Catalysts

30 pages, 6591 KiB

Open AccessArticle

In-Depth Study on Synergic Interactions and Thermo-Kinetic Analysis of (Wheat Straw and Woody Sawdust) Biomass Co-Pyrolysis over Mussel Shell-Derived CaO Catalyst Using Coats–Redfern Method

by Muhammad Saleem and Ali Bahadar

Catalysts 2024, 14(9), 655; https://doi.org/10.3390/catal14090655 - 23 Sep 2024

Viewed by 780

Abstract

The behavior of wheat straw biomass (WS), woody sawdust biomass (WB), and their blends during catalytic co-pyrolysis are analyzed in the presence of CaO catalyst, which is obtained from the calcination of mussel shells. Synergy analysis of blends and pure materials is measured [...] Read more.

The behavior of wheat straw biomass (WS), woody sawdust biomass (WB), and their blends during catalytic co-pyrolysis are analyzed in the presence of CaO catalyst, which is obtained from the calcination of mussel shells. Synergy analysis of blends and pure materials is measured by studying the difference between theoretical and experimental values of wt.%/min, (RL%), and (WL%), which correspond to maximum weight loss rate, residue left, and weight loss, respectively. The Coats–Redfern method is utilized for evaluating the thermo-kinetic properties. The chemical reaction order model F1 is the best model that describes the Ea of 60.05 kJ/mol and ∆H, ∆G, and ∆S values of 55.03 kJ/mol, 162.26 kJ/mol, and −0.18 kJ/mol.K, respectively, for the optimum blend 80WS−20WB, reducing the thermo-kinetic properties. Model D3 showed better results for the Ea, ∆H, ∆G, and ∆S for the 5% CaO blend, which certified the viability of co-pyrolysis of WS and WB, while DTG indicated that exothermic and endothermic reactions occur together. Full article

(This article belongs to the Section Biomass Catalysis)

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15 pages, 5659 KiB

Open AccessArticle

In Situ Metallic Bi-Modified (110)BiOBr Nanosheets with Surface Plasmon Resonance Effect for Enhancing Photocatalytic Performance Despite of Larger Optical Band Gap

by Yunhe Mu, Hongxue Chu, Hougang Fan, Xin Li, Xiaoyan Liu, Lili Yang, Maobin Wei and Huilian Liu

Catalysts 2024, 14(9), 654; https://doi.org/10.3390/catal14090654 - 23 Sep 2024

Viewed by 534

Abstract

BiOBr with different preferred growth orientation facets would show a different photocatalytic performance. When decorated in situ with metallic Bi nanoparticles, Bi/BiOBr would commonly display an enhanced photocatalytic performance. In this paper, the BiOBr nanoplates with preferred growth orientation (102) facet and (110) [...] Read more.

BiOBr with different preferred growth orientation facets would show a different photocatalytic performance. When decorated in situ with metallic Bi nanoparticles, Bi/BiOBr would commonly display an enhanced photocatalytic performance. In this paper, the BiOBr nanoplates with preferred growth orientation (102) facet and (110) facet were first synthesized using a hydrothermal method. Then, some metallic Bi nanoparticles were modified in situ onto the (110)BiOBr nanoplates, which was expected to show a much more enhanced photocatalytic performance. All samples were characterized using XRD, FE-SEM, TEM, N₂ adsorption–desorption, UV–vis and XPS. FE-SEM and TEM images showed that the grain size of the metallic Bi particles was about 5 nm to 10 nm. UV–vis spectra showed that, after some metallic Bi nanoparticles were modified on (110)BiOBr nanoplates, the light absorbance in the visible light region at 400–700 nm became stronger and their optical band gap became larger. N₂ adsorption–desorption tests showed that the Bi(x)/(110)BiOBr nanosheets possessed larger specific surface areas than that of the (102)BiOBr and (110)BiOBr nanoplates. The XPS results showed that Bi(x)/(110)BiOBr contained more oxygen vacancies and a more negative value of the conduction band minimum. The photocatalytic performance of (102)BiOBr, (110)BiOBr and Bi(x)/(110)BiOBr were tested in the photocatalytic degradation of rhodamine B under visible light irradiation for 2 h; their photocatalytic efficiency was 45%, 75% and 80%, respectively. In comparison to (102)BiOBr, (110)BiOBr exhibited much higher photocatalytic activity, while for Bi(x)/(110)BiOBr, despite the surface Plasmon resonance effect, a larger specific surface area and more oxygen vacancies, the enhancement of the efficiency was limited, which might have resulted from the larger optical band gap. Full article

(This article belongs to the Section Photocatalysis)

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18 pages, 2518 KiB

Open AccessArticle

Evaluation of Cobalt, Nickel, and Palladium Complexes as Catalysts for the Hydrogenation and Improvement of Oxidative Stability of Biodiesel

by Fortunate P. Sejie, Olayinka A. Oyetunji, Banothile C. E. Makhubela, James Darkwa and Nora H. de Leeuw

Catalysts 2024, 14(9), 653; https://doi.org/10.3390/catal14090653 - 23 Sep 2024

Viewed by 693

Abstract

Developing effective catalysts that can selectively hydrogenate C=C bonds in biodiesel samples is vital as it tackles the major problem of oxidative stability, which greatly limits the utilization of biodiesel as an alternative fuel. In this work, Co, Ni, and Pd catalysts stabilized [...] Read more.

Developing effective catalysts that can selectively hydrogenate C=C bonds in biodiesel samples is vital as it tackles the major problem of oxidative stability, which greatly limits the utilization of biodiesel as an alternative fuel. In this work, Co, Ni, and Pd catalysts stabilized with the bidentate nitrogen ligands N-(3-(triethoxysilyl)propyl)pyridin-2-ylmethylimine and N-(3-(triethoxysilyl)propyl)picolinamide were synthesized, characterized, and used as pre-catalysts in the transfer hydrogenation of C=C bonds in fatty acid methyl esters. The active catalysts from the Co, Ni, and Pd complexes sequentially hydrogenate the C18:2 chains to C18:1, which is further converted to C18:0 in the FAMEs of both methyl linoleate and jatropha biodiesel. The hydrogenation process was kinetically controlled, and after 3 h it yielded a biodiesel sample that contained 25.83% C16:0, 12.52% C18:2, 41.54% C18:1, 14.47% C18:0 and 3.0% C18:2 isomers. The un-hydrogenated jatropha diesel, hydrogenated jatropha diesel, and a B20 blend of jatropha were tested for susceptibility to oxidation reactions using the Rancimat method and FTIR spectroscopy, and the partial hydrogenation had improved the induction period by 3 h. Full article

(This article belongs to the Special Issue Novel Nanocatalysts for Sustainable and Green Chemistry)

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19 pages, 3991 KiB

Open AccessArticle

Diverse YqeK Diadenosine Tetraphosphate Hydrolases Control Biofilm Formation in an Iron-Dependent Manner

by Chie Ueda, Natalie Chin, Qianyi Yang, Luying Pan, Rheann Ponniah and Maria-Eirini Pandelia

Catalysts 2024, 14(9), 652; https://doi.org/10.3390/catal14090652 - 23 Sep 2024

Viewed by 680

Abstract

YqeK is a bacterial HD-domain metalloprotein that hydrolyzes the putative second messenger diadenosine tetraphosphate (Ap4A). Elevated Ap4A levels are primarily observed upon exposure of bacteria to factors such as heat or oxidative stress and cause pleiotropic effects, including antibiotic sensitivity and disrupted biofilm [...] Read more.

YqeK is a bacterial HD-domain metalloprotein that hydrolyzes the putative second messenger diadenosine tetraphosphate (Ap4A). Elevated Ap4A levels are primarily observed upon exposure of bacteria to factors such as heat or oxidative stress and cause pleiotropic effects, including antibiotic sensitivity and disrupted biofilm formation. Ap4A thus plays a central role in bacterial physiology and metabolism, and its hydrolysis by YqeK is intimately linked to the ability of these microbes to cope with stress. Although YqeK is reported to hydrolyze Ap4A under aerobic conditions, all four existing crystal structures reveal an active site that consists of a diiron center, portraying a cryptic chemical nature for the active metallocofactor. This study examines two YqeK proteins from two ecologically diverse parent organisms: the obligate anaerobe Clostridium acetobutylicum and the facultative aerobe Bacillus halodurans. Both enzymes utilize Fe-based cofactors for catalysis, while under ambient or oxidative conditions, Bh YqeK hydrolyzes Ap4A more efficiently compared to Ca YqeK. This redox-dependent activity difference stems from the following two molecular mechanisms: the incorporation of mixed-metal, Fe-based bimetallic cofactors, in which the second metal is redox inert (i.e., Fe–Zn) and the upshift of the Fe–Fe cofactor reduction potentials. In addition, three strictly conserved, positively charged residues vicinal to the active site are critical for tuning Ap4A hydrolysis. In conclusion, YqeK is an Fe-dependent phosphohydrolase that appears to have evolved to permit Ap4A hydrolysis under different environmental niches (aerobic vs. anaerobic) by expanding its cofactor configuration and O₂ tolerance. Full article

(This article belongs to the Special Issue The Design of Protein-Based Catalysts)

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11 pages, 1550 KiB

Open AccessArticle

A Spy Chemistry-Based Method for Purification of Proteins with Authentic N-Termini

by Xiaofeng Yang, Binrui Chen, Zisha Lao, Ya Xiang and Zhanglin Lin

Catalysts 2024, 14(9), 651; https://doi.org/10.3390/catal14090651 - 23 Sep 2024

Viewed by 949

Abstract

Protein purification is essential in life sciences and biomanufacturing. Tag-mediated protein affinity chromatography (AC) enables the preparation of recombinant proteins with medium to high purity. However, traditional AC methods often require expensive resins and additional tag removal steps. Here, we introduce a purification [...] Read more.

Protein purification is essential in life sciences and biomanufacturing. Tag-mediated protein affinity chromatography (AC) enables the preparation of recombinant proteins with medium to high purity. However, traditional AC methods often require expensive resins and additional tag removal steps. Here, we introduce a purification method for proteins with authentic N-termini based on reusable SpyDock-modified epoxy resin and a pH-inducible self-cleavage intein. This method was validated using SpyTag002-fused red fluorescent protein (RFP) and applied to purify three model proteins: glutathione S-transferase (GST), human growth hormone (hGH), and the nanobody caplacizumab, directly from cell lysates. The purified proteins achieved high purities (92–98%) and comparable yields to the commercial His-tag method. The preparation of the SpyDock-modified resin is straightforward, and SpyDock can be easily produced via standard Escherichia coli fermentation processes, making it potentially suitable for industrial-scale applications. Full article

(This article belongs to the Special Issue State-of-the-Art Enzyme Engineering and Biocatalysis in China)

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11 pages, 3445 KiB

Open AccessArticle

Exploring the Synthesis of Novel Sillenite Bi₁₂SnO₂₀: Effect of Calcination Temperature on the Phase Formation and Catalytic Performance

by Oussama Baaloudj, Hamza Kenfoud, Monica Brienza, Atef El Jery, Moutaz Aldrdery and Aymen Amin Assadi

Catalysts 2024, 14(9), 650; https://doi.org/10.3390/catal14090650 - 23 Sep 2024

Viewed by 1151

Abstract

Sillenite materials have been the focus of intense research in recent years due to their unique properties and distinct structure with the I23 space group. This electronic structure has reflected high-quality applications and results for some environmental processes such as photocatalysis. This paper [...] Read more.

Sillenite materials have been the focus of intense research in recent years due to their unique properties and distinct structure with the I23 space group. This electronic structure has reflected high-quality applications and results for some environmental processes such as photocatalysis. This paper investigates the synthesis of a new sillenite, Bi₁₂SnO_20, and its characteristics, emphasizing its potential for photocatalytic applications. The sillenite Bi₁₂SnO₂₀ has been synthesized through the co-precipitation method by mixing the appropriate ratio of Bi and Sn ions. The obtained particles after precipitation and drying were characterized by thermogravimetric analysis (TGA) and then calcined at different temperatures based on this analysis. The phase has been identified by structural analysis using X-ray diffraction (XRD), and its morphology after identification was carried out by scanning electron microscopy (SEM). The calcination temperature has been found to have a critical role in obtaining the phase, where the phase was found to be formed at temperatures between 310 and 400 °C and changed to other phases within higher temperatures. The physicochemical properties of this sillenite were also studied by Fourier-transform infrared spectroscopy (FTIR) and UV Visible Spectrometer (UV-Vis). To study the obtained phases at different calcination temperatures, performance testing was performed under visible light to remove different contaminants, which are Tetracycline, Bisphenol A, and Rhodamine B. The phase Bi₁₂SnO₂₀ obtained at 350 °C with a catalyst dose of 1 g/L showed the highest performance for removing these pollutants with concentrations of 20 mg/L, with an efficiency of almost 100% within 2 h. This work will be useful as an important resource and strategy for the development of this sillenite material in its pure phase. Full article

(This article belongs to the Special Issue Catalytic Energy Conversion and Catalytic Environmental Purification)

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16 pages, 2437 KiB

Open AccessArticle

Highly Efficient Degradation of 2-Methylisoborneol by Laccase Assisted by a Micro-Electric Field

by Ling Xu, Beidian Li, Tingting Liu, Anzhou Ma, Guoqiang Zhuang, Jingya Qian, Yi Cui, Shuhao Huo, Jiexiang Xia and Feng Wang

Catalysts 2024, 14(9), 649; https://doi.org/10.3390/catal14090649 - 23 Sep 2024

Viewed by 628

Abstract

Taste and odor (T&O) compounds have emerged as crucial parameters for assessing water quality. Therefore, identifying effective methodologies for the removal of these compounds is imperative. In this study, an effective approach utilizing laccase assisted by a micro-electric field was developed for the [...] Read more.

Taste and odor (T&O) compounds have emerged as crucial parameters for assessing water quality. Therefore, identifying effective methodologies for the removal of these compounds is imperative. In this study, an effective approach utilizing laccase assisted by a micro-electric field was developed for the degradation of 2-methylisoborneol (2-MIB). For this purpose, the optimal conditions for the laccase-catalyzed degradation of 2-MIB were determined, and they were pH 4.0, 25 °C, 150 rpm, 0.1 U/mL of laccase, and 200 ng/L of 2-MIB. Under these specified conditions, the degradation efficiency of 2-MIB was approximately 78% after a 4 h reaction period. Subsequently, the introduction of an electric field yielded a synergistic effect with the enzyme for 2-MIB degradation. At an electric current intensity of 0.04 A over a 4 h duration, the degradation efficiency increased to 90.78%. An analysis using SPME-GC/MS provided information on the degradation intermediates of 2-MIB resulting from laccase-catalyzed degradation, electrocatalytic degradation, and micro-electric-assisted laccase degradation. The potential degradation pathways of 2-MIB illustrated that these three methods result in common degradation products, such as capric aldehyde, nonylaldehyde, and 2-ethylhexanol, and their final products include 3-pentanone, acetone, and 2-butanone. This study provides an enzyme–electrochemical method for the efficient and rapid degradation and removal of 2-MIB. The strategy of laccase catalysis assisted by a micro-electric field has good potential for the removal of pollutants from the natural environment. Full article

(This article belongs to the Special Issue Design and Application of Combined Catalysis)

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15 pages, 6123 KiB

Open AccessArticle

Promoting Electricity Production and Cr (VI) Removal Using a Light–Rutile–Biochar Cathode for Microbial Fuel Cells

by Baoyin Sun, Wenqing Xie, Xiangwen Zhang, Yunzhu Zhou, Zhaolin Yang, Lei Wang, Jiqiang Zhou and Guiping Ren

Catalysts 2024, 14(9), 648; https://doi.org/10.3390/catal14090648 - 22 Sep 2024

Viewed by 1164

Abstract

Microbial fuel cell (MFC) technology holds significant promise for the production of clean energy and treatment of pollutants. Nevertheless, challenges such as low power generation efficiency and the high cost of electrode materials have impeded its widespread adoption. The porous microstructure of biochar [...] Read more.

Microbial fuel cell (MFC) technology holds significant promise for the production of clean energy and treatment of pollutants. Nevertheless, challenges such as low power generation efficiency and the high cost of electrode materials have impeded its widespread adoption. The porous microstructure of biochar and the exceptional photocatalytic properties of rutile endow it with promising catalytic potential. In this investigation, we synthesized a novel Rutile–Biochar (Rut-Bio) composite material using biochar as a carrier and natural rutile, and explored its effectiveness as a cathode catalyst to enhance the power generation efficiency of MFCs, as well as its application in remediating heavy metal pollution. Furthermore, the impact of visible light conditions on its performance enhancement was explored. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) analysis validated the successful fabrication of rutile composites loaded with biochar. The maximum current density and power density achieved by the MFCs were 153.9 mA/m² and 10.44 mW/m², respectively, representing a substantial increase of 113.5% and 225% compared to the control group. In addition, biochar-supported rutile MFCs showed excellent degradation performance of heavy metal pollutants under light conditions. Within 7 h, the Cr⁶⁺ degradation rate reached 95%. In contrast to the blank control group, the removal efficiency of pollutants exhibited increases of 630.8%. The cyclic degradation experiments also showcased the remarkable stability of the system over multiple cycles. This study successfully integrated natural rutile and biochar to fabricate highly efficient cathode photocatalyst composites, which not only enhanced the power generation performance of MFCs but also presented an environmentally sustainable and economically viable method for addressing heavy metal pollution. Full article

(This article belongs to the Special Issue Environmental Catalysis: Special Topic on Microbial Fuel Cell and Wastewater Treatment)

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17 pages, 1492 KiB

Open AccessArticle

Comparative Studies on Methyl Ester Production from Pretreated Sludge Palm Oil Using Homogeneous and Heterogeneous Base Catalysts

by Ye Min Oo, Panupong Juera-Ong, Kritsakon Pongraktham and Krit Somnuk

Catalysts 2024, 14(9), 647; https://doi.org/10.3390/catal14090647 - 22 Sep 2024

Viewed by 1027

Abstract

A heterogeneous base catalyst transesterification process with a calcium oxide (CaO) catalyst was performed to produce high-purity methyl ester (ME) from pretreated sludge palm oil (PSPO) derived from sludge palm oil (SPO). Additionally, a comparative analysis was conducted with potassium hydroxide (KOH) as [...] Read more.

A heterogeneous base catalyst transesterification process with a calcium oxide (CaO) catalyst was performed to produce high-purity methyl ester (ME) from pretreated sludge palm oil (PSPO) derived from sludge palm oil (SPO). Additionally, a comparative analysis was conducted with potassium hydroxide (KOH) as a homogeneous base catalyst to assess the distinctions between heterogeneous and homogeneous base catalysts. The response surface methodology (RSM) was utilized to determine the optimal and recommended conditions for both transesterification processes. For heterogeneous transesterification, a varying CaO catalyst loading (10–60 wt.%), methanol (25–65 wt.%), and reaction time (60–180 min) were essential parameters. Meanwhile, homogeneous transesterification involved investigating the KOH catalyst loading (1–3 wt.%), methanol (1.8–5.5 wt.%), and reaction time (20–60 min). For the heterogeneous-base-catalyzed reaction, the recommended conditions were as follows: a molar ratio of methanol to oil of 5.83:1 (41.61 wt.%), 31.3 wt.% CaO, and a reaction time of 119.0 min, which resulted in a ME purity of 96.51 wt.%. The optimal conditions for homogeneous transesterification were a molar ratio of methanol to oil of 0.49:1 (3.45 wt.%), a 40 min reaction time, and a 1.39 wt.% KOH concentration, which achieved 96.59 wt.% ME and met the standard. Full article

(This article belongs to the Section Catalysis in Organic and Polymer Chemistry)

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30 pages, 17190 KiB

Open AccessArticle

Synthesis, Performance Measurement of Dy₂EuSbO₇/ZnBiDyO₄ Heterojunction Composite Catalyst and Photocatalytic Degradation of Chlorpyrifos within Pesticide Wastewater under Visible Light Irradiation

by Jingfei Luan, Yang Xiao, Liang Hao, Ye Yao, Bowen Niu, Guangmin Yang and Yichun Wang

Catalysts 2024, 14(9), 646; https://doi.org/10.3390/catal14090646 - 21 Sep 2024

Viewed by 884

Abstract

For the first time, a novel catalyst named Dy₂EuSbO₇ was successfully synthesized via the high-temperature solid-state sintering method (HTSSM). Dy₂EuSbO₇/ZnBiDyO₄ heterojunction photocatalyst (DZHP) was fabricated through the HTSSM for degrading chlorpyrifos (CPS) in the pesticide [...] Read more.

For the first time, a novel catalyst named Dy₂EuSbO₇ was successfully synthesized via the high-temperature solid-state sintering method (HTSSM). Dy₂EuSbO₇/ZnBiDyO₄ heterojunction photocatalyst (DZHP) was fabricated through the HTSSM for degrading chlorpyrifos (CPS) in the pesticide wastewater under visible light irradiation (VSLID). Under VSLID, DZHP could effectively degrade CPS in pesticide wastewater. The experimental outcomes suggested that the kinetic curve with the Dy₂EuSbO₇/ZnBiDyO₄ heterojunction (DZH) as a photocatalyst for the reduction of CPS under VSLID conformed to the first-order kinetics (FOKT). After VSLID of 156 min, the photocatalytic degradation (PTD) removal rate of CPS using DZH as photocatalyst was 1.12 times, 1.21 times, or 2.96 times that using Dy₂EuSbO₇ as a photocatalyst, ZnBiDyO₄ as a photocatalyst, or nitrogen-doped titanium dioxide as a photocatalyst. After VSLID of 156 min for four cycle degradation tests (FCDTS) with DZH as a photocatalyst, the removal rate of CPS reached 98.78%, 97.66%, 96.59%, and 95.69%, respectively. Above results indicated that the DZHP possessed high stability. Experiments with the addition of trapping agents showed that hydroxyl radicals (•OH) owned the strongest oxidative removal ability for degrading CPS compared with superoxide anions (•O₂⁻) or holes (h⁺). The oxidation capacity of three oxidation radicals for eliminating CPS was ranked in the ascending order as follows: h⁺ < •OH < •O₂⁻. Lastly, the possible degradation pathway and degradation mechanism of CPS were discussed in detail. A visible light responsive heterojunction catalyst with high catalytic activity and a photocatalytic reaction system which were capable of efficiently removing toxic organic pollutants from pesticide wastewater were obtained. Full article

(This article belongs to the Section Photocatalysis)

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15 pages, 8013 KiB

Open AccessFeature PaperArticle

Shining a Light on Sewage Treatment: Building a High-Activity and Long-Lasting Photocatalytic Reactor with the Elegance of a “Kongming Lantern”

by Xiaohan Xu, Yi Wang, Zhuo Deng, Jin Wang, Xile Wei, Peng Wang and Dun Zhang

Catalysts 2024, 14(9), 645; https://doi.org/10.3390/catal14090645 - 21 Sep 2024

Viewed by 545

Abstract

Photocatalysis is a promising technology for efficient sewage treatment, and designing a reactor with a stable loading technique is crucial for achieving long-term stability. However, there is a need to improve the current state of the art in both reactor design and loading [...] Read more.

Photocatalysis is a promising technology for efficient sewage treatment, and designing a reactor with a stable loading technique is crucial for achieving long-term stability. However, there is a need to improve the current state of the art in both reactor design and loading techniques to ensure reliable and efficient performance. In this study, we propose an innovative solution by employing polydimethylsiloxane as a bonding layer on a substrate of 3D-printed polyacrylic resin. By means of mechanical extrusion, the active layer interacts with the bonding layer, ensuring a stable loading of the active layer onto the substrate. Simultaneously, 3D printing technology is utilized to construct a photocatalytic reactor resembling a “Kongming Lantern”, guaranteeing both high activity and durability. The reactor exhibited remarkable performance in degrading organic dyes and eliminating microbes and displayed a satisfactory purification effect on real water samples. Most significantly, it maintained its catalytic activity even after 50 weeks of cyclic degradation. This study contributes to the development of improved photocatalysis technologies for long-term sewage treatment applications. Full article

(This article belongs to the Special Issue Catalysts for Water and Air Pollution Control: Present and Future, 2nd Edition)

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12 pages, 2397 KiB

Open AccessArticle

Kinetic Evaluation and Catalytic Efficiency of Sebacic Acid as a Novel Catalyst in Hydrogen Generation via NaBH₄ Alcoholysis Reactions

by Savas Gurdal

Catalysts 2024, 14(9), 644; https://doi.org/10.3390/catal14090644 - 20 Sep 2024

Viewed by 586

Abstract

This study explores the use of sebacic acid, a catalyst not previously examined in the literature, for hydrogen production from NaBH₄ through methanolysis and ethanolysis reactions. Solutions of sebacic acid with concentrations ranging from 0.1 M to 0.4 M were prepared and [...] Read more.

This study explores the use of sebacic acid, a catalyst not previously examined in the literature, for hydrogen production from NaBH₄ through methanolysis and ethanolysis reactions. Solutions of sebacic acid with concentrations ranging from 0.1 M to 0.4 M were prepared and tested. At a concentration of 0.3 M, 90% of the hydrogen from a 0.33 M NaBH₄ solution was released within 3 s, and full release was achieved in 4 s. Hydrogen production rates reached 4500 mL/min for ethanolysis and 4845 mL/min for methanolysis, with methanolysis reactions proving faster. The activation energies for methanolysis and ethanolysis were calculated as 7.17 kJ/mol and 52.3 kJ/mol, respectively. These results demonstrate that sebacic acid enables rapid and efficient hydrogen production, offering a new approach that significantly advances current hydrogen production methods. Full article

(This article belongs to the Special Issue Advanced Catalysis for Green Fuel Synthesis and Energy Conversion, 2nd Edition)

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14 pages, 2231 KiB

Open AccessArticle

Biodiesel Synthesis from Date Seed Oil Using Camel Dung as a Novel Green Catalyst: An Experimental Investigation

by Raiedhah A. Alsaiari, Esraa M. Musa and Moustafa A. Rizk

Catalysts 2024, 14(9), 643; https://doi.org/10.3390/catal14090643 - 20 Sep 2024

Viewed by 1024

Abstract

Biodiesel is seen as more environmentally benign than petroleum-based fuels. It is also cheaper and capable of creating cleaner energy, which has a good impact on increasing the bioeconomy. An investigation was conducted on a novel heterogeneous catalyst system utilized in the synthesis [...] Read more.

Biodiesel is seen as more environmentally benign than petroleum-based fuels. It is also cheaper and capable of creating cleaner energy, which has a good impact on increasing the bioeconomy. An investigation was conducted on a novel heterogeneous catalyst system utilized in the synthesis of eco-friendly biodiesel from date seed oil, a non-edible feedstock obtained through the calcination of desiccated camel manure at varying temperatures. X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) analysis, and scanning electron microscopy (SEM) were utilized to characterize this catalyst. As a result of raising the calcination temperature, the results showed that the pore size of the catalyst decreased. The biodiesel production was optimized to be 86% by using the transesterification method. The optimal reaction parameters included a catalyst with 4% loading, a molar ratio of 1:8 between date seed oil and ethanol, and a temperature of 75 °C for a reaction period of three hours. The confirmation of FAME generation was achieved by gas chromatography–mass spectrometry (GC–MS). The fuel qualities of fatty acid ethyl ester are in accordance with ASTM, suggesting that it is a suitable alternative fuel option. Utilizing biodiesel derived from waste and untamed resources to establish and execute a more sustainable and ecologically conscious energy plan is praiseworthy. The adoption and integration of green energy practices could potentially yield positive environmental outcomes, thereby fostering enhanced societal and economic development for the biodiesel sector on a broader scale. Full article

(This article belongs to the Special Issue Catalytic Conversion of Biomass to Chemicals)

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4 pages, 179 KiB

Open AccessEditorial

Advances in Catalytic Oxidation of Methane and Carbon Monoxide (2nd Edition)

by Hongxing Dai and Junhu Wang

Catalysts 2024, 14(9), 642; https://doi.org/10.3390/catal14090642 - 20 Sep 2024

Viewed by 810

Abstract

The catalytic removal of carbon monoxide and methane produced from human activities is an important method for eliminating these pollutants, and can solve their associated environmental problems [...] Full article

(This article belongs to the Special Issue Advances in Catalytic Oxidation of Methane and Carbon Monoxide, 2nd Edition)

21 pages, 9630 KiB

Open AccessArticle

Enhancing Biomedical and Photocatalytic Properties: Synthesis, Characterization, and Evaluation of Copper–Zinc Oxide Nanoparticles via Co-Precipitation Approach

by Maha M. Almoneef, Manal A. Awad, Haia H. Aldosari, Awatif A. Hendi, Horiah A. Aldehish, Nada M. Merghani, Saad G. Alshammari, Latifah M. Alsuliman, Alhanouf A. Alghareeb and Magd S. Ahmed

Catalysts 2024, 14(9), 641; https://doi.org/10.3390/catal14090641 - 20 Sep 2024

Viewed by 745

Abstract

In this work, researchers synthesized copper–zinc oxide nanoparticles (NPs) of different shapes and sizes and tested their antibacterial and anticancer effects. The current research used a straightforward method to synthesize copper-doped zinc oxide nanoparticles (Cu-ZnO NPs). Next, the photocatalytic, antibacterial, and anticancer properties [...] Read more.

In this work, researchers synthesized copper–zinc oxide nanoparticles (NPs) of different shapes and sizes and tested their antibacterial and anticancer effects. The current research used a straightforward method to synthesize copper-doped zinc oxide nanoparticles (Cu-ZnO NPs). Next, the photocatalytic, antibacterial, and anticancer properties of the Cu-ZnO NPs were ascertained. Nanoparticles of Cu-doped ZnO were synthesized using co-precipitation technology. The physicochemical characterization was carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet–visible (UV-Vis) and Fourier-transform infrared (FTIR) spectroscopy, and other imaging techniques. The SEM analysis confirmed that the particles observed by SEM were found to be below 100 nm in size, which aligns with the results obtained from XRD. The size histogram in the figure inset shows that the nanoparticles are mostly round and have a size range of 5 to 50 nm. The XRD diffractograms revealed the classic structure of wurtzite-phase crystalline Cu-ZnO, and the crystallite size is 26.48 nm. Differences in the principal absorption peaks between the FTIR and UV-vis spectra suggest that varying ZnO NP morphologies might lead to spectrum shifts. We used the agar diffusion method to determine how effective Cu-doped ZnO NPs were against bacteria and the MTT assay to see how well they worked against cancer. The photocatalytic disintegration capacity of Cu-doped ZnO NPs was investigated by degrading crystal violet (CV) and methylene blue (MB) dyes under ultraviolet lamp irradiation. A value of 1.32 eV was recorded for the band gap energy. All peaks conformed to those of the Zn, O, and Cu atoms, and there were no impurities, according to the EDS study. Additionally, the nanoparticles had anticancer properties, indicating that the NPs were specifically targeting cancer cells by inducing cell death. At a 100 µg/mL concentration of the synthesized Cu-doped ZnO NPs, the cell availability percentages for the SW480, MDA-231, and HeLa cell lines were 29.55, 30.15, and 28.2%, respectively. These findings support the idea that Cu-doped ZnO NPs might be a new cancer treatment. Moreover, the results show the percentage of dye degradation over different time durations. After 180 h, the degradation of CV dye reached 79.6%, while MB dye exhibited a degradation of 69.9%. Based on these findings, Cu-doped ZnO NPs have the potential to be effective photocatalysts, antibacterial agents, and cancer fighters. This bodes well for their potential applications in the fields of ecology, medicine, and industry in the future. Full article

(This article belongs to the Special Issue Cutting-Edge Photocatalysis)

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4 pages, 409 KiB

Open AccessEditorial

New Catalysts and Reactors for the Synthesis or Conversion of Methanol

by Jaime Soler

Catalysts 2024, 14(9), 640; https://doi.org/10.3390/catal14090640 - 20 Sep 2024

Viewed by 1273

Abstract

Energy storage is a critical issue in the development of an economy based on the use of renewable energy [...] Full article

(This article belongs to the Special Issue New Catalysts and Reactors for the Synthesis or Conversion of Methanol)

16 pages, 6912 KiB

Open AccessArticle

Enhanced Photoelectrochemical Water Splitting Performance of Ce-Doped TiO₂ Nanorod Array Photoanodes for Efficient Hydrogen Production

by Bi-Li Lin, Rui Chen, Mei-Ling Zhu, Ao-Sheng She, Wen Chen, Bai-Tong Niu, Yan-Xin Chen and Xiu-Mei Lin

Catalysts 2024, 14(9), 639; https://doi.org/10.3390/catal14090639 - 20 Sep 2024

Viewed by 1081

Abstract

In this study, original titanium dioxide (TiO₂) and cerium (Ce)-doped TiO₂ nanorod array photoanodes are prepared by hydrothermal method combined with high-temperature annealing, and their morphology, photoelectrochemical properties, and photocatalytic hydrogen production ability are systematically evaluated. X-ray diffraction (XRD) analysis [...] Read more.

In this study, original titanium dioxide (TiO₂) and cerium (Ce)-doped TiO₂ nanorod array photoanodes are prepared by hydrothermal method combined with high-temperature annealing, and their morphology, photoelectrochemical properties, and photocatalytic hydrogen production ability are systematically evaluated. X-ray diffraction (XRD) analysis shows that as the Ce content increases, the diffraction peak of the rutile phase (110) shifts towards lower angles, indicating the successful doping of different contents of Ce into the TiO₂ lattice. Photoelectric performance test results show that Ce doping significantly improves the photocurrent density of TiO₂, especially for the 0.54wt% Ce-doped TiO₂ (denoted as CR5). The photocurrent density of CR5 reaches 1.98 mA/cm² at a bias voltage of 1.23 V (relative to RHE), which is 2.6 times that of undoped TiO₂ (denoted as R). Photoelectrochemical hydrolysis test results show that the hydrogen yield performance under full-spectrum testing conditions of Ce-doped TiO₂ photoanodes is better than that of original TiO₂ as well, which are 37.03 and 12.64 µmol·cm⁻²·h⁻¹ for CR5 and R, respectively. These results indicate that Ce doping can effectively promote charge separation and improve hydrogen production efficiency by reducing resistance, accelerating charge transfer, and introducing new electronic energy levels. Our findings provide a new strategy for designing efficient photocatalysts with enhanced photoelectrochemical (PEC) water-splitting performance. Full article

(This article belongs to the Section Photocatalysis)

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12 pages, 2130 KiB

Open AccessFeature PaperArticle

Superhydrophobic Surface Modification of a Co-Ru/SiO₂ Catalyst for Enhanced Fischer-Tropsch Synthesis

by Pawarat Bootpakdeetam, Oluchukwu Virginia Igboenyesi, Brian H. Dennis and Frederick M. MacDonnell

Catalysts 2024, 14(9), 638; https://doi.org/10.3390/catal14090638 - 19 Sep 2024

Viewed by 947

Abstract

Commercial silica support pellets were impregnated and calcined to contain cobalt oxide and ruthenium oxide for Fischer-Tropsch synthesis (FTS). The precatalyst pellets were split evenly into two groups, the control precatalyst (c-precat) and silylated precatalyst (s-precat), which were treated with 1H,1H, 2H, 2H-perfluorooctyltriethoxysilane [...] Read more.

Commercial silica support pellets were impregnated and calcined to contain cobalt oxide and ruthenium oxide for Fischer-Tropsch synthesis (FTS). The precatalyst pellets were split evenly into two groups, the control precatalyst (c-precat) and silylated precatalyst (s-precat), which were treated with 1H,1H, 2H, 2H-perfluorooctyltriethoxysilane (PFOS) in toluene. The samples of powderized s-precat were superhydrophobic, as determined by the water droplet contact angle (>150°) and sliding angle (<1°). Thermal analysis revealed the PFOS groups to be thermally stable up to 400 °C and temperature programmed reduction (TPR) studies showed that H₂ reduction of the cobalt oxide to cobalt was enhanced at lower temperatures relative to the untreated c-precat. The two active catalysts were examined for their FTS performance in a tubular fixed-bed reactor after in situ reduction at 400 °C for 16 h in flowing H₂ to give the active catalysts c-cat and s-cat. The FTS runs were performed under identical conditions (255 °C, 2.1 MPa, H₂/CO = 2.0, gas hourly space velocity (GHSV) 510 h^–1) for 5 days. Each catalyst was examined in three runs (n = 3) and the mean values with error data are reported. S-cat showed a higher selectivity for C₅₊ products (64 vs. 54%) and lower selectivity for CH₄ (11 vs. 17%), CO₂ (2 % vs. 4 %), and olefins (8% vs. 15%) than c-cat. S-cat also showed higher CO conversion, at 37% compared to 26%, leading to a 64% increase in the C₅₊ productivity measured as g C₅₊ products per g catalyst per hour. An analysis of the temperature differential between the catalyst bed and external furnace temperature showed that s-cat was substantially more active (DT_initial = 29 °C) and stable over the 5-day run (DT_final = 22 °C), whereas the attenuated activity of c-cat (DT_initial = 16 °C) decayed steadily over 3 days until it was barely active (DT_final < 5 °C). A post-run surface analysis of s-cat revealed no change in the water contact angle or sliding angle, indicating that the FTS operation did not degrade the PFOS surface treatment. Full article

(This article belongs to the Special Issue Catalysis for Selective Hydrogenation of CO and CO₂, 2nd Edition)

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18 pages, 5834 KiB

Open AccessArticle

Hydrogen-Ignited-Methanol Catalytic Co-Combustion of Aromatic Volatile Organic Compounds over PdPt/Al₂O₃ Bimetallic Catalyst

by Sehrish Munsif, Lutf Ullah, Long Cao, Palle Ramana Murthy, Jing-Cai Zhang and Wei-Zhen Li

Catalysts 2024, 14(9), 637; https://doi.org/10.3390/catal14090637 - 19 Sep 2024

Viewed by 684

Abstract

Electric heating is frequently employed to treat volatile organic compounds (VOCs) through catalytic combustion. However, it is associated with problems such as slow heating, high energy consumption, and low efficiency. This study explores PdPt/Al₂O₃ catalysts for igniting methanol (MeOH) through [...] Read more.

Electric heating is frequently employed to treat volatile organic compounds (VOCs) through catalytic combustion. However, it is associated with problems such as slow heating, high energy consumption, and low efficiency. This study explores PdPt/Al₂O₃ catalysts for igniting methanol (MeOH) through H₂ catalytic combustion, providing internal on-site heating of catalyst active sites. It also investigates VOCs’ abatement using H₂-ignited-MeOH combustion without H₂ and external heating. Bimetallic catalysts enhance activity and reduce thermal aging. Hydrogen gas (H₂) can initiate the MeOH combustion at room temperature with the addition of very small amounts, even below its low explosive limit of 4%. This process optimizes MeOH ignition at approximately 350 °C, even when the concentration of H₂ is as low as 0.01%. This method enhances combustion kinetics, converting MeOH and VOCs into CO₂ and water. Catalytic performance is independent of PdPt nanoparticle sizes in fresh and spent catalysts, represented in XRD and STEM. Using hydrogen as an igniting agent provides a clean, effective method to initiate catalytic reactions, addressing traditional challenges and enhancing VOCs’ decomposition efficiency. Full article

(This article belongs to the Special Issue Effect of the Modification of Catalysts on the Catalytic Performance, 2nd Edition)

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32 pages, 6561 KiB

Open AccessReview

Recent Research Progress on Surface Modified Graphite Carbon Nitride Nanocomposites and Their Photocatalytic Applications: An Overview

by Shuhan Li, Juntao Tan, Jiatong Liu, Yang Li, Liang Sun, Zhijie Huang and Jiaming Li

Catalysts 2024, 14(9), 636; https://doi.org/10.3390/catal14090636 - 19 Sep 2024

Viewed by 1006

Abstract

Semiconductors with visible light catalytic characteristics can realize the degradation of pollutants, CO₂ reduction, and hydrogen preparation in sunlight. They have huge application value in the fields of environmental repair and green energy. Graphite phase nitride (g-C₃N₄, CN) [...] Read more.

Semiconductors with visible light catalytic characteristics can realize the degradation of pollutants, CO₂ reduction, and hydrogen preparation in sunlight. They have huge application value in the fields of environmental repair and green energy. Graphite phase nitride (g-C₃N₄, CN) is widely used in various fields such as photocatalytic degradation of pollutants due to its suitable gap width, easy preparation, low cost, fast visible light response, and rich surface activity sites. However, the absorption rate of ordinary CN on visible light is low, and the carriers are easy to recombination, making the lower optical catalytic activity. Therefore, in order to improve the photocatalytic characteristics of the CN, it is necessary to make the surface modification. This article first introduces several main methods for the current surface modification of CN, including size regulation, catalyst embedding, defect introduction, heterostructure construction, etc., and then summarizes the optical catalytic application and related mechanisms of CN. Finally, some challenges and development prospects of CN in preparation and photocatalytic applications are proposed. Full article

(This article belongs to the Special Issue Two-Dimensional Materials in Photo(electro)catalysis)

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10 pages, 2078 KiB

Open AccessArticle

Microwave-Assisted Oxidation of N₂ into NO_x over a La-Ce-Mn-O Perovskite Yielding Plasmas in a Quartz Flow Reactor at Atmospheric Pressure

by Frederic C. Meunier and Akim Kaddouri

Catalysts 2024, 14(9), 635; https://doi.org/10.3390/catal14090635 - 19 Sep 2024

Viewed by 812

Abstract

N₂ oxidation to NO_x is a challenging reaction, and alternative routes to the industrial Ostwald process are of interest. A perovskite under flowing O₂-N₂ mixtures at atmospheric pressure in a quartz tube reactor was irradiated by microwaves (MW), [...] Read more.

N₂ oxidation to NO_x is a challenging reaction, and alternative routes to the industrial Ostwald process are of interest. A perovskite under flowing O₂-N₂ mixtures at atmospheric pressure in a quartz tube reactor was irradiated by microwaves (MW), leading to the formation of hot spots and plasmas within the catalyst bed. NO_x concentrations up to 2.5 vol.% in one pass were obtained at 600 W. Using a lower MW power of 100 W led to a pulsed mode yielding lower NO_x concentrations and no noticeable damage to the quartz reactor. The formation of plasma was strongly dependent on the perovskite bed packing. The perovskite acted primarily as a susceptor and likely also as a catalyst, although the proportion of heterogeneous and homogenous reactions could not be determined in the present study. The simple reactor layout allowing operation at atmospheric pressure is promising for the development of practical MW-assisted N₂ fixation technologies. Full article

(This article belongs to the Section Catalysis for Sustainable Energy)

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13 pages, 3743 KiB

Open AccessArticle

Deactivation of Cu/ZSM-5 Catalysts during the Conversion of 2,3-Butanediol to Butenes

by Ziyuan Wang, Pawel Chmielniak and Carsten Sievers

Catalysts 2024, 14(9), 634; https://doi.org/10.3390/catal14090634 - 19 Sep 2024

Viewed by 866

Abstract

This work determines the deactivation mechanisms of Cu/ZSM-5 catalysts used for the conversion of 2,3-butanediol to butene as part of an alcohol-to-jet route. The deactivation of the catalyst, reflected by a drop in the rate of the limiting hydrogenation step by over 90% [...] Read more.

This work determines the deactivation mechanisms of Cu/ZSM-5 catalysts used for the conversion of 2,3-butanediol to butene as part of an alcohol-to-jet route. The deactivation of the catalyst, reflected by a drop in the rate of the limiting hydrogenation step by over 90% in 24 h at a weight hourly space velocity of 5.92 h⁻¹, proceeds via both the agglomeration of copper particles and the obstruction of copper surfaces due to carbonaceous deposits, although the former has less impact on the decrease in the hydrogenation rate. To reduce the detrimental effect of carbonaceous deposits on catalytic activity, ZMS-5 is modified through desilication of the HZSM-5 support with NaOH and CsOH solutions to generate a hierarchical structure with mesopores. The catalyst with the CsOH-treated support generates the highest overall yield of desired olefin products and experiences the slowest deactivation. This is a result of the lower Brønsted acidity and larger mesopores found in the CsOH-treated catalyst, leading to the slower formation of carbonaceous deposits and the faster diffusion of their precursors out of the pores. Full article

(This article belongs to the Special Issue Zeolites and Zeolite-Based Catalysis)

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14 pages, 4880 KiB

Open AccessArticle

Enhancement Study of the Photoactivity of TiO₂ Photocatalysts during the Increase of the WO₃ Ratio in the Presence of Ag Metal

by Sharah H. Aldirham, Ahmed Helal, Mohd Shkir, M. A. Sayed and Atif Mossad Ali

Catalysts 2024, 14(9), 633; https://doi.org/10.3390/catal14090633 - 18 Sep 2024

Cited by 1 | Viewed by 666

Abstract

Nanocomposites (NCs) consisting of 4%Ag/x%WO₃/TiO₂, with varied concentrations (x = 1, 3, 5, 7 wt.%) of WO₃, were successfully synthesized using the sol-gel process to examine their photocatalytic performance. The synthesized 4%Ag/x%WO [...] Read more.

Nanocomposites (NCs) consisting of 4%Ag/x%WO₃/TiO₂, with varied concentrations (x = 1, 3, 5, 7 wt.%) of WO₃, were successfully synthesized using the sol-gel process to examine their photocatalytic performance. The synthesized 4%Ag/x%WO₃/TiO₂ nanopowder was characterized using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectra (UV–vis DRS), photoluminescence (PL), and Brunauer–Emmett–Teller (BET) surface area analysis to elucidate its physicochemical properties. The photocatalytic evaluation revealed that the Ag/1%WO₃/TiO₂ nanocomposite exhibits 98% photoreduction efficiency for Cr(VI) after 2 h under visible light due to the impact of the plasmonic effect of Ag atoms. In addition, the Ag/4%WO₃/TiO₂ shows about 95% photooxidation efficiency for methylene blue (MB) dye after 4 h. Full article

(This article belongs to the Special Issue Cutting-Edge Photocatalysis)

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14 pages, 2131 KiB

Open AccessArticle

Influence of Current Collector Design and Combination on the Performance of Passive Direct Methanol Fuel Cells

by Weibin Yu, Zhiyuan Xiao, Weiqi Zhang, Qiang Ma, Zhuo Li, Xiaohui Yan, Huaneng Su, Lei Xing and Qian Xu

Catalysts 2024, 14(9), 632; https://doi.org/10.3390/catal14090632 - 18 Sep 2024

Viewed by 625

Abstract

In this work, an anode current collector with a scaled step-hole structure (called SF-type) and a cathode current collector with a perforated cross-tilt structure (called X-type) were designed and fabricated for application in passive direct methanol fuel cells (DMFCs). A whole-cell test showed [...] Read more.

In this work, an anode current collector with a scaled step-hole structure (called SF-type) and a cathode current collector with a perforated cross-tilt structure (called X-type) were designed and fabricated for application in passive direct methanol fuel cells (DMFCs). A whole-cell test showed that the combination of an anode SF-type current collector and cathode conventional current collector increased the optimal methanol concentration from 6 M to 8 M and the maximum power density to 5.40 mW cm⁻², which improved the cell performance by 51.6% compared to that of the conventional design under ambient testing conditions. The combination of the anode conventional current collector and cathode X-type current collector achieved a maximum power density of 5.65 mW cm⁻² with a 58.7% performance improvement, while the optimal methanol concentration was increased to 10 M. Furthermore, the combination of anode SF-type and cathode X-type obtained the highest power density at 6.22 mW cm⁻². Notably, the anode and cathode catalyst loadings used in this study were 2.0 mg cm⁻², which is lower than the commonly used loading, thus reducing the fuel cell cost. Full article

(This article belongs to the Special Issue Advances in Catalyst Design and Application for Fuel Cells)

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18 pages, 5608 KiB

Open AccessArticle

Production of Bio-Oil from Sugarcane Bagasse through Hydrothermal Liquefaction Processes with Modified Zeolite Socony Mobil-5 Catalyst

by Thandiswa Jideani, Ntalane Sello Seroka and Lindiwe Khotseng

Catalysts 2024, 14(9), 631; https://doi.org/10.3390/catal14090631 - 18 Sep 2024

Viewed by 816

Abstract

In response to the increasing global demand for sustainable energy alternatives, this research explores the efficient conversion of sugarcane bagasse to bio-oil through hydrothermal liquefaction (HTL) processes with modified Zeolite Socony Mobil-5 catalysts (ZSM-5). The study systematically investigates the impact of feedstock quantity, [...] Read more.

In response to the increasing global demand for sustainable energy alternatives, this research explores the efficient conversion of sugarcane bagasse to bio-oil through hydrothermal liquefaction (HTL) processes with modified Zeolite Socony Mobil-5 catalysts (ZSM-5). The study systematically investigates the impact of feedstock quantity, reaction temperature, duration, and catalyst loading on bio-oil yield and quality. Optimisation experiments revealed that a feedstock amount of 10 grammes, an HTL temperature of 340 °C for 60 min and a ZSM-5 catalyst loading of 3 grammes resulted in the highest bio-oil yield. Furthermore, the introduction of Ni and Fe metals to ZSM-5 exhibited enhanced catalytic activity without compromising the structure of the zeolites. Comprehensive characterisation of modified catalysts using SEM-EDS, XRD, TGA, TEM, and FTIR provided insight into their structural and chemical properties. The successful incorporation of Ni and Fe into ZSM-5 was confirmed, highlighting promising applications in hydrothermal liquefaction. Gas chromatography–mass spectrometry (GC-MS) analysis of bio-oils demonstrated the effectiveness of the 2% Fe/ZSM-5 catalyst, highlighting a significant increase in hydrocarbon content. FTIR analysis of the produced bio-oils indicated a reduction in functional groups and intensified aromatic peaks, suggesting a shift in chemical composition favouring aromatic hydrocarbons. This study provides valuable information on HTL optimisation, catalyst modification, and bio-oil characterisation, advancing the understanding of sustainable biofuel production. The findings underscore the catalytic prowess of modified ZSM-5, particularly with iron incorporation, in promoting the formation of valuable hydrocarbons during hydrothermal liquefaction. Full article

(This article belongs to the Section Catalytic Reaction Engineering)

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14 pages, 4307 KiB

Open AccessArticle

PEDOT: PSS Doped Activated Biochar as a Novel Composite Material for Photocatalytic and Efficient Energy Storage Application

by Taymour A. Hamdalla, Saleh A. Al-Ghamdi, Shahd Alfadhli, Abdulrhman M. Alsharari, M. Chiesa and Syed Khasim

Catalysts 2024, 14(9), 630; https://doi.org/10.3390/catal14090630 - 18 Sep 2024

Viewed by 849

Abstract

Herein, we report the synthesis of activated biochar from green algae and the effect of its doping on the structural, photocatalytic, and energy storage properties of PEDOT-PSS. The morphology of pure and doped samples was investigated with Fourier Transform Infrared Spectroscopy (FTIR), Atomic [...] Read more.

Herein, we report the synthesis of activated biochar from green algae and the effect of its doping on the structural, photocatalytic, and energy storage properties of PEDOT-PSS. The morphology of pure and doped samples was investigated with Fourier Transform Infrared Spectroscopy (FTIR), Atomic Force Microscopy (AFM), Brunauer–Emmett–Teller (BET) analysis, and thermogravimetric analysis (TGA). AFM results for PEDOT-PSS@6wt.% of BC indicate that the calculated average peak height, particle size, and roughness were 283 nm, 136 nm, and 71 nm, respectively. Adding biochar to PEDOT-PSS significantly improved the thermal stability of PEDOT-PSS up to 550 °C. The novel photocatalyst PEDOT-PSS@6wt.% BC improved photocatalytic performance by approximately 17% in Methylene Blue (MB) dye removal. The electrochemical performance in terms of supercapacitors for the synthesized samples was investigated using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), specific capacitance, stability, and electrochemical impedance spectra (EIS). PEDOT-PSS@6wt.% of BC as a novel electrode material in supercapacitors exhibits an initial specific capacitance of 1300 Fg⁻¹. Moreover, the PEDOT-PSS@6wt.% of BC electrode shows excellent stability up to 1000 cycles of operation. The EIS studies suggest the presence of charge transfer resistance. Considering the economical biosynthesis and multifunctional features, the PEDOT-PSS@6wt.% of BC could potentially be used as a photocatalyst to remove organic dyes and supercapacitors in energy storage applications. Full article

(This article belongs to the Special Issue Advances in Catalysis for Sustainable Energy and Environmental Remediation)

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14 pages, 4623 KiB

Open AccessArticle

Synergic Effects of Ordered Mesoporous Bifunctional Ionic Liquid: A Recyclable Catalyst to Access Chemoselective N-Protected Indoline-2,3-dione Analogous

by Gouthaman Siddan and Viswas Raja Solomon

Catalysts 2024, 14(9), 629; https://doi.org/10.3390/catal14090629 - 17 Sep 2024

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Abstract

SBA-15 and organic ionic liquid were incorporated in a post-grafting technique for generating a bifunctional ionic liquid embedded mesoporous SBA-15. The prepared heterogeneous catalyst was employed for the first time to synthesize N-alkylated indoline-2,3-dione at mild conditions to afford excellent yields in [...] Read more.

SBA-15 and organic ionic liquid were incorporated in a post-grafting technique for generating a bifunctional ionic liquid embedded mesoporous SBA-15. The prepared heterogeneous catalyst was employed for the first time to synthesize N-alkylated indoline-2,3-dione at mild conditions to afford excellent yields in a short reaction time. The synthesized DABCOIL@SBA-15 catalyst was meticulously characterized by various techniques, such as FT-IR, solid-state ¹³C NMR, solid-state ²⁹Si NMR, small-angle X-ray diffraction (XRD), and N₂ adsorption–desorption. Further, the morphological behavior of the catalyst was studied by SEM and TEM. The thermal stability and number of active sites were determined by thermogravimetric analysis (TGA). The Hammett equation was used to analyze the synergetic effect of the catalyst and substituent effects on the N-alkylated products of 5-substituted isatin derivatives, which resulted in a negative slope. This negative slope indicates a positive charge in the transition state. Notably, the DABCOIL@SBA-15 catalyst demonstrated its practicality by being reused for seven cycles with consistently high catalytic activity. Full article

(This article belongs to the Special Issue Mesoporous Nanostructured Materials for Heterogeneous Catalysis)

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15 pages, 3666 KiB

Open AccessArticle

Novel Approach to Organization of Structured Cobalt-Based Fischer–Tropsch Catalyst

by Andrei Gorshkov, Lilia Sineva, Kirill Gryaznov and Vladimir Mordkovich

Catalysts 2024, 14(9), 628; https://doi.org/10.3390/catal14090628 - 17 Sep 2024

Viewed by 587

Abstract

Structured Fischer–Tropsch synthesis catalysts were tested in tubular reactors of industry-standard diameters of 0.5 or 0.75 inches. The structured catalyst bed was manufactured by the obturation of a straight bunch of graphite-based extrudates (D = 1.5 mm, L = 30 mm). A conventional [...] Read more.

Structured Fischer–Tropsch synthesis catalysts were tested in tubular reactors of industry-standard diameters of 0.5 or 0.75 inches. The structured catalyst bed was manufactured by the obturation of a straight bunch of graphite-based extrudates (D = 1.5 mm, L = 30 mm). A conventional loose bed of granulated catalyst (D = 1.5 mm, L = 3 mm) was tested as a reference. In a 1000–3000 h⁻¹ syngas space velocity range, structured and loose catalyst bed testing showed no significant differences in their main catalytic parameters. Nevertheless, their C₅₊ hydrocarbon group composition was quite different, i.e., the alkene fraction rose from 9 to 23%, while n-alkanes dropped from 81 to 64%. This could be a result of secondary reaction intensification in the conventional loose bed due to its zeolite acid site’s higher availability. Further FTS testing of the structured catalysts in 4000–6000 h⁻¹ manifested distinctive limits in C₅₊ productivity for 0.5 and 0.75 inches of 512 kg C₅₊/(m³ reactor·h) and 362 kg C₅₊/(m³ reactor·h), respectively. This may be explained by limitations in structured bed thermal conductivity. It suggests that the arrangement of extrudates in the structured catalyst can significantly affect the reaction heat and mass transfer conditions and affords new opportunities for group composition control by means of catalyst bed organization. Full article

(This article belongs to the Section Catalysis in Organic and Polymer Chemistry)

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28 pages, 7112 KiB

Open AccessReview

Tuning the Electronic Structures of Mo-Based Sulfides/Selenides with Biomass-Derived Carbon for Hydrogen Evolution Reaction and Sodium-Ion Batteries

by Hongying Pan, Kaiyang Zheng, Zihan Chen, Yuexin Wang, Yajun Tan, Jian Wang, Luye Yao, Lixin Wang, Chencheng Sun and Jun Yang

Catalysts 2024, 14(9), 627; https://doi.org/10.3390/catal14090627 - 17 Sep 2024

Viewed by 887

Abstract

A key research focus at present is the exploration and innovation of electrode materials suitable for energy storage and conversion. Molybdenum-based sulfides/selenides (primarily MoS₂ and MoSe₂) have garnered attention in recent years due to their intrinsic two-dimensional structures, which are [...] Read more.

A key research focus at present is the exploration and innovation of electrode materials suitable for energy storage and conversion. Molybdenum-based sulfides/selenides (primarily MoS₂ and MoSe₂) have garnered attention in recent years due to their intrinsic two-dimensional structures, which are conducive to ion/electron transfer or insertion/extraction, making them promising candidates in electrocatalytic hydrogen production and sodium-ion battery applications. However, their inherently poor electronic structures have led most research efforts to concentrate on modifications aimed at enhancing their performance in hydrogen evolution reactions (HERs) and sodium-ion batteries (SIBs). Owing to their remarkable chemical inertness, expansive specific surface areas, and tunable pore architectures, carbon-based materials have garnered significant attention in research. The utilization of biomass as a renewable and environmentally sustainable precursor offers considerable benefits, including abundant availability, ecological compatibility, and cost-effectiveness. Consequently, recent scholarly endeavors have concentrated intensively on the synthesis of valuable carbon materials derived from renewable biomass sources. This review addresses the scientific challenges related to the development of electrode materials for HERs and SIBs in electrochemical energy storage and conversion. It delves into the recent focus on the two-dimensional transition-metal chalcogenides, particularly MoS₂ and MoSe₂, and the difficulties encountered in modulating their electronic structures when applied to HERs and SIBs. The review proposes the use of eco-friendly and widely sourced biomass-derived carbon (BMC) as a supporting matrix combined with MoS₂ and MoSe₂ to regulate their structures and enhance their electrocatalytic activity and sodium storage performance. Additionally, it highlights the existing challenges faced by these BMC/MoS₂ and BMC/MoSe₂ composites and offers insights into future developments. Full article

(This article belongs to the Special Issue Electronic Structures Modulation of Transition Metal Chalcogenides for Energy Storage and Catalysis Applications)

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10 pages, 2750 KiB

Open AccessFeature PaperArticle

Carbon Nanofiber-Encapsulated FeCoNiCuMn Sulfides with Tunable S Doping for Enhanced Oxygen Evolution Reaction

by Yuhan Sun, Chen Shen, Mingran Wang, Yang Cao, Qianwei Wang, Jiayi Rong, Tong He, Duanyang Li and Feng Cao

Catalysts 2024, 14(9), 626; https://doi.org/10.3390/catal14090626 - 17 Sep 2024

Viewed by 686

Abstract

The oxygen evolution reaction (OER) stands out as a key electrochemical process for the conversion of clean energy. However, the practical implementation of OER is frequently impeded by its slow kinetics and the necessity for scarce and expensive noble metal catalysts. High-entropy transition [...] Read more.

The oxygen evolution reaction (OER) stands out as a key electrochemical process for the conversion of clean energy. However, the practical implementation of OER is frequently impeded by its slow kinetics and the necessity for scarce and expensive noble metal catalysts. High-entropy transition metal sulfides (HETMS) stand at the forefront of OER catalysts, renowned for their exceptional catalytic performance and diversity. Herein, we have synthesized a HETMS catalyst, (FeCoNiCuMn₅₀)S₂, encapsulated within carbon nanofibers through a one-step process involving the synergistic application of electrospinning and chemical vapor deposition. By precisely controlling the doping levels of sulfur, we have demonstrated that sulfur incorporation significantly increases the exposed surface area of alloy particles on carbon nanofibers and optimizes the electronic configuration of the alloy elements. These findings reveal that sulfur doping is instrumental in the substantial improvement of the catalyst’s OER performance. Notably, the catalyst showed optimal activity at a sulfur-to-metal atom ratio of 2:1, delivering an overpotential of 254 mV at a current density of 10 mA cm⁻² in 1.0 M KOH solution. Furthermore, the (FeCoNiCuMn₅₀)S₂ catalyst exhibited remarkable electrochemical stability, underscoring its potential as an efficient and robust OER electrocatalyst for sustainable energy applications. Full article

(This article belongs to the Section Catalytic Materials)

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