and improve its dispersibility, thereby increasing the active sites of the catalyst and improving the reaction efficiency.
Unlike the above-mentioned Pd and Au based catalysts, the enhancement in activity via reducing metal particle size is not observed on the Pt-based catalyst. Zhang et al. [86] found that the morphology of Pt could be controlled by altering the synthesis temperature. Under high-temperature conditions, the morphology of active Pt materials on microsphere carbon shells can transition from highly dispersed small NPs (less than 1 nm) to relatively larger porous Pt clusters (about 25 nm), forming a unique island-like structure, as shown in Figure 6g. This structure is beneficial for the enrichment of reactants and the formation of highly crystalline Pt, thereby enhancing the activity of the reaction. At 110 °C, the larger Pt clusters of the 110-Fe3O4@C@Pt catalyst can achieve 100% selectivity for FDCA within 4 h. In contrast, the FDCA yield of the 90-Fe3O4@C@Pt with small and ultra-dispersed Pt NPs is only 87.1%. Interestingly, Schade et al. [87] found that Au particles of different sizes have various effects on the oxidation of HMF. Small gold particles (2.1 nm) favor the oxidation of the C=O group in HMF but have weaker activity for the OH group oxidation; larger particles (2.9 nm) only favor the OH group oxidation. However, the catalyst with an average Au particle size of 2.7 nm (composed of a larger proportion of small particles mixed with larger particles) exhibits the highest activity in the HMF oxidation reaction. This may be the step effect on the surface of larger particles, which is conducive to eliminating β-H from reactants and intermediates, promoting the OH group oxidation. In contrast, hydrogen bonding on the surface of small particles hinders the oxidation process and is not conducive to the reaction proceeding.
Therefore, the size and structure associated with the exposed crystal faces of noble metal catalysts all impact the aerobic oxidation of HMF to FDCA. Currently, various supports with porous structures are widely used due to their unique surface properties and pore structures, which can efficiently disperse metal particles and exert a confining effect, thereby regulating the size of NPs. Moreover, utilizing the surface properties of the support, such as surface defects and functional groups, can regulate the distribution of active sites and form certain strong interactions between metal and supports, thereby promoting the progress of the reaction.

3.3. Metal–Support Interactions

The metal–support interaction is one of the most effective factors to enhance the activity and stability of metal catalysts in heterogeneous catalysis, which can regulate the electronic structure, active sites, and stability of the catalyst through the electronic interaction between the metal and the support [88,89,90]. By regulating the concentration and distribution of oxygen vacancies of supports, the performance of catalysts can be effectively improved, improving catalytic efficiency and selectivity. Liu et al. [46] successfully induced a strong metal–support interaction between Au-Pd NPs and TiO2 by introducing oxygen vacancies (Ov) through the treatment of the catalyst with citric acid. As Ov is the preferred nucleation site for AuPd NPs, it successfully anchors dispersed AuPd NPs on the TiOx support surface. Moreover, by adjusting the concentration of Ov, the size of the catalyst particles can be regulated; a higher concentration of Ov favors the formation of catalysts with smaller particle sizes, thereby exposing more active sites, which is beneficial for the oxidation of HMF. Concurrently, Ti3+ generated from the reduction in the support TiO2 can transfer electrons to the metallic AuPd NPs, promoting the formation of active sites at the AuPd-TiOx interface, thereby enhancing catalytic activity and selectivity. Under the optimal reaction conditions, the conversion of HMF reaches 100%, with a yield of FDCA at 98.4%, as shown in Figure 7a. Similarly, the oxides of rare earth metals with variable valence are used for doping noble metals and then modulating the electronic structure of active sites, locally activate oxygen vacancies and electrons, and promote the reaction. Yang et al. [91] found that in the three-dimensional ordered macroporous Pt/Ce1−xLaxO2−δ catalyst, the doping of La3+ led to lattice substitution in the support; the partial reduction in Ce4+ to Ce3+ enabled the spontaneous formation of stable Pt-O-Ce interfacial sites between Pt and Ce3+, facilitating electron transfer between Pt and the carrier CeO2. This generates a large number of Ptδ+ species, which promotes the adsorption and activation of O2, thereby enhancing the reaction activity. Additionally, due to varying amounts of La, the catalyst surface formed local environments with different Ov, as shown in Figure 7b. The La-□(-Ce)2 site exhibits a lower Ef (Fermi level, 0.75 eV) and appropriate Eads (O2− adsorption energy, −1.54 eV), indicating that these sites are reversible and thus considered to exhibit the best redox performance among different oxygen vacancies under various coordination environments. The DFT calculations (Figure 7c) show that compared with surface Pt NPs, the interface Pt/La-□(-Ce)2 exhibits a lower activation energy barrier (0.31 and 0.65 eV vs 0.41 and 0.91 eV) in the HMFCA→FFCA stage reaction. These results indicate that the strong metal–support interaction enhance the O2 adsorption, and then the oxidation activity, with a high TOF value of 5.78 min−1 at 90 °C.
In addition to the synergistic effects at the metal–support interface, the properties of the support, such as acidity and basicity, can also synchronize with metal sites to construct highly active sites for HMF oxidation or to enhance the reactivity. Zhu et al. [66] found that in the bifunctional Au/Mg-Beta catalyst, the basicity from the Mg-beta zeolite promoted the acceptance of electrons by Au NPs, thereby regulating the content of Auδ+ by modulating the electronic structure of Au, and improving the yield of FDCA. The content of Auδ+ shows a volcano relationship with the yield of FDCA; thus, under the optimal reaction conditions, the conversion of HMF and the yield of FDCA can reach up to 99.9%. Zhang et al. [92] found in the Ru/Cr-Fe-O catalyst that with the incorporation of Ru, the content of Fe2+ in the support significantly increased, promoting electron transfer and surface adsorption between Ru and the support, thereby generating a large number of Ru0 active sites to promote the activation of HMF. It is therefore believed that a strong metal–support interaction can modulate the electronic structure of Ru. In addition, adding Ru led to lattice defects in the Cr-Fe-O support and the formation of abundant weak acid sites on the surface of the support, which can improve HMF oxidation. Donoeva et al. [93] found that the basicity of the support greatly influences the oxidation activity of HMF and the selectivity of FDCA. Compared with acidic carbon materials, the Au/HSAG catalyst prepared on alkaline carbon materials shows high activity and selectivity for FDCA in the HMF reaction. The reasons for the aforementioned situation may be due to the fact that surface groups of the alkaline carbon support are positively charged, which is conducive to the adsorption of OH− cations on the surface of Au NPs and increases the local concentration, thereby enhancing the dehydrogenation rate, as illustrated in Figure 7d. Moreover, the size of Au particles supported on acidic carbon material HSAG-ox is larger than that of the original Au colloid particles, while for the HSAG-N with the basic carbon materials, the size and distribution of Au particles do not change, as shown in Figure 7e. These results indicate that basic carbon materials can better stabilize the size and distribution of Au NPs.
Chemistry 07 00017 g007
Figure 7. (a) Correlation analysis of Ov concentration and FDCA yield [46]. (b) DFT-calculated structure and the calculated values of Ef and O2− Eads on the sites of sites [91]. (c) Calculated energy profiles along with the optimized geometries of intermediates and transition states (TSs) for HMFCA oxidation toward FFCA on the interfacial Pt/La-□(-Ce)2 and Pt particles [91]. (d) Two possible scenarios of how basic or acidic surface groups on the carbon support can affect the adsorption of OH− [93]. (e) Representative TEM micrographs and corresponding particle size distribution histograms of different samples [93].
Figure 7. (a) Correlation analysis of Ov concentration and FDCA yield [46]. (b) DFT-calculated structure and the calculated values of Ef and O2− Eads on the sites of sites [91]. (c) Calculated energy profiles along with the optimized geometries of intermediates and transition states (TSs) for HMFCA oxidation toward FFCA on the interfacial Pt/La-□(-Ce)2 and Pt particles [91]. (d) Two possible scenarios of how basic or acidic surface groups on the carbon support can affect the adsorption of OH− [93]. (e) Representative TEM micrographs and corresponding particle size distribution histograms of different samples [93].
Chemistry 07 00017 g007
In summary, the rational utilization of the metal–support interaction is significant in constructing highly active catalysts. However, most HMF oxidation reactions are realized in a liquid-phase batch reactor under acidic or alkaline conditions, which poses great challenges to the loss and sintering of noble metal sites. Then, the metal–support interaction has been further developed to prepare encapsulated noble metal catalysts to improve the stability of catalysts, in light of the confinement effect.

3.4. Confinement Effect

Typically, zeolite materials have been developed to encapsulate noble metal NPs, with the hope of enhancing the interaction between the zeolite framework and the noble metal NPs within the confined space [94,95,96]. The unique pore structure of zeolites exerts a strong confinement effect on metal particles, effectively preventing noble metal particles from leaching and aggregating during the reaction process. Liu et al. [59] used Beta zeolite to encapsulate ultra-small Pt NPs within zeolite channels, relying on electrostatic interactions and the rigid shell of the zeolite framework to provide kinetic stability for Pt NPs, as shown in Figure 8a. The encapsulation regulates the accessibility of active sites within the zeolite micropores through adsorption and desorption, in which it shows a stronger adsorption capacity for HMFCA, FFCA, and FDCA, as shown in Figure 8b,c. Besides the zeolite materials, Lolli et al. [80] prepared an ordered mesoporous CeO2-encapsulated Au (Au/CeO2) catalyst using a stiff template method. Guan et al. [97] encapsulated Au-Pd alloy NPs within a structured carbon shell with a certain thickness, forming a unique shell structure that facilitated the entry of reactant molecules through the shell’s pores to enable contact with the active sites for oxidation. The confinement of bimetallic species together enhances the adsorption capacity of HMF and HMFCA, which promotes the adsorption and activation of molecular oxygen, generates more oxygen-active superoxide radicals, and enhances the catalytic activity of HMF, as shown in Figure 8d–g). The as-prepared Au2Pd1@C800 exhibits a high FDCA formation yield of 2003.6 mmol·g−1·h−1. Masoud et al. [98] found that in disordered porous silica support, the larger pores could not effectively promote the diffusion and limit the aggregation of Au NPs. These particles rapidly grow and form numerous aggregates within the pores, leading to a reduction in active surface area, which is unfavorable for the oxidation of HMF. When replacing mesoporous silica to ordered mesoporous cellular foam, the sintering and migration of Au NPs can be avoided. Liu et al. [99] used MgAl hydrotalcite (MgAl-HT) as a support to encapsulate Au-Ag bimetallic nanoclusters, in which the unique layer structure of the hydrotalcite can effectively disperse the Au-Ag nanoclusters, preventing metal aggregation and leaching. Zhong et al. [100] used amino-functionalized halloysite nanotubes (HNTs) via grafting of organic silanes on the HNTs’ surface. The electrostatic interaction on the surface uniformly anchored the PtCl62− and AuCl4− ionic groups and achieved a high dispersion of Pt-Au alloy NPs on the inner and outer surfaces of the nanotubes. In a word, an appropriate confinement effect can prevent the aggregation and sintering of noble metal sites during HMF oxidation, maintaining the original structure and activity of the catalyst.

4. Summary

Here, we provide a summary of the reaction mechanism for the catalytic oxidation of HMF to FDCA over noble metal catalysts. The oxidation of C=O and OH groups in HMF is a crucial step in the catalytic conversion of HMF, and the activity and selectivity of the reaction are sensitive to the geometric and electronic effect of noble metal sites. The rational design of functional sites of catalysts is beneficial for the tandem conversion of HMF to FDCA, in which the alloying and confinement effect are mainly focused. Currently, catalysts for the oxidation of HMF to FDCA have been extensively developed and applied, but there are still the following opportunities and challenges in future research and industrial applications:
(1)
For clarifying the role of the catalytic mechanism of bifunctional or multifunctional sites on the HMF oxidation reaction, controllable synthesis and distinguishing the active sites for the reaction is still challenging. Advanced in situ characterization technologies, together with DFT calculation, have been used to clarify the reaction pathways. However, the tandem conversion process is so complex that it is difficult to obtain accurate structural information by one means of characterization alone, and may not be realized by calculation. The chemical states and coordination environment of the metal species and oxygen species may change in the reaction process. In particular, in the frequently reported liquid-phase reaction systems, noble metal catalysts often suffer from metal leaching or poisoning deactivation. Thus, in future research, more effects should be devoted to the development of in situ or operando characterization techniques.
(2)
The selective oxidation of HMF over the noble metal-based catalyst has been frequently reported in the last few years. However, many challenges remain to be addressed. In fact, a reduction in noble metal loading is desired, as the noble metal loading reported for Pt-, Pd-, Ru-, and Au-based catalysts is generally high (>0.5 wt.%). Non-noble metals are more prone to low activity and selectivity under the as-reported reaction process. So far, non-noble metal catalysts, especially those with high activity and stability, are still rarely reported. Thus, the screening and design of ultra-small non-noble metal clusters or single non-noble metal atoms should be significant for developing efficient non-noble metal catalysts. In particular, single non-noble metal atom catalysts have been realized via selective oxidation. On the other hand, the alloying of a noble metal with a second metal is an effective strategy to reduce the amount of noble metal. Moreover, some intermetallic compounds (nitrides, carbides, and phosphides, etc.) as well as high-entropy alloys, which possess similar characters to noble metals, will be promising candidates.

Author Contributions

Methodology, writing—original draft preparation, Y.G.; writing—review and editing, Y.Z.; data curation, S.G. and B.L.; writing—review and editing, conceptualization, supervision, Z.W. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

No new data were created or analyzed in this study.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Jing, Y.; Guo, Y.; Xia, Q.; Liu, X.; Wang, Y. Catalytic Production of Value-Added Chemicals and Liquid Fuels from Lignocellulosic Biomass. Chem 2019, 5, 2520–2546. [Google Scholar] [CrossRef]
  2. Wu, X.; Zhai, Z.; Wu, J.; Tan, K.; Li, Z.; Yin, S. Modulation of hydroxymethyl/aldehyde groups activation on V2O3 decorated CuCo for 5-hydroxymethylfurfural electrooxidation. Chem. Eng. J. 2024, 485, 149774. [Google Scholar] [CrossRef]
  3. Cai, J.; Li, K.; Wu, S. Recent advances in catalytic conversion of biomass derived 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid. Biomass Bioenergy 2022, 158, 106358. [Google Scholar] [CrossRef]
  4. Li, J.; Zhao, R.; Xu, Y.; Wu, X.; Bean, S.R.; Wang, D. Fuel ethanol production from starchy grain and other crops: An overview on feedstocks, affecting factors, and technical advances. Renew. Energy 2022, 188, 223–239. [Google Scholar] [CrossRef]
  5. Manikandan, S.; Subbaiya, R.; Biruntha, M.; Krishnan, R.Y.; Muthusamy, G.; Karmegam, N. Recent development patterns, utilization and prospective of biofuel production: Emerging nanotechnological intervention for environmental sustainability – A review. Fuel 2022, 314, 122757. [Google Scholar] [CrossRef]
  6. Mathew, G.M.; Raina, D.; Narisetty, V.; Kumar, V.; Saran, S.; Pugazhendi, A.; Sindhu, R.; Pandey, A.; Binod, P. Recent advances in biodiesel production: Challenges and solutions. Sci. Total Environ. 2021, 794, 148751. [Google Scholar] [CrossRef]
  7. Masera, K.; Hossain, A.K. Advancement of biodiesel fuel quality and NOx emission control techniques. Renew. Sustain. Energy Rev. 2023, 178, 113235. [Google Scholar] [CrossRef]
  8. Cousin, E.; Namhaed, K.; Pérès, Y.; Cognet, P.; Delmas, M.; Hermansyah, H.; Gozan, M.; Alaba, P.A.; Aroua, M.K. Towards efficient and greener processes for furfural production from biomass: A review of the recent trends. Sci. Total Environ. 2022, 847, 157599. [Google Scholar] [CrossRef]
  9. Racha, A.; Samanta, C.; Sreekantan, S.; Marimuthu, B. Review on Catalytic Hydrogenation of Biomass-Derived Furfural to Furfuryl Alcohol: Recent Advances and Future Trends. Energy Fuels 2023, 37, 11475–11496. [Google Scholar] [CrossRef]
  10. Liu, H.; Tang, X.; Zeng, X.; Sun, Y.; Ke, X.; Li, T.; Zhang, J.; Lin, L. Catalyst design strategy toward the efficient heterogeneously-catalyzed selective oxidation of 5-hydroxymethylfurfural. Green Energy Environ. 2022, 7, 900–932. [Google Scholar] [CrossRef]
  11. Prajapati, A.; Govindarajan, N.; Sun, W.; Huang, J.; Bemana, H.; Feaster, J.T.; Akhade, S.A.; Kornienko, N.; Hahn, C. Mechanistic Insights into the Electrochemical Oxidation of 5-Hydroxymethylfurfural on a Thin-Film Ni Anode. ACS Catal. 2024, 14, 10122–10131. [Google Scholar] [CrossRef]
  12. Yang, L.; Liu, J.; Cheng, F.; Zhou, S.; Xu, Q.; Yin, D.; Liu, X. V-doped MoO3 nanorods for highly selective oxidation of 5-hydroxymethylfurfural to bio-monomer 2, 5-furandicarboxylic acid. Renew. Energy 2024, 226, 120409. [Google Scholar] [CrossRef]
  13. Wang, W.; Xu, H.; Sang, T.; Ji, D.; Hao, J.; Li, Z. CuO–Ni(OH)2 heterostructure nanosheets: A high-performance electrocatalyst for 5-hydroxymethylfurfural oxidation. Chem. Commun. 2024, 60, 4214–4217. [Google Scholar] [CrossRef] [PubMed]
  14. Chen, B.; Abe, Y.; Guo, H.; Lee Smith, R. Selective oxidation of 5-hydroxymethylfurfural over MnOx-CeO2 catalyst prepared with co-precipitation method. Fuel 2024, 376, 132745. [Google Scholar] [CrossRef]
  15. Wang, J.-G.; Liu, X.-Q.; Zhu, J. From Furan to High Quality Bio-based Poly(ethylene furandicarboxylate). Chin. J. Polym. Sci. 2018, 36, 720–727. [Google Scholar] [CrossRef]
  16. Bielski, R.; Grynkiewicz, G. Furan platform chemicals beyond fuels and plastics. Green Chem. 2021, 23, 7458–7487. [Google Scholar] [CrossRef]
  17. Lai, J.; Cheng, F.; Zhou, S.; Wen, S.; Guo, D.; Zhao, W.; Liu, X.; Yin, D. Base-free oxidation of 5-hydroxymethylfurfural to 2, 5-furan dicarboxylic acid over nitrogen-containing polymers supported Cu-doped MnO2 nanowires. Appl. Surf. Sci. 2021, 565, 150479. [Google Scholar] [CrossRef]
  18. Yue, X.; Queneau, Y. 5-Hydroxymethylfurfural and Furfural Chemistry Toward Biobased Surfactants. ChemSusChem 2022, 15, e202102660. [Google Scholar] [CrossRef]
  19. Anbu Anjugam Vandarkuzhali, S.; Karthikeyan, G.; Pachamuthu, M.P. Efficient oxidation of 5-Hydroxymethylfurfural to 2,5-furandicarboxylic acid over FeNPs@NH2-SBA-15 catalyst in water. Mol. Catal. 2021, 516, 111951. [Google Scholar] [CrossRef]
  20. Xia, H.; Xu, S.; Hu, H.; An, J.; Li, C. Efficient conversion of 5-hydroxymethylfurfural to high-value chemicals by chemo- and bio-catalysis. RSC Adv. 2018, 8, 30875–30886. [Google Scholar] [CrossRef]
  21. Hu, L.; Lin, L.; Wu, Z.; Zhou, S.; Liu, S. Recent advances in catalytic transformation of biomass-derived 5-hydroxymethylfurfural into the innovative fuels and chemicals. Renew. Sustain. Energy Rev. 2017, 74, 230–257. [Google Scholar] [CrossRef]
  22. Agarwal, B.; Kailasam, K.; Sangwan, R.S.; Elumalai, S. Traversing the history of solid catalysts for heterogeneous synthesis of 5-hydroxymethylfurfural from carbohydrate sugars: A review. Renew. Sustain. Energy Rev. 2018, 82, 2408–2425. [Google Scholar] [CrossRef]
  23. Pang, X.; Bai, H.; Zhao, H.; Fan, W.; Shi, W. Efficient Electrocatalytic Oxidation of 5-Hydroxymethylfurfural Coupled with 4-Nitrophenol Hydrogenation in a Water System. ACS Catal. 2022, 12, 1545–1557. [Google Scholar] [CrossRef]
  24. Sayed, M.; Pyo, S.-H.; Rehnberg, N.; Hatti-Kaul, R. Selective Oxidation of 5-Hydroxymethylfurfural to 5-Hydroxymethyl-2-furancarboxylic Acid Using Gluconobacter oxydans. ACS Sustain. Chem. Eng. 2019, 7, 4406–4413. [Google Scholar] [CrossRef]
  25. Zhou, P.; Pan, H.; Hai, G.; Liu, X.; Huang, X.; Wang, G. Expediting *OH accumulation kinetics on metal-organic frameworks-derived CoOOH with CeO2 “accelerator” for electrocatalytic 5-hydroxymethylfurfural oxidation valorization. J. Energy Chem. 2024, 98, 721–732. [Google Scholar] [CrossRef]
  26. Román-Leshkov, Y.; Chheda, J.N.; Dumesic, J.A. Phase Modifiers Promote Efficient Production of Hydroxymethylfurfural from Fructose. Science 2006, 312, 1933–1937. [Google Scholar] [CrossRef]
  27. Giannakoudakis, D.A.; Colmenares, J.C.; Tsiplakides, D.; Triantafyllidis, K.S. Nanoengineered Electrodes for Biomass-Derived 5-Hydroxymethylfurfural Electrocatalytic Oxidation to 2,5-Furandicarboxylic Acid. ACS Sustain. Chem. Eng. 2021, 9, 1970–1993. [Google Scholar] [CrossRef]
  28. Yang, M.; Yuan, Z.; Peng, R.; Wang, S.; Zou, Y. Recent Progress on Electrocatalytic Valorization of Biomass-Derived Organics. Energy Environ. Mater. 2022, 5, 1117–1138. [Google Scholar] [CrossRef]
  29. Cheng, S.; Zhong, H.; Jin, F. A mini review of electrocatalytic upgrading of carbohydrate biomass—System, path, and optimization. Energy Sci. Eng. 2023, 11, 2944–2965. [Google Scholar] [CrossRef]
  30. Upare, P.P.; Clarence, R.E.; Shin, H.; Park, B.G. An Overview on Production of Lignocellulose-Derived Platform Chemicals Such as 5-Hydroxymethyl Furfural, Furfural, Protocatechuic Acid. Processes 2023, 11, 2912. [Google Scholar] [CrossRef]
  31. Wang, Y.; Wang, H.; Kong, X.; Zhu, Y. Catalytic Conversion of 5-Hydroxymethylfurfural to High-Value Derivatives by Selective Activation of C−O, C=O, and C=C Bonds. ChemSusChem 2022, 15, e202200421. [Google Scholar] [CrossRef] [PubMed]
  32. Song, Z.; Liu, L.; Zhu, X.; Ren, Z.; Bai, J. Cobalt-based catalysts for catalytic oxidation of biomass-derived 5-Hydromethylfurfural to value-added chemicals. Renew. Sustain. Energy Rev. 2024, 189, 114003. [Google Scholar] [CrossRef]
  33. Deshan, A.D.K.; Atanda, L.; Moghaddam, L.; Rackemann, D.W.; Beltramini, J.; Doherty, W.O.S. Heterogeneous Catalytic Conversion of Sugars Into 2,5-Furandicarboxylic Acid. Front. Chem. 2020, 8. [Google Scholar] [CrossRef]
  34. Lin, Z.; Chen, X.; Lu, L.; Yao, X.; Zhai, C.; Tao, H. Recent advances in electrocatalytic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid: Mechanism, catalyst, coupling system. Nanotechnol. Rev. 2023, 12. [Google Scholar] [CrossRef]
  35. Gawade, A.B.; Nakhate, A.V.; Yadav, G.D. Selective synthesis of 2, 5-furandicarboxylic acid by oxidation of 5-hydroxymethylfurfural over MnFe2O4 catalyst. Catal. Today 2018, 309, 119–125. [Google Scholar] [CrossRef]
  36. Verma, S.; Nadagouda, M.N.; Varma, R.S. Porous nitrogen-enriched carbonaceous material from marine waste: Chitosan-derived carbon nitride catalyst for aerial oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid. Sci. Rep. 2017, 7, 13596. [Google Scholar] [CrossRef]
  37. Li, X.; Zhu, R. Solvent-promoted and acid- controlled selectivity oxidation of 5-hydroxymethylfurfural over metal-free TEMPO catalyst. Appl. Catal. A Gen. 2022, 636, 118600. [Google Scholar] [CrossRef]
  38. Wu, J.; Xie, W.; Zhang, Y.; Ke, X.; Li, T.; Fang, H.; Sun, Y.; Zeng, X.; Lin, L.; Tang, X. Oxygen-vacancy-rich MnOx supported RuOx for efficient base-free oxidation of 5-hydroxymethylfurfural and 5-methoxymethylfurfural to 2,5-furandicarboxylic acid. J. Energy Chem. 2024, 95, 670–683. [Google Scholar] [CrossRef]
  39. Zhao, S.; Wang, K.; Mao, S.; Yang, B.; Zhao, Y. Toward Maximizing the Ag–CeO2 Interface and Rich Oxygen Vacancies for Efficient Photocatalytic Oxidation of 5-Hydroxymethylfurfural. ACS Sustain. Chem. Eng. 2025. [Google Scholar] [CrossRef]
  40. Cavallo, M.; Ramadhan, Z.R.; Somerville, S.V.; Han, E.; Webster, R.F.; Cheong, S.; Baldino, S.; Lessio, M.; Gooding, J.J.; Tilley, R.D. Enhancing the Electrocatalytic Oxidation of 5-Hydroxymethylfurfural (HMF) via Metallic Cobalt in Au–Co Nanoparticles. J. Phys. Chem. C 2025. [Google Scholar] [CrossRef]
  41. Chen, S.; Guo, X.; Ban, H.; Pan, T.; Zheng, L.; Cheng, Y.; Wang, L.; Li, X. Reaction Mechanism and Kinetics of the Liquid-Phase Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid. Ind. Eng. Chem. Res. 2021, 60, 16887–16898. [Google Scholar] [CrossRef]
  42. Chen, C.; Lv, M.; Hu, H.; Huai, L.; Zhu, B.; Fan, S.; Wang, Q.; Zhang, J. 5-Hydroxymethylfurfural and its Downstream Chemicals: A Review of Catalytic Routes. Adv. Mater. 2024, 36, 2311464. [Google Scholar] [CrossRef] [PubMed]
  43. Yang, X.; Zhang, Y.; Sun, P.; Peng, C. A review on renewable energy: Conversion and utilization of biomass. Smart Mol. 2024, 2, e20240019. [Google Scholar] [CrossRef]
  44. Kay Lup, A.N.; Abnisa, F.; Daud, W.M.A.W.; Aroua, M.K. A review on reaction mechanisms of metal-catalyzed deoxygenation process in bio-oil model compounds. Appl. Catal. A Gen. 2017, 541, 87–106. [Google Scholar] [CrossRef]
  45. Zhang, D.; Dumont, M.-J. Advances in polymer precursors and bio-based polymers synthesized from 5-hydroxymethylfurfural. J. Polym. Sci. Part A Polym. Chem. 2017, 55, 1478–1492. [Google Scholar] [CrossRef]
  46. Liu, Y.; Chen, Y.; Li, Y.; Guan, W.; Xia, Q.; Cao, M.; Huo, P.; Zhang, Y. Oxygen vacancy-driven strong metal-support interactions on AuPd/TiO2 catalysts for high-efficient air-oxidation of 5-hydroxymethylfurfural. Chem. Eng. J. 2023, 476, 146874. [Google Scholar] [CrossRef]
  47. Lu, X.; Wu, K.-H.; Zhang, B.; Chen, J.; Li, F.; Su, B.-J.; Yan, P.; Chen, J.-M.; Qi, W. Highly Efficient Electro-reforming of 5-Hydroxymethylfurfural on Vertically Oriented Nickel Nanosheet/Carbon Hybrid Catalysts: Structure–Function Relationships. Angew. Chem. Int. Ed. 2021, 60, 14528–14535. [Google Scholar] [CrossRef]
  48. Zhang, Y.; Liu, Y.; Guan, W.; Cao, M.; Chen, Y.; Huo, P. Strong metal-support interaction between AuPd nanoparticles and oxygen-rich defect ZrO2 for enhanced catalytic 5-hydroxymethylfurfural oxidation. Chin. Chem. Lett. 2024, 35, 108932. [Google Scholar] [CrossRef]
  49. Liao, W.; Lin, H.; Zhang, J.; Wang, J.; Yang, K.; Su, T.; Lü, H.; Zhu, Z. Au/Sn-Beta catalyst with metal-Lewis acid cooperative sites steers aerobic oxidation of 5-hydroxymethylfurfural. Appl. Surf. Sci. 2023, 608, 155154. [Google Scholar] [CrossRef]
  50. Wang, Y.; Yu, K.; Lei, D.; Si, W.; Feng, Y.; Lou, L.-L.; Liu, S. Basicity-Tuned Hydrotalcite-Supported Pd Catalysts for Aerobic Oxidation of 5-Hydroxymethyl-2-furfural under Mild Conditions. ACS Sustain. Chem. Eng. 2016, 4, 4752–4761. [Google Scholar] [CrossRef]
  51. Zhao, D.; Su, T.; Len, C.; Luque, R.; Yang, Z. Recent advances in the oxidative esterification of 5-hydroxymethylfurfural to furan-2,5-dimethylcarboxylate. Green Chem. 2022, 24, 6782–6789. [Google Scholar] [CrossRef]
  52. Rao, B.S.; Hidajat, M.J.; Yun, G.-N.; Hwang, D.W. Highly active and stable Ru–(OH)-based catalysts supported on Ni–manganite for the base-free aerobic oxidation of 5-hydroxymethyl furfural to 2,5-furan dicarboxylic acid in a noble water–organic solvent system. Catal. Sci. Technol. 2023, 13, 6921–6936. [Google Scholar] [CrossRef]
  53. Cui, X.; Zheng, L.; Li, Q.; Guo, Y. Nitrogen-Doped and Pt–Pd-Decorated Porous Carbon Catalyst Derived from Biotar for 2,5-Furandicarboxylic Acid Production from Selective Oxidation of 5-Hydroxymethylfurfural in an Alkali-Free Environment. Ind. Eng. Chem. Res. 2023, 62, 14973–14985. [Google Scholar] [CrossRef]
  54. Zhang, H.; Gao, T.; Zhang, Q.; Gu, B.; Tang, Q.; Cao, Q.; Fang, W. Synergistic catalysis in loaded PtRu alloy nanoparticles to boost base-free aerobic oxidation of 5-hydroxymethylfurfural. Mater. Today Catal. 2023, 3, 100013. [Google Scholar] [CrossRef]
  55. Tharat, B.; Ngamwongwan, L.; Seehamongkol, T.; Rungtaweevoranit, B.; Nonkumwong, J.; Suthirakun, S.; Faungnawakij, K.; Chanlek, N.; Plucksacholatarn, A.; Nimsaila, W.; et al. Hydroxy and surface oxygen effects on 5-hydroxymethylfurfural oxidation to 2,5-furandicarboxylic acid on β-MnO2: DFT, microkinetic and experiment studies. Nanoscale 2024, 16, 678–690. [Google Scholar] [CrossRef]
  56. Zhu, W.; Meng, Y.; Yang, C.; Zhao, J.; Wang, H.; Hu, W.; Lv, G.; Wang, Y.; Deng, T.; Hou, X. Effect of Coordination Environment Surrounding a Single Pt Site on the Liquid-Phase Aerobic Oxidation of 5-Hydroxymethylfurfural. ACS Appl. Mater. Interfaces 2021, 13, 48582–48594. [Google Scholar] [CrossRef]
  57. Cheng, X.; Li, S.; Liu, S.; Xin, Y.; Yang, J.; Chen, B.; Liu, H. Highly efficient catalytic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid using bimetallic Pt–Cu alloy nanoparticles as catalysts. Chem. Commun. 2022, 58, 1183–1186. [Google Scholar] [CrossRef]
  58. Zhang, H.; Zhang, R.; Zhang, W.; Gu, B.; Tang, Q.; Cao, Q.; Fang, W. Base-free selective oxidation of 5-hydroxymethylfurfural over Pt nanoparticles on surface Nb-enriched Co-Nb oxide. Appl. Catal. B Environ. 2023, 330, 122670. [Google Scholar] [CrossRef]
  59. Liu, X.; Chen, L.; Xu, H.; Jiang, S.; Zhou, Y.; Wang, J. Straightforward synthesis of beta zeolite encapsulated Pt nanoparticles for the transformation of 5-hydroxymethyl furfural into 2,5-furandicarboxylic acid. Chin. J. Catal. 2021, 42, 994–1003. [Google Scholar] [CrossRef]
  60. Zhang, H.; Fan, B.; Bian, L.; Tang, Q.; Cao, Q.; Fang, W. Influence of NiO-calcination on Pt-supported catalyst for selective oxidation of 5-hydroxymethylfurfural. Catal. Commun. 2023, 184, 106791. [Google Scholar] [CrossRef]
  61. Salakhum, S.; Prasertsab, A.; Pornsetmetakul, P.; Saenluang, K.; Iadrat, P.; Chareonpanich, M.; Wattanakit, C. Pt Nanoparticles on ZSM-5 Nanoparticles for Base-Free Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid. ACS Appl. Nano Mater. 2021, 4, 14047–14059. [Google Scholar] [CrossRef]
  62. Zhou, C.; Shi, W.; Wan, X.; Meng, Y.; Yao, Y.; Guo, Z.; Dai, Y.; Wang, C.; Yang, Y. Oxidation of 5-hydroxymethylfurfural over a magnetic iron oxide decorated rGO supporting Pt nanocatalyst. Catal. Today 2019, 330, 92–100. [Google Scholar] [CrossRef]
  63. Antonyraj, C.A.; Huynh, N.T.T.; Lee, K.W.; Kim, Y.J.; Shin, S.; Shin, J.S.; Cho, J.K. Base-free oxidation of 5-hydroxymethyl-2-furfural to 2,5-furan dicarboxylic acid over basic metal oxide-supported ruthenium catalysts under aqueous conditions. J. Chem. Sci. 2018, 130, 156. [Google Scholar] [CrossRef]
  64. Mishra, D.K.; Lee, H.J.; Kim, J.; Lee, H.-S.; Cho, J.K.; Suh, Y.-W.; Yi, Y.; Kim, Y.J. MnCo2O4 spinel supported ruthenium catalyst for air-oxidation of HMF to FDCA under aqueous phase and base-free conditions. Green Chem. 2017, 19, 1619–1623. [Google Scholar] [CrossRef]
  65. Gao, T.; Chen, J.; Fang, W.; Cao, Q.; Su, W.; Dumeignil, F. Ru/MnXCe1OY catalysts with enhanced oxygen mobility and strong metal-support interaction: Exceptional performances in 5-hydroxymethylfurfural base-free aerobic oxidation. J. Catal. 2018, 368, 53–68. [Google Scholar] [CrossRef]
  66. Zhu, Z.; Gao, X.; Wang, X.; Yin, M.; Wang, Q.; Ren, W.; Wang, B.; Lü, H.; Liao, W. Rational construction of metal–base synergetic sites on Au/Mg-beta catalyst for selective aerobic oxidation of 5-hydroxymethylfurfural. J. Energy Chem. 2021, 62, 599–609. [Google Scholar] [CrossRef]
  67. Megías-Sayago, C.; Lolli, A.; Ivanova, S.; Albonetti, S.; Cavani, F.; Odriozola, J.A. Au/Al2O3 – Efficient catalyst for 5-hydroxymethylfurfural oxidation to 2,5-furandicarboxylic acid. Catal. Today 2019, 333, 169–175. [Google Scholar] [CrossRef]
  68. Ferraz, C.P.; Costa, N.J.S.; Teixeira-Neto, E.; Teixeira-Neto, Â.A.; Liria, C.W.; Thuriot-Roukos, J.; Machini, M.T.; Froidevaux, R.; Dumeignil, F.; Rossi, L.M.; et al. 5-Hydroxymethylfurfural and Furfural Base-Free Oxidation over AuPd Embedded Bimetallic Nanoparticles. Catalysts 2020, 10, 75. [Google Scholar] [CrossRef]
  69. Lv, G.; Zhang, Z.; Liu, S.; Tao, F.; Wang, J.; Meng, Y.; Yang, Y. Atom level revelation of the synergistic effect between Pd and Au atoms in PdAu nanoalloy catalyst for aerobic oxidation of 5-hydroxymethylfurfural. Chem. Eng. J. 2023, 453, 139816. [Google Scholar] [CrossRef]
  70. Guan, W.; Zhang, Y.; Wei, Y.; Li, B.; Feng, Y.; Yan, C.; Huo, P.; Yan, Y. Pickering HIPEs derived hierarchical porous nitrogen-doped carbon supported bimetallic AuPd catalyst for base-free aerobic oxidation of HMF to FDCA in water. Fuel 2020, 278, 118362. [Google Scholar] [CrossRef]
  71. He, M.; Cao, Y.; Ji, J.; Li, K.; Huang, H. Superior catalytic performance of Pd-loaded oxygen-vacancy-rich TiO2 for formaldehyde oxidation at room temperature. J. Catal. 2021, 396, 122–135. [Google Scholar] [CrossRef]
  72. Dong, J.; Li, D.; Zhang, Y.; Chang, P.; Jin, Q. Insights into the CeO2 facet-depended performance of propane oxidation over Pt-CeO2 catalysts. J. Catal. 2022, 407, 174–185. [Google Scholar] [CrossRef]
  73. Rui, T.; Lu, G.-P.; Zhao, X.; Cao, X.; Chen, Z. The synergistic catalysis on Co nanoparticles and CoNx sites of aniline-modified ZIF derived Co@NCs for oxidative esterification of HMF. Chin. Chem. Lett. 2021, 32, 685–690. [Google Scholar] [CrossRef]
  74. Ma, J.; Wang, J.; Liu, J.; Li, X.; Sun, Y.; Li, R. Electron-rich ruthenium encapsulated in nitrogen-doped carbon for efficient hydrogen evolution reaction over the whole pH. J. Colloid Interface Sci. 2022, 620, 242–252. [Google Scholar] [CrossRef]
  75. Zhang, H.; Gao, T.; Cao, Q.; Fang, W. Tailoring the Reactive Oxygen Species in Mesoporous NiO for Selectivity-Controlled Aerobic Oxidation of 5-Hydroxymethylfurfural on a Loaded Pt Catalyst. ACS Sustain. Chem. Eng. 2021, 9, 6056–6067. [Google Scholar] [CrossRef]
  76. Fu, M.; Yang, W.; Yang, C.; Zhang, Y.; Shen, C. Mechanistic insights into CoOx–Ag/CeO2 catalysts for the aerobic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid. Catal. Sci. Technol. 2022, 12, 116–123. [Google Scholar] [CrossRef]
  77. Zhang, J.; Chen, P.; Liu, H.; Zhang, R.; Jia, W.; Zhang, J.; Peng, L. Electron-rich ruthenium nanoparticles on nitrogen-doped carbon for the efficient catalytic oxidation of 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid. Appl. Catal. A Gen. 2024, 676, 119663. [Google Scholar] [CrossRef]
  78. Chen, C.; Li, X.; Wang, L.; Liang, T.; Wang, L.; Zhang, Y.; Zhang, J. Highly Porous Nitrogen- and Phosphorus-Codoped Graphene: An Outstanding Support for Pd Catalysts to Oxidize 5-Hydroxymethylfurfural into 2,5-Furandicarboxylic Acid. ACS Sustain. Chem. Eng. 2017, 5, 11300–11306. [Google Scholar] [CrossRef]
  79. Lei, D.; Yu, K.; Li, M.-R.; Wang, Y.; Wang, Q.; Liu, T.; Liu, P.; Lou, L.-L.; Wang, G.; Liu, S. Facet Effect of Single-Crystalline Pd Nanocrystals for Aerobic Oxidation of 5-Hydroxymethyl-2-furfural. ACS Catal. 2017, 7, 421–432. [Google Scholar] [CrossRef]
  80. Lolli, A.; Amadori, R.; Lucarelli, C.; Cutrufello, M.G.; Rombi, E.; Cavani, F.; Albonetti, S. Hard-template preparation of Au/CeO2 mesostructured catalysts and their activity for the selective oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid. Microporous Mesoporous Mater. 2016, 226, 466–475. [Google Scholar] [CrossRef]
  81. Li, Q.; Wang, H.; Tian, Z.; Weng, Y.; Wang, C.; Ma, J.; Zhu, C.; Li, W.; Liu, Q.; Ma, L. Selective oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid over Au/CeO2 catalysts: The morphology effect of CeO2. Catal. Sci. Technol. 2019, 9, 1570–1580. [Google Scholar] [CrossRef]
  82. Si, R.; Flytzani-Stephanopoulos, M. Shape and Crystal-Plane Effects of Nanoscale Ceria on the Activity of Au-CeO2 Catalysts for the Water–Gas Shift Reaction. Angew. Chem. Int. Ed. 2008, 47, 2884–2887. [Google Scholar] [CrossRef] [PubMed]
  83. Neukum, D.; Ludwig, M.E.; Uzunidis, G.; Lakshmi Nilayam, A.R.; Krause, B.; Behrens, S.; Grunwaldt, J.-D.; Saraçi, E. Synergy of Ag and Pd in bimetallic catalysts for the selective oxidation of 5-(hydroxymethyl)furfural. Catal. Sci. Technol. 2024, 14, 7163–7171. [Google Scholar] [CrossRef]
  84. Rabee, A.I.M.; Le, S.D.; Higashimine, K.; Nishimura, S. Aerobic Oxidation of 5-Hydroxymethylfurfural into 2,5-Furandicarboxylic Acid over Gold Stabilized on Zirconia-Based Supports. ACS Sustain. Chem. Eng. 2020, 8, 7150–7161. [Google Scholar] [CrossRef]
  85. Xia, H.; An, J.; Hong, M.; Xu, S.; Zhang, L.; Zuo, S. Aerobic oxidation of 5-hydroxymethylfurfural to 2,5-difurancarboxylic acid over Pd-Au nanoparticles supported on Mg-Al hydrotalcite. Catal. Today 2019, 319, 113–120. [Google Scholar] [CrossRef]
  86. Zhang, Y.; Xue, Z.; Wang, J.; Zhao, X.; Deng, Y.; Zhao, W.; Mu, T. Controlled deposition of Pt nanoparticles on Fe3O4@carbon microspheres for efficient oxidation of 5-hydroxymethylfurfural. RSC Adv. 2016, 6, 51229–51237. [Google Scholar] [CrossRef]
  87. Schade, O.; Dolcet, P.; Nefedov, A.; Huang, X.; Saraçi, E.; Wöll, C.; Grunwaldt, J.-D. The Influence of the Gold Particle Size on the Catalytic Oxidation of 5-(Hydroxymethyl)furfural. Catalysts 2020, 10, 342. [Google Scholar] [CrossRef]
  88. Sang, K.; Zuo, J.; Zhang, X.; Wang, Q.; Chen, W.; Qian, G.; Duan, X. Towards a molecular understanding of the electronic metal-support interaction (EMSI) in heterogeneous catalysis. Green Energy Environ. 2023, 8, 619–625. [Google Scholar] [CrossRef]
  89. Yang, J.; Li, W.; Wang, D.; Li, Y. Electronic Metal–Support Interaction of Single-Atom Catalysts and Applications in Electrocatalysis. Adv. Mater. 2020, 32, 2003300. [Google Scholar] [CrossRef]
  90. Fu, J.; Zhang, X.; Li, H.; Chen, B.; Ye, S.; Zhang, N.; Yu, Z.; Zheng, J.; Chen, B. Enhancing electronic metal support interaction (EMSI) over Pt/TiO2 for efficient catalytic wet air oxidation of phenol in wastewater. J. Hazard. Mater. 2022, 426, 128088. [Google Scholar] [CrossRef]
  91. Yang, W.; Yu, H.; Wang, B.; Wang, X.; Zhang, H.; Lei, D.; Lou, L.-L.; Yu, K.; Liu, S. Leveraging Pt/Ce1–xLaxO2−δ To Elucidate Interfacial Oxygen Vacancy Active Sites for Aerobic Oxidation of 5-Hydroxymethylfurfural. ACS Appl. Mater. Interfaces 2022, 14, 37667–37680. [Google Scholar] [CrossRef] [PubMed]
  92. Zhang, S.; Yang, Y.; Chu, G.; Wang, S.; Wang, C.; Zhang, Y.; Zhang, L.; Mei, J. Surface chemistry regulation on particle-support interaction of ruthenium and Cr-Fe oxides for selective oxidation of 5-hydroxymethylfurfural. Chem. Eng. J. 2023, 474, 145670. [Google Scholar] [CrossRef]
  93. Donoeva, B.; Masoud, N.; de Jongh, P.E. Carbon Support Surface Effects in the Gold-Catalyzed Oxidation of 5-Hydroxymethylfurfural. ACS Catal. 2017, 7, 4581–4591. [Google Scholar] [CrossRef] [PubMed]
  94. Goel, S.; Zones, S.I.; Iglesia, E. Encapsulation of Metal Clusters within MFI via Interzeolite Transformations and Direct Hydrothermal Syntheses and Catalytic Consequences of Their Confinement. J. Am. Chem. Soc. 2014, 136, 15280–15290. [Google Scholar] [CrossRef]
  95. Iida, T.; Zanchet, D.; Ohara, K.; Wakihara, T.; Román-Leshkov, Y. Concerted Bimetallic Nanocluster Synthesis and Encapsulation via Induced Zeolite Framework Demetallation for Shape and Substrate Selective Heterogeneous Catalysis. Angew. Chem. Int. Ed. 2018, 57, 6454–6458. [Google Scholar] [CrossRef]
  96. Otto, T.; Zones, S.I.; Iglesia, E. Challenges and strategies in the encapsulation and stabilization of monodisperse Au clusters within zeolites. J. Catal. 2016, 339, 195–208. [Google Scholar] [CrossRef]
  97. Guan, W.; Chen, Y.; Li, Y.; Wang, F.; Cao, M.; Liu, Y.; Pan, J.; Zhang, Y. Carbon-shell-encapsulated gold–palladium nanoreactors for highly efficient 5-hydroxymethylfurfural oxidation: Confinement and alloy effects study. Chem. Eng. Sci. 2024, 286, 119666. [Google Scholar] [CrossRef]
  98. Masoud, N.; Donoeva, B.; de Jongh, P.E. Stability of gold nanocatalysts supported on mesoporous silica for the oxidation of 5-hydroxymethyl furfural to furan-2,5-dicarboxylic acid. Appl. Catal. A Gen. 2018, 561, 150–157. [Google Scholar] [CrossRef]
  99. Liu, Z.; Tan, Y.; Li, J.; Li, X.; Xiao, Y.; Su, J.; Chen, X.; Qiao, B.; Ding, Y. Ag substituted Au clusters supported on Mg-Al-hydrotalcite for highly efficient base-free aerobic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid. Green Chem. 2022, 24, 8840–8852. [Google Scholar] [CrossRef]
  100. Zhong, X.; Yuan, P.; Wei, Y.; Liu, D.; Losic, D.; Li, M. Coupling Natural Halloysite Nanotubes and Bimetallic Pt–Au Alloy Nanoparticles for Highly Efficient and Selective Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid. ACS Appl. Mater. Interfaces 2022, 14, 3949–3960. [Google Scholar] [CrossRef]
Chemistry 07 00017 g002
Figure 2. Routes for the synthesis of FDCA [45].
Figure 2. Routes for the synthesis of FDCA [45].
Chemistry 07 00017 g002
Chemistry 07 00017 g003
Figure 3. (a) Possible mechanism of HMF oxidation to FDCA over Au2Pd1/TiO2-−0.4CA@HNTs catalyst [46]. (b) DFT calculations of HMF adsorption on Ni and NiOOH, (*: represents the transition state form of reactants or products) [47].
Figure 3. (a) Possible mechanism of HMF oxidation to FDCA over Au2Pd1/TiO2-−0.4CA@HNTs catalyst [46]. (b) DFT calculations of HMF adsorption on Ni and NiOOH, (*: represents the transition state form of reactants or products) [47].
Chemistry 07 00017 g003
Chemistry 07 00017 g004
Figure 4. (a) Plausible reaction mechanism of HMF oxidation over Ru-(OH) supported on the Ni1Mn6 catalyst [52]. (b) DFT calculations of Gibbs free energy profile of HMF oxidation on the bare β-MnO2(110) surface [55].
Figure 4. (a) Plausible reaction mechanism of HMF oxidation over Ru-(OH) supported on the Ni1Mn6 catalyst [52]. (b) DFT calculations of Gibbs free energy profile of HMF oxidation on the bare β-MnO2(110) surface [55].
Chemistry 07 00017 g004
Chemistry 07 00017 g005
Figure 5. (a) Relationship between the initial base-free aerobic oxidation of HMF and intermediates and the fraction of Pt0 and Olatt in the Pt/Nix catalysts [75]. (b) Kinetic measurements and analysis Ea (kJ mol–1) obtained within 1 h reaction time [78]. (c) Correlation between activation energies and surface Pd2+ fractions over the four catalysts [78]. (d) In situ DRIFT-IR spectra of CO adsorption after a purge of 5 min with He for a. Pt-MgAlO, b. Pt3Ru-MgAlO, c. Pt2Ru-MgAlO, d. Pt1Ru-MgAlO, e. Pt0.5Ru-MgAlO, f. Ru-MgAlO catalysts [54]. (e) Relationship between the normalized proportion of peak (1028 cm−1) within the 1000–1070 cm−1 band and the purging time [54]. (f) Relationship between the initials for the base-free aerobic oxidation of HMF, DFF, and FFCA and the surface Nb/Co ratio fraction, Lewis acidity, and Pt0 in the series supported Pt catalysts [58]. (g) Mechanistic illustration for the aqueous-phase aerobic oxidation of C=O bond in HMF and its oxidizing intermediates over the Co@Nb-Pt catalyst [58].
Figure 5. (a) Relationship between the initial base-free aerobic oxidation of HMF and intermediates and the fraction of Pt0 and Olatt in the Pt/Nix catalysts [75]. (b) Kinetic measurements and analysis Ea (kJ mol–1) obtained within 1 h reaction time [78]. (c) Correlation between activation energies and surface Pd2+ fractions over the four catalysts [78]. (d) In situ DRIFT-IR spectra of CO adsorption after a purge of 5 min with He for a. Pt-MgAlO, b. Pt3Ru-MgAlO, c. Pt2Ru-MgAlO, d. Pt1Ru-MgAlO, e. Pt0.5Ru-MgAlO, f. Ru-MgAlO catalysts [54]. (e) Relationship between the normalized proportion of peak (1028 cm−1) within the 1000–1070 cm−1 band and the purging time [54]. (f) Relationship between the initials for the base-free aerobic oxidation of HMF, DFF, and FFCA and the surface Nb/Co ratio fraction, Lewis acidity, and Pt0 in the series supported Pt catalysts [58]. (g) Mechanistic illustration for the aqueous-phase aerobic oxidation of C=O bond in HMF and its oxidizing intermediates over the Co@Nb-Pt catalyst [58].
Chemistry 07 00017 g005
Chemistry 07 00017 g006
Figure 6. (a) HRTEM images with the particle size distribution of (A,B) Pd-Nos (6 nm) and (C,D) Pd-Nos (18 nm) [79]. (b) Reaction profiles for HMF oxidation over Pd-NOs catalysts at ambient pressure. Reaction conditions: ntotal Pd/nHMF (mol/mol) = 4%, nNaHCO3/nHMF (mol/mol) = 4, 90 °C, O2 bubbling (25 mL/min) [79]. (c) Reaction profiles for HMF oxidation over Pd-NOs catalysts at ambient pressure. Reaction conditions: nsurface Pd/nHMF (mol/mol) = 0.6%, nNaHCO3/nHMF (mol/mol) = 4, 90 °C, O2 bubbling (25 mL/min) [79]. (d) Electron microscopy images: CeO2-rod (A,B); Au/CeO2-rod (C); CeO2-cube (D,E); Au/CeO2-cube (F); and CeO2-oct (G,H); Au/CeO2-oct (I) [81]. (e) H2-TPR profiles of un-calcined gold species (Au3+) supported on the different studied supports [84]. (f) Time-based reaction progress for the yield of FDCA via the anaerobic oxidation of HMF. Reaction conditions: 60 °C, 0.5 mmol HMF, NaOH (6 mL, NaOH/HMF molar ratio = 4), 100 mg catalyst, 50 mL min−1 O2 [84]. (g) Schematic illustration of the synthesis of superparamagnetic core/shell X-Fe3O4@C@Pt microspheres, where X indicates the refluxing temperature [86].
Figure 6. (a) HRTEM images with the particle size distribution of (A,B) Pd-Nos (6 nm) and (C,D) Pd-Nos (18 nm) [79]. (b) Reaction profiles for HMF oxidation over Pd-NOs catalysts at ambient pressure. Reaction conditions: ntotal Pd/nHMF (mol/mol) = 4%, nNaHCO3/nHMF (mol/mol) = 4, 90 °C, O2 bubbling (25 mL/min) [79]. (c) Reaction profiles for HMF oxidation over Pd-NOs catalysts at ambient pressure. Reaction conditions: nsurface Pd/nHMF (mol/mol) = 0.6%, nNaHCO3/nHMF (mol/mol) = 4, 90 °C, O2 bubbling (25 mL/min) [79]. (d) Electron microscopy images: CeO2-rod (A,B); Au/CeO2-rod (C); CeO2-cube (D,E); Au/CeO2-cube (F); and CeO2-oct (G,H); Au/CeO2-oct (I) [81]. (e) H2-TPR profiles of un-calcined gold species (Au3+) supported on the different studied supports [84]. (f) Time-based reaction progress for the yield of FDCA via the anaerobic oxidation of HMF. Reaction conditions: 60 °C, 0.5 mmol HMF, NaOH (6 mL, NaOH/HMF molar ratio = 4), 100 mg catalyst, 50 mL min−1 O2 [84]. (g) Schematic illustration of the synthesis of superparamagnetic core/shell X-Fe3O4@C@Pt microspheres, where X indicates the refluxing temperature [86].
Chemistry 07 00017 g006
Chemistry 07 00017 g008
Figure 8. (a) Schematic diagram for the preparation of Pt@Beta [59]. (b) Adsorption amount of HMF, HMFCA, FFCA, and FDCA on 0.2% Pt@Beta [59]. (c) Adsorption amount of HMF, HMFCA, FFCA, and FDCA on 0.2% Pt/Beta [59]. (d) The oxidation of HMF to FDCA over Au2Pd1@C800 [97]. (e) The oxidation of HMF to FDCA over Au2Pd1/C800 [97]. (f) The oxidation of HMF to FDCA over Au2Pd1/C800-Re [97]. (g) FDCA yield over Au2Pd1/C800, Au2Pd1/C800-Re, and Au2Pd1@C800 [97].
Figure 8. (a) Schematic diagram for the preparation of Pt@Beta [59]. (b) Adsorption amount of HMF, HMFCA, FFCA, and FDCA on 0.2% Pt@Beta [59]. (c) Adsorption amount of HMF, HMFCA, FFCA, and FDCA on 0.2% Pt/Beta [59]. (d) The oxidation of HMF to FDCA over Au2Pd1@C800 [97]. (e) The oxidation of HMF to FDCA over Au2Pd1/C800 [97]. (f) The oxidation of HMF to FDCA over Au2Pd1/C800-Re [97]. (g) FDCA yield over Au2Pd1/C800, Au2Pd1/C800-Re, and Au2Pd1@C800 [97].
Chemistry 07 00017 g008
Table 1. Reactivity of typical noble metal-based catalysts on the oxidation of HMF to FDCA.
Table 1. Reactivity of typical noble metal-based catalysts on the oxidation of HMF to FDCA.
CatalystSolution 1T/°CPO2/MPaReaction Time/hCon/%Sel/%Ref.
Pt2Ru-MgAlOalkali-free1000.22410099[54]
Pt1-Co@C-N41000.549999[56]
Pt-Cu1.5/ACalkali-free1501610099[57]
Co@Nb-Ptalkali-free1101.04100>99[58]
Pt@Beta690-24>9999[59]
Pt/Ni400c 2alkali-free1001.012100100[60]
Pt-Ca-Hie-ZSM-5 3alkali-free11022410080[61]
Pt/Fe3O4/rGOalkali-free950.5810098[62]
RuOx/MnOx-VCalkali-free1201.0610086[38]
Pt2Ru-MgAlOalkali-free1000.22410099[54]
Ru/MgOalkali-free1600.6410090[63]
Ru/MnCo2O4alkali-free1202.51010099[64]
Ru/Mn6Ce1OYalkali-free15011510099[65]
Au/Sn-Beta11401110098[48]
2Au/Mg-Beta-Ps11302.0495.098.1[66]
Au/Al2O32701410070[67]
Au4Pd1@SiTi2.61100.1247478[68]
PdAu@NC21000.5610099[69]
Au3Pd1/HRN5C41002.02410099[70]
1 The number shown in this column represents the OH−/HMF molar ratio in alkaline solution; 2 Ni(OH)2 was calcined at 400 °C; 3 alkaline exchange zeolite.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Guo, Y.; Zhao, Y.; Gao, S.; Lv, B.; Wu, Z. Noble Metal-Based Catalysts for Selective Oxidation of HMF to FDCA: Progress in Reaction Mechanism and Active Sites. Chemistry 2025, 7, 17. https://doi.org/10.3390/chemistry7010017

AMA Style

Guo Y, Zhao Y, Gao S, Lv B, Wu Z. Noble Metal-Based Catalysts for Selective Oxidation of HMF to FDCA: Progress in Reaction Mechanism and Active Sites. Chemistry. 2025; 7(1):17. https://doi.org/10.3390/chemistry7010017

Chicago/Turabian Style

Guo, Yingshuo, Yitong Zhao, Shiao Gao, Binhong Lv, and Zhijie Wu. 2025. "Noble Metal-Based Catalysts for Selective Oxidation of HMF to FDCA: Progress in Reaction Mechanism and Active Sites" Chemistry 7, no. 1: 17. https://doi.org/10.3390/chemistry7010017

APA Style

Guo, Y., Zhao, Y., Gao, S., Lv, B., & Wu, Z. (2025). Noble Metal-Based Catalysts for Selective Oxidation of HMF to FDCA: Progress in Reaction Mechanism and Active Sites. Chemistry, 7(1), 17. https://doi.org/10.3390/chemistry7010017

Article Metrics

Back to TopTop