Nanomaterials

Research

Jump to: Review

12 pages, 2911 KiB

Open AccessArticle

Porous Si/Fe₂O₃ Dual Network Anode for Lithium–Ion Battery Application

by Yanxu Chen, Yajing Yan, Xiaoli Liu, Yan Zhao, Xiaoyu Wu, Jun Zhou and Zhifeng Wang

Nanomaterials 2020, 10(12), 2331; https://doi.org/10.3390/nano10122331 - 25 Nov 2020

Cited by 14 | Viewed by 3217

Abstract

Benefiting from ultra-high theoretical capacity, silicon (Si) is popular for use in energy storage fields as a Li–ion battery anode material because of its high-performance. However, a serious volume variation happens towards Si anodes in the lithiation/delithiation process, triggering the pulverization of Si [...] Read more.

Benefiting from ultra-high theoretical capacity, silicon (Si) is popular for use in energy storage fields as a Li–ion battery anode material because of its high-performance. However, a serious volume variation happens towards Si anodes in the lithiation/delithiation process, triggering the pulverization of Si and a fast decay in its capacity, which greatly limits its commercial application. In our study, a porous Si/Fe₂O₃ dual network anode was fabricated using the melt-spinning, ball-milling and dealloying method. The anode material shows good electrochemical performance, delivering a reversible capacity of 697.2 mAh g⁻¹ at 200 mA g⁻¹ after 100 cycles. The high Li storage property is ascribed to the rich mesoporous distribution of the dual network structure, which may adapt the volume variation of the material during the lithiation/delithiation process, shorten the Li–ion diffusion distance and improve the electron transport speed. This study offers a new idea for developing natural ferrosilicon ores into the porous Si-based materials and may prompt the development of natural ores in energy storage fields. Full article

(This article belongs to the Special Issue Novel Nanomaterials for Applications in Energy and Catalysis)

► Show Figures

Figure 1

11 pages, 3961 KiB

Open AccessArticle

One-Pot Synthesized Biomass C-Si Nanocomposites as an Anodic Material for High-Performance Sodium-Ion Battery

by Sankar Sekar, Abu Talha Aqueel Ahmed, Deuk Young Kim and Sejoon Lee

Nanomaterials 2020, 10(9), 1728; https://doi.org/10.3390/nano10091728 - 31 Aug 2020

Cited by 21 | Viewed by 3602

Abstract

Aiming at materializing an excellent anodic source material of the high-performance sodium-ion battery (SIB), we fabricated the biomass carbon-silicon (C-Si) nanocomposites by the one-pot synthesis of facile magnesiothermic reduction using brown rice husk ashes. The C-Si nanocomposites displayed an aggregated morphology, where the [...] Read more.

Aiming at materializing an excellent anodic source material of the high-performance sodium-ion battery (SIB), we fabricated the biomass carbon-silicon (C-Si) nanocomposites by the one-pot synthesis of facile magnesiothermic reduction using brown rice husk ashes. The C-Si nanocomposites displayed an aggregated morphology, where the spherical Si nanoparticles (9 nm on average) and the C nanoflakes were encapsulated and decorated with each other. When utilizing the nanocomposites as an SIB anode, a high initial discharge capacity (i.e., 378 mAh/g at 100 mA/g) and a high reversible capacity (i.e., 122 mAh/g at 200 mA/g) were achieved owing to their enhanced electronic and ionic conductivities. Moreover, the SIB device exhibited a high cyclic stability in its Coulombic efficiency (i.e., 98% after 100 charge-discharge cycles at 200 mA/g). These outstanding results depict that the one-pot synthesized biomass C-Si nanocomposites are beneficial for future green energy-storage technology. Full article

(This article belongs to the Special Issue Novel Nanomaterials for Applications in Energy and Catalysis)

► Show Figures

Graphical abstract

13 pages, 4129 KiB

Open AccessFeature PaperArticle

Excellent Oxygen Evolution Reaction of Activated Carbon-Anchored NiO Nanotablets Prepared by Green Routes

by Sankar Sekar, Deuk Young Kim and Sejoon Lee

Nanomaterials 2020, 10(7), 1382; https://doi.org/10.3390/nano10071382 - 15 Jul 2020

Cited by 54 | Viewed by 5454

Abstract

A sustainable and efficient electrocatalyst for the oxygen evolution reaction (OER) is vital to realize green and clean hydrogen production technology. Herein, we synthesized the nanocomposites of activated carbon-anchored nickel oxide (AC-NiO) via fully green routes, and characterized their excellent OER performances. The [...] Read more.

A sustainable and efficient electrocatalyst for the oxygen evolution reaction (OER) is vital to realize green and clean hydrogen production technology. Herein, we synthesized the nanocomposites of activated carbon-anchored nickel oxide (AC-NiO) via fully green routes, and characterized their excellent OER performances. The AC-NiO nanocomposites were prepared by the facile sonication method using sonochemically prepared NiO nanoparticles and biomass-derived AC nanosponges. The nanocomposites exhibited an aggregated structure of the AC-NiO nanotablets with an average size of 40 nm. When using the nanotablets as an OER catalyst in 1 M KOH, the sample displayed superb electrocatalytic performances, i.e., a substantially low value of overpotential (320 mV at 10 mA/cm²), a significantly small Tafel slope (49 mV/dec), and a good OER stability (4% decrease of overpotential after 10 h). These outstanding OER characteristics are considered as attributing to the synergetic effects from both the ample surface area of the electrochemically active NiO nanoparticles and the high electrical conductivity of the AC nanosponges. The results pronounce that the fully ecofriendly synthesized AC-NiO nanotablets can play a splendid role as high-performance electrocatalysts for future green energy technology. Full article

(This article belongs to the Special Issue Novel Nanomaterials for Applications in Energy and Catalysis)

► Show Figures

Graphical abstract

18 pages, 5867 KiB

Open AccessArticle

Surface Study of CuO Nanopetals by Advanced Nanocharacterization Techniques with Enhanced Optical and Catalytic Properties

by Muhammad Arif Khan, Nafarizal Nayan, Shadiullah, Mohd Khairul Ahmad and Chin Fhong Soon

Nanomaterials 2020, 10(7), 1298; https://doi.org/10.3390/nano10071298 - 2 Jul 2020

Cited by 122 | Viewed by 7221

Abstract

In the present work, a facile one-step hydrothermal synthesis of well-defined stabilized CuO nanopetals and its surface study by advanced nanocharacterization techniques for enhanced optical and catalytic properties has been investigated. Characterization by Transmission electron microscopy (TEM) analysis confirmed existence of high crystalline [...] Read more.

In the present work, a facile one-step hydrothermal synthesis of well-defined stabilized CuO nanopetals and its surface study by advanced nanocharacterization techniques for enhanced optical and catalytic properties has been investigated. Characterization by Transmission electron microscopy (TEM) analysis confirmed existence of high crystalline CuO nanopetals with average length and diameter of 1611.96 nm and 650.50 nm, respectively. The nanopetals are monodispersed with a large surface area, controlled morphology, and demonstrate the nanocrystalline nature with a monoclinic structure. The phase purity of the as-synthesized sample was confirmed by Raman spectroscopy and X-ray diffraction (XRD) patterns. A significantly wide absorption up to 800 nm and increased band gap were observed in CuO nanopetals. The valance band (VB) and conduction band (CB) positions at CuO surface are measured to be of +0.7 and −1.03 eV, respectively, using X-ray photoelectron spectroscopy (XPS), which would be very promising for efficient catalytic properties. Furthermore, the obtained CuO nanopetals in the presence of hydrogen peroxide (

H_{2} O_{2})

achieved excellent catalytic activities for degradation of methylene blue (MB) under dark, with degradation rate > 99% after 90 min, which is significantly higher than reported in the literature. The enhanced catalytic activity was referred to the controlled morphology of monodispersed CuO nanopetals, co-operative role of

H_{2} O_{2}

and energy band structure. This work contributes to a new approach for extensive application opportunities in environmental improvement. Full article

(This article belongs to the Special Issue Novel Nanomaterials for Applications in Energy and Catalysis)

► Show Figures

Figure 1

13 pages, 3832 KiB

Open AccessArticle

Study on the Effects of a π Electron Conjugated Structure in Binuclear Metallophthalocyanines Graphene-Based Oxygen Reduction Reaction Catalysts

by Gai Zhang, Bulei Liu, Yufan Zhang, Tiantian Li, Weixing Chen and Weifeng Zhao

Nanomaterials 2020, 10(5), 946; https://doi.org/10.3390/nano10050946 - 15 May 2020

Cited by 7 | Viewed by 2679

Abstract

The high overpotentials for oxygen reduction reaction (ORR) create an extremely negative impact on the energy efficiency of the air-based battery systems. To overcome this problem, binuclear ball-type metallophthalocyanines containing methoxy substituents (M₂Pc₂(EP)₄, M = Fe(II), Co(II) [...] Read more.

The high overpotentials for oxygen reduction reaction (ORR) create an extremely negative impact on the energy efficiency of the air-based battery systems. To overcome this problem, binuclear ball-type metallophthalocyanines containing methoxy substituents (M₂Pc₂(EP)₄, M = Fe(II), Co(II) and Zn(II)) were wrapped with polystyrene sodium sulfonate (PSS) modified graphene oxide (GO), using a facilely “solvothermal π-π assembly” method to prepare M₂Pc₂(EP)₄/PSS-Gr composites. Compared with the commercial Pt/C catalysts, the M₂Pc₂(EP)₄/PSS-Gr composites enhanced the catalytic activity of oxygen reduction reaction. The π electron conjugated structure of the MN₄-type phthalocyanine macrocyclic system strongly influenced the one-step four-electron electrocatalytic process of the M₂Pc₂(EP)₄/PSS-Gr composites. Moreover, the π-π interactions between the M₂Pc₂(EP)₄ and PSS-Gr dramatically enhanced the π electron density in the conjugated structure and oxygen could be reduced more easily. The electrocatalytic activity test was displayed in the order of Fe₂Pc₂(FP)₄/PSS-Gr > Co₂Pc₂(EP)₄/PSS-Gr > Zn₂Pc₂(EP)₄/PSS-Gr. The results indicated that the catalytic performance of M₂Pc₂R_n could be enhanced by the modification of π electron conjugated structure of M₂Pc₂(EP)₄ and carbon materials. Full article

(This article belongs to the Special Issue Novel Nanomaterials for Applications in Energy and Catalysis)

► Show Figures

Graphical abstract

11 pages, 2428 KiB

Open AccessArticle

Dopant-Free Triazatruxene-Based Hole Transporting Materials with Three Different End-Capped Acceptor Units for Perovskite Solar Cells

by Da Rim Kil, Chunyuan Lu, Jung-Min Ji, Chul Hoon Kim and Hwan Kyu Kim

Nanomaterials 2020, 10(5), 936; https://doi.org/10.3390/nano10050936 - 13 May 2020

Cited by 8 | Viewed by 3848

Abstract

A series of dopant-free D-π-A structural hole-transporting materials (HTMs), named as SGT-460, SGT-461, and SGT-462, incorporating a planner-type triazatruxene (TAT) core, thieno[3,2-b]indole (TI) π-bridge and three different acceptors, 3-ethylthiazolidine-2,4-dione (ED), 3-(dicyano methylidene)indan-1-one (DI), and malononitrile (MN), were designed and synthesized for [...] Read more.

A series of dopant-free D-π-A structural hole-transporting materials (HTMs), named as SGT-460, SGT-461, and SGT-462, incorporating a planner-type triazatruxene (TAT) core, thieno[3,2-b]indole (TI) π-bridge and three different acceptors, 3-ethylthiazolidine-2,4-dione (ED), 3-(dicyano methylidene)indan-1-one (DI), and malononitrile (MN), were designed and synthesized for application in perovskite solar cells (PrSCs). The effect of three acceptor units in star-shaped D-π-A structured dopant-free HTMs on the photophysical and electrochemical properties and the photovoltaic performance were investigated compared to the reference HTM of 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (spiro-OMeTAD). Their highest occupied molecular orbital (HOMO) energy levels were positioned for efficient hole extraction from a MAPbCl₃₋_xI_x layer (5.43 eV). The hole mobility values of the HTMs without dopants were determined to be 7.59 × 10⁻⁵ cm² V⁻¹ s⁻¹, 5.13 × 10⁻⁴ cm² V⁻¹ s⁻¹, and 7.61 × 10⁻⁴ cm² V⁻¹ s⁻¹ for SGT-460-, SGT-461-, and SGT-462-based films. The glass transition temperature of all HTMs showed higher than that of the spiro-OMeTAD. As a result, the molecular engineering of a planer donor core, π-bridge, and end-capped acceptor led to good hole mobility, yielding 11.76% efficiency from SGT-462-based PrSCs, and it provides a useful insight into the synthesis of the next-generation of HTMs for PrSC application. Full article

(This article belongs to the Special Issue Novel Nanomaterials for Applications in Energy and Catalysis)

► Show Figures

Graphical abstract

14 pages, 3291 KiB

Open AccessArticle

Pistachio Shell-Derived Carbon Activated with Phosphoric Acid: A More Efficient Procedure to Improve the Performance of Li–S Batteries

by Almudena Benítez, Julián Morales and Álvaro Caballero

Nanomaterials 2020, 10(5), 840; https://doi.org/10.3390/nano10050840 - 27 Apr 2020

Cited by 36 | Viewed by 4875

Abstract

A sustainable and low-cost lithium–sulfur (Li–S) battery was produced by reusing abundant waste from biomass as a raw material. Pistachio shell was the by-product from the agri-food industry chosen to obtain activated carbon with excellent textural properties, which acts as a conductive matrix [...] Read more.

A sustainable and low-cost lithium–sulfur (Li–S) battery was produced by reusing abundant waste from biomass as a raw material. Pistachio shell was the by-product from the agri-food industry chosen to obtain activated carbon with excellent textural properties, which acts as a conductive matrix for sulfur. Pistachio shell-derived carbon activated with phosphoric acid exhibits a high surface area (1345 m²·g⁻¹) and pore volume (0.67 cm³·g⁻¹), together with an interconnected system of micropores and mesopores that is capable of accommodating significant amounts of S and enhancing the charge carrier mobility of the electrochemical reaction. Moreover, preparation of the S composite was carried out by simple wet grinding of the components, eliminating the usual stage of S melting. The cell performance was very satisfactory, both in long-term cycling measurements and in rate capability tests. After the initial cycles required for cell stabilization, it maintained good capacity retention for the 300 cycles measured (the capacity loss was barely 0.85 mAh·g⁻¹ per cycle). In the rate capability test, the capacity released was around 650 mAh·g⁻¹ at 1C, a higher value than that supplied by other activated carbons from nut wastes. Full article

(This article belongs to the Special Issue Novel Nanomaterials for Applications in Energy and Catalysis)

► Show Figures

Graphical abstract

19 pages, 4422 KiB

Open AccessArticle

Effective Platinum-Copper Catalysts for Methanol Oxidation and Oxygen Reduction in Proton-Exchange Membrane Fuel Cell

by Vladislav Menshchikov, Anastasya Alekseenko, Vladimir Guterman, Andrey Nechitailov, Nadezhda Glebova, Aleksandr Tomasov, Olga Spiridonova, Sergey Belenov, Natalia Zelenina and Olga Safronenko

Nanomaterials 2020, 10(4), 742; https://doi.org/10.3390/nano10040742 - 13 Apr 2020

Cited by 39 | Viewed by 3871

Abstract

The behavior of supported alloyed and de-alloyed platinum-copper catalysts, which contained 14–27% wt. of Pt, was studied in the reactions of methanol electrooxidation (MOR) and oxygen electroreduction (ORR) in 0.1 M HClO₄ solutions. Alloyed PtCu_x/C catalysts were prepared by a [...] Read more.

The behavior of supported alloyed and de-alloyed platinum-copper catalysts, which contained 14–27% wt. of Pt, was studied in the reactions of methanol electrooxidation (MOR) and oxygen electroreduction (ORR) in 0.1 M HClO₄ solutions. Alloyed PtCu_x/C catalysts were prepared by a multistage sequential deposition of copper and platinum onto a Vulcan XC72 dispersed carbon support. De-alloyed PtCu_x_−y/C catalysts were prepared by PtCu_x/C materials pretreatment in acid solutions. The effects of the catalysts initial composition and the acid treatment condition on their composition, structure, and catalytic activity in MOR and ORR were studied. Functional characteristics of platinum-copper catalysts were compared with those of commercial Pt/C catalysts when tested, both in an electrochemical cell and in H₂/Air membrane-electrode assembly (MEA). It was shown that the acid pretreatment of platinum-copper catalysts practically does not have negative effect on their catalytic activity, but it reduces the amount of copper passing into the solution during the subsequent electrochemical study. The activity of platinum-copper catalysts in the MOR and the current-voltage characteristics of the H₂/Air proton-exchange membrane fuel cell MEAs measured in the process of their life tests were much higher than those of the Pt/C catalysts. Full article

(This article belongs to the Special Issue Novel Nanomaterials for Applications in Energy and Catalysis)

► Show Figures

Graphical abstract

17 pages, 7739 KiB

Open AccessArticle

Controlled Growth and Bandstructure Properties of One Dimensional Cadmium Sulfide Nanorods for Visible Photocatalytic Hydrogen Evolution Reaction

by Rama Krishna Chava, Namgyu Son, Yang Soo Kim and Misook Kang

Nanomaterials 2020, 10(4), 619; https://doi.org/10.3390/nano10040619 - 27 Mar 2020

Cited by 20 | Viewed by 3917

Abstract

One dimensional (1D) metal sulfide nanostructures are one of the most promising materials for photocatalytic water splitting reactions to produce hydrogen (H₂). However, tuning the nanostructural, optical, electrical and chemical properties of metal sulfides is a challenging task for the fabrication [...] Read more.

One dimensional (1D) metal sulfide nanostructures are one of the most promising materials for photocatalytic water splitting reactions to produce hydrogen (H₂). However, tuning the nanostructural, optical, electrical and chemical properties of metal sulfides is a challenging task for the fabrication of highly efficient photocatalysts. Herein, 1D CdS nanorods (NRs) were synthesized by a facile and low-cost solvothermal method, in which reaction time played a significant role for increasing the length of CdS NRs from 100 nm to several micrometers. It is confirmed that as the length of CdS NR increases, the visible photocatalytic H₂ evolution activity also increases and the CdS NR sample obtained at 18 hr. reaction time exhibited the highest H₂ evolution activity of 206.07 μmol.g⁻¹.h⁻¹. The higher H₂ evolution activity is explained by the improved optical absorption properties, enhanced electronic bandstructure and decreased electron-hole recombination rate. Full article

(This article belongs to the Special Issue Novel Nanomaterials for Applications in Energy and Catalysis)

► Show Figures

Graphical abstract

16 pages, 13743 KiB

Open AccessArticle

Nitrogen-Doped Porous Carbon Derived from Biomass Used as Trifunctional Electrocatalyst toward Oxygen Reduction, Oxygen Evolution and Hydrogen Evolution Reactions

by Chinnusamy Sathiskumar, Shanmugam Ramakrishnan, Mohanraj Vinothkannan, Ae Rhan Kim, Srinivasan Karthikeyan and Dong Jin Yoo

Nanomaterials 2020, 10(1), 76; https://doi.org/10.3390/nano10010076 - 31 Dec 2019

Cited by 99 | Viewed by 7084

Abstract

Tremendous developments in energy storage and conversion technologies urges researchers to develop inexpensive, greatly efficient, durable and metal-free electrocatalysts for tri-functional electrochemical reactions, namely oxygen reduction reactions (ORRs), oxygen evolution reactions (OERs) and hydrogen evolution reactions (HERs). In these regards, this present study [...] Read more.

Tremendous developments in energy storage and conversion technologies urges researchers to develop inexpensive, greatly efficient, durable and metal-free electrocatalysts for tri-functional electrochemical reactions, namely oxygen reduction reactions (ORRs), oxygen evolution reactions (OERs) and hydrogen evolution reactions (HERs). In these regards, this present study focuses upon the synthesis of porous carbon (PC) or N-doped porous carbon (N-PC) acquired from golden shower pods biomass (GSB) via solvent-free synthesis. Raman spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) studies confirmed the doping of nitrogen in N-PC. In addition, morphological analysis via field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) provide evidence of the sheet-like porous structure of N-PC. ORR results from N-PC show the four-electron pathway (average n = 3.6) for ORRs with a Tafel slope of 86 mV dec⁻¹ and a half-wave potential of 0.76 V. For OERs and HERs, N-PC@Ni shows better overpotential values of 314 and 179 mV at 10 mA cm⁻², and its corresponding Tafel slopes are 132 and 98 mV dec⁻¹, respectively. The chronopotentiometry curve of N-PC@Ni reveals better stability toward OER and HER at 50 mA cm⁻² for 8 h. These consequences provide new pathways to fabricate efficient electrocatalysts of metal-free heteroatom-doped porous carbon from bio-waste/biomass for energy application in water splitting and metal air batteries. Full article

(This article belongs to the Special Issue Novel Nanomaterials for Applications in Energy and Catalysis)

► Show Figures

Graphical abstract

13 pages, 4656 KiB

Open AccessArticle

Reductive and Coordinative Effects of Hydrazine in Structural Transformations of Copper Hydroxide Nanoparticles

by Xenia Medvedeva, Aleksandra Vidyakina, Feng Li, Andrey Mereshchenko and Anna Klinkova

Nanomaterials 2019, 9(10), 1445; https://doi.org/10.3390/nano9101445 - 11 Oct 2019

Cited by 12 | Viewed by 4034

Abstract

Shape-specific copper oxide nanostructures have attracted increasing attention due to their widespread applications in energy conversion, sensing, and catalysis. Advancing our understanding of structure, composition, and surface chemistry transformations in shaped copper oxide nanomaterials during changes in copper oxidation state is instrumental from [...] Read more.

Shape-specific copper oxide nanostructures have attracted increasing attention due to their widespread applications in energy conversion, sensing, and catalysis. Advancing our understanding of structure, composition, and surface chemistry transformations in shaped copper oxide nanomaterials during changes in copper oxidation state is instrumental from both applications and preparative nanochemistry standpoints. Here, we report the study of structural and compositional evolution of amorphous copper (II) hydroxide nanoparticles under hydrazine reduction conditions that resulted in the formation of crystalline Cu₂O and composite Cu₂O-N₂H₄ branched particles. The structure of the latter was influenced by the solvent medium. We showed that hydrazine, while being a common reducing agent in nanochemistry, can not only reduce the metal ions but also coordinate to them as a bidentate ligand and thereby integrate within the lattice of a particle. In addition to shape and composition transformation of individual particles, concurrent interparticle attachment and ensemble shape evolution were induced by depleting surface stabilization of individual nanoparticles. Not only does this study provide a facile synthetic method for several copper (I) oxide structures, it also demonstrates the complex behavior of a reducing agent with multidentate coordinating ability in nanoparticle synthesis. Full article

(This article belongs to the Special Issue Novel Nanomaterials for Applications in Energy and Catalysis)

► Show Figures

Graphical abstract

11 pages, 5126 KiB

Open AccessCommunication

A Facile Method for Preparing UiO-66 Encapsulated Ru Catalyst and its Application in Plasma-Assisted CO₂ Methanation

by Weiwei Xu, Mengyue Dong, Lanbo Di and Xiuling Zhang

Nanomaterials 2019, 9(10), 1432; https://doi.org/10.3390/nano9101432 - 10 Oct 2019

Cited by 79 | Viewed by 9519

Abstract

With increasing applications of metal-organic frameworks (MOFs) in the field of gas separation and catalysis, the preparation and performance research of encapsulating metal nanoparticles (NPs) into MOFs (M@MOF) have attracted extensive attention recently. Herein, an Ru@UiO-66 catalyst is prepared by a one-step method. [...] Read more.

With increasing applications of metal-organic frameworks (MOFs) in the field of gas separation and catalysis, the preparation and performance research of encapsulating metal nanoparticles (NPs) into MOFs (M@MOF) have attracted extensive attention recently. Herein, an Ru@UiO-66 catalyst is prepared by a one-step method. Ru NPs are encapsulated in situ in the UiO-66 skeleton structure during the synthesis of UiO-66 metal-organic framework via a solvothermal method, and its catalytic activity for CO₂ methanation with the synergy of cold plasma is studied. The crystallinity and structural integrity of UiO-66 is maintained after encapsulating Ru NPs according to the X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). As illustrated by X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM), and mapping analysis, the Ru species of the hydration ruthenium trichloride precursor are reduced to metallic Ru NPs without additional reducing processes during the synthesis of Ru@UiO-66, and the Ru NPs are uniformly distributed inside the Ru@UiO-66. Thermogravimetric analysis (TGA) and N₂ sorption analysis show that the specific surface area and thermal stability of Ru@UiO-66 decrease slightly compared with that of UiO-66 and was ascribed to the encapsulation of Ru NPs in the UiO-66 skeleton. The results of plasma-assisted catalytic CO₂ methanation indicate that Ru@UiO-66 exhibits excellent catalytic activity. CO₂ conversion and CH₄ selectivity over Ru@UiO-66 reached 72.2% and 95.4% under 13.0 W of discharge power and a 30 mL·min⁻¹ gas flow rate (

V_{H_{2}} : V_{C O_{2}} = 4 : 1

), respectively. Both values are significantly higher than pure UiO-66 with plasma and Ru/Al₂O₃ with plasma. The enhanced performance of Ru@UiO-66 is attributed to its unique framework structure and excellent dispersion of Ru NPs. Full article

(This article belongs to the Special Issue Novel Nanomaterials for Applications in Energy and Catalysis)

► Show Figures

Figure 1

Review

Jump to: Research

24 pages, 6745 KiB

Open AccessReview

Yolk–Shell Nanostructures: Syntheses and Applications for Lithium-Ion Battery Anodes

by Geon Dae Moon

Nanomaterials 2020, 10(4), 675; https://doi.org/10.3390/nano10040675 - 3 Apr 2020

Cited by 25 | Viewed by 5491

Abstract

Yolk–shell nanostructures have attracted tremendous research interest due to their physicochemical properties and unique morphological features stemming from a movable core within a hollow shell. The structural potential for tuning inner space is the focal point of the yolk–shell nanostructures in a way [...] Read more.

Yolk–shell nanostructures have attracted tremendous research interest due to their physicochemical properties and unique morphological features stemming from a movable core within a hollow shell. The structural potential for tuning inner space is the focal point of the yolk–shell nanostructures in a way that they can solve the long-lasted problem such as volume expansion and deterioration of lithium-ion battery electrodes. This review gives a comprehensive overview of the design, synthesis, and battery anode applications of yolk–shell nanostructures. The synthetic strategies for yolk–shell nanostructures consist of two categories: templating and self-templating methods. While the templating approach is straightforward in a way that the inner void is formed by removing the sacrificial layer, the self-templating methods cover various different strategies including galvanic replacement, Kirkendall effect, Ostwald ripening, partial removal of core, core injection, core contraction, and surface-protected etching. The battery anode applications of yolk–shell nanostructures are discussed by dividing into alloying and conversion types with details on the synthetic strategies. A successful design of yolk–shell nanostructures battery anodes achieved the improved reversible capacity compared to their bare morphologies (e.g., no capacity retention in 300 cycles for Si@C yolk–shell vs. capacity fading in 10 cycles for Si@C core–shell). This review ends with a summary and concluding remark yolk–shell nanostructures. Full article

(This article belongs to the Special Issue Novel Nanomaterials for Applications in Energy and Catalysis)

► Show Figures

Figure 1

38 pages, 9323 KiB

Open AccessReview

Synthesis and Electrochemical Energy Storage Applications of Micro/Nanostructured Spherical Materials

by Qinghua Gong, Tingting Gao, Tingting Hu and Guowei Zhou

Nanomaterials 2019, 9(9), 1207; https://doi.org/10.3390/nano9091207 - 27 Aug 2019

Cited by 17 | Viewed by 4952

Abstract

Micro/nanostructured spherical materials have been widely explored for electrochemical energy storage due to their exceptional properties, which have also been summarized based on electrode type and material composition. The increased complexity of spherical structures has increased the feasibility of modulating their properties, thereby [...] Read more.

Micro/nanostructured spherical materials have been widely explored for electrochemical energy storage due to their exceptional properties, which have also been summarized based on electrode type and material composition. The increased complexity of spherical structures has increased the feasibility of modulating their properties, thereby improving their performance compared with simple spherical structures. This paper comprehensively reviews the synthesis and electrochemical energy storage applications of micro/nanostructured spherical materials. After a brief classification, the concepts and syntheses of micro/nanostructured spherical materials are described in detail, which include hollow, core-shelled, yolk-shelled, double-shelled, and multi-shelled spheres. We then introduce strategies classified into hard-, soft-, and self-templating methods for synthesis of these spherical structures, and also include the concepts of synthetic methodologies. Thereafter, we discuss their applications as electrode materials for lithium-ion batteries and supercapacitors, and sulfur hosts for lithium–sulfur batteries. The superiority of multi-shelled hollow micro/nanospheres for electrochemical energy storage applications is particularly summarized. Subsequently, we conclude this review by presenting the challenges, development, highlights, and future directions of the micro/nanostructured spherical materials for electrochemical energy storage. Full article

(This article belongs to the Special Issue Novel Nanomaterials for Applications in Energy and Catalysis)

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Novel Nanomaterials for Applications in Energy and Catalysis

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (14 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI