The Experts below are selected from a list of 4734 Experts worldwide ranked by ideXlab platform
Xiong Wen David Lou - One of the best experts on this subject based on the ideXlab platform.
-
complex Hollow Nanostructures synthesis and energy related applications
Advanced Materials, 2017Co-Authors: Xiong Wen David LouAbstract:Hollow Nanostructures offer promising potential for advanced energy storage and conversion applications. In the past decade, considerable research efforts have been devoted to the design and synthesis of Hollow Nanostructures with high complexity by manipulating their geometric morphology, chemical composition, and building block and interior architecture to boost their electrochemical performance, fulfilling the increasing global demand for renewable and sustainable energy sources. In this Review, we present a comprehensive overview of the synthesis and energy-related applications of complex Hollow Nanostructures. After a brief classification, the design and synthesis of complex Hollow Nanostructures are described in detail, which include hierarchical Hollow spheres, hierarchical tubular structures, Hollow polyhedra, and multi-shelled Hollow structures, as well as their hybrids with nanocarbon materials. Thereafter, we discuss their niche applications as electrode materials for lithium-ion batteries and hybrid supercapacitors, sulfur hosts for lithium-sulfur batteries, and electrocatalysts for oxygen- and hydrogen-involving energy conversion reactions. The potential superiorities of complex Hollow Nanostructures for these applications are particularly highlighted. Finally, we conclude this Review with urgent challenges and further research directions of complex Hollow Nanostructures for energy-related applications.
-
carbon incorporated nickel cobalt mixed metal phosphide nanoboxes with enhanced electrocatalytic activity for oxygen evolution
Angewandte Chemie, 2017Co-Authors: Xiong Wen David LouAbstract:Hollow Nanostructures have attracted increasing research interest in electrochemical energy storage and conversion owing to their unique structural features. However, the synthesis of Hollow nanostructured metal phosphides, especially nonspherical Hollow Nanostructures, is rarely reported. Herein, we develop a metal-organic framework (MOF)-based strategy to synthesize carbon incorporated Ni-Co mixed metal phosphide nanoboxes (denoted as NiCoP/C). The oxygen evolution reaction (OER) is selected as a demonstration to investigate the electrochemical performance of the NiCoP/C nanoboxes. For comparison, Ni-Co layered double hydroxide (Ni-Co LDH) and Ni-Co mixed metal phosphide (denoted as NiCoP) nanoboxes have also been synthesized. Benefiting from their structural and compositional merits, the as-synthesized NiCoP/C nanoboxes exhibit excellent electrocatalytic activity and long-term stability for OER.
-
Hollow Nanostructures of molybdenum sulfides for electrochemical energy storage and conversion
Small Methods, 2017Co-Authors: Xiong Wen David LouAbstract:Hollow Nanostructures of molybdenum sulfides (MoSx, x = 2 or 3) hold great promise as electrode materials for various energy-related systems owing to their attractive electrochemical properties. Recent advances in the synthesis of Hollow MoSx Nanostructures with tailored morphology and composition are introduced, along with their applications in electrochemical energy storage and conversion, including lithium-ion batteries and the electrocatalytic hydrogen-evolution reaction. The importance of structural and compositional engineering on the electrochemical performance of Hollow MoSx Nanostructures is highlighted. Specifically, bare Hollow MoSx structures, including Hollow spheres and Hollow polyhedral Nanostructures, Hollow MoSx–carbon composite structures, and Hollow transition-metal-incorporated MoSx structures are discussed. Finally, a perspective is provided on current challenges and future research directions in this area.
-
double shelled nanocages with cobalt hydroxide inner shell and layered double hydroxides outer shell as high efficiency polysulfide mediator for lithium sulfur batteries
Angewandte Chemie, 2016Co-Authors: Jintao Zhang, Xiong Wen David LouAbstract:Lithium–sulfur (Li-S) batteries have been considered as a promising candidate for next-generation electrochemical energy-storage technologies because of their overwhelming advantages in energy density. Suppression of the polysulfide dissolution while maintaining a high sulfur utilization is the main challenge for Li–S batteries. Here, we have designed and synthesized double-shelled nanocages with two shells of cobalt hydroxide and layered double hydroxides (CH@LDH) as a conceptually new sulfur host for Li–S batteries. Specifically, the Hollow CH@LDH polyhedra with complex shell structures not only maximize the advantages of Hollow Nanostructures for encapsulating a high content of sulfur (75 wt %), but also provide sufficient self-functionalized surfaces for chemically bonding with polysulfides to suppress their outward dissolution. When evaluated as cathode material for Li–S batteries, the CH@LDH/S composite shows a significantly improved electrochemical performance.
-
metal sulfide Hollow Nanostructures for electrochemical energy storage
Advanced Energy Materials, 2016Co-Authors: Xiong Wen David LouAbstract:Metal sulfide Hollow Nanostructures (MSHNs) have received intensive attention as electrode materials for electrical energy storage (EES) systems due to their unique structural features and rich chemistry. Here, we summarize recent research progress in the rational design and synthesis of various metal sulfide Hollow micro-/Nanostructures with controlled shape, composition and structural complexity, and their applications to lithium ion batteries (LIBs) and hybrid supercapacitors (HSCs). The current understanding of Hollow structure control, including single-shelled, yolk-shelled, multi-shelled MSHNs, and their hybrid micro-/Nanostructures with carbon (amorphous carbon nanocoating, graphene and Hollow carbon), is focused on. The importance of proper structural and compositional control on the enhanced electrochemical properties of MSHNs is emphasized. A relationship between structural and compositional engineering with improved electrochemical activity of MSHNs is sought, in order to shed some light on future electrode design trends for next-generation EES technologies.
Zhiyu Wang - One of the best experts on this subject based on the ideXlab platform.
-
a top down strategy toward 3d carbon nanosheet frameworks decorated with Hollow Nanostructures for superior lithium storage
Advanced Functional Materials, 2016Co-Authors: Yanfeng Dong, Zhiyu Wang, Mingliang Yu, Xuzhen Wang, Zongbin ZhaoAbstract:Graphene has shown great potential in vast fields due to the unique structure and properties, but its practical application is still hindered by high cost and scarcity in supply. The development of low-cost substitute of graphene is thus highly desired to meet the practical demand of upcoming applications where extremely physical properties are not absolutely critical. In this work, a top-down strategy for general synthesis of 3D carbon nanosheet frameworks decorated with metal nanoparticles by a metal nitrate-assisted polymer-blowing process is reported. Such architecture provides a promising structural platform for the fabrication of carbon nanosheet frameworks functionalized with metal oxide or carbon Hollow Nanostructures through subsequent chemical conversion. The unique structures impart intimate structural interconnectivities, highly opened freeway for ionic diffusion, large accessible surface area, as well as high structural stability, opening up a wide horizon for electrochemical applications, for example, high-energy, long-life lithium-ion batteries and lithium–sulfur batteries highlighted in this work.
-
metal organic framework engaged formation of co nanoparticle embedded carbon co9s8 double shelled nanocages for efficient oxygen reduction
Energy and Environmental Science, 2016Co-Authors: Han Hu, Mengzhou Yu, Zhiyu WangAbstract:Hollow Nanostructures with a complex interior and superb structural tenability offer great advantages for constructing advanced catalysts. Herein, we report the designed synthesis of novel Co nanoparticle-embedded carbon@Co9S8 double-shelled nanocages (Co-C@Co9S8 DSNCs) by a metal–organic-framework-engaged strategy. Uniform zeolitic imidazolate framework (ZIF-67)@amorphous CoS yolk–shelled structures are first fabricated and then converted to Co-C@Co9S8 DSNCs by thermal annealing in N2 flow. The Co-C nanocages inside Co9S8 shells function as the active centers for the oxygen reduction reaction (ORR). The Co9S8 shells prevent the Co-C active centers from aggregation while acting as nanoreactors. As a result, the Co-C@Co9S8 DSNCs exhibit excellent performance for the ORR in terms of low over-potential, high current density, excellent stability and methanol tolerance capability.
-
one step synthesis of sno2 and tio2 Hollow Nanostructures with various shapes and their enhanced lithium storage properties
Chemistry: A European Journal, 2012Co-Authors: Zhiyu Wang, Zi Chen Wang, Srinivasan Madhavi, Xiong Wen David LouAbstract:A versatile one-step method for the general synthesis of metal oxide Hollow Nanostructures is demonstrated. This method involves the controlled deposition of metal oxides on shaped α-Fe(2)O(3) crystals which are simultaneously dissolved. A variety of uniform SnO(2) Hollow Nanostructures, such as nanococoons, nanoboxes, Hollow nanorings, and nanospheres, can be readily generated. The method is also applicable to the synthesis of shaped TiO(2) Hollow Nanostructures. As a demonstration of the potential applications of these Hollow Nanostructures, the lithium storage capability of SnO(2) Hollow structures is investigated. The results show that such derived SnO(2) Hollow structures exhibit stable capacity retention of 600-700 mA h g(-1) for 50 cycles at a 0.2 C rate and good rate capability at 0.5-1 C, perhaps benefiting from the unique structural characteristics.
-
metal oxide Hollow Nanostructures for lithium ion batteries
Advanced Materials, 2012Co-Authors: Zhiyu Wang, Liang Zhou, Xiong Wen David LouAbstract:Metal oxide Hollow structures have received great attention because of their many promising applications in a wide range of fields. As electrode materials for lithium-ion batteries (LIBs), metal oxide Hollow structures provide high specific capacity, superior rate capability, and improved cycling performance. In this Research News, we summarize the recent research activities in the synthesis of metal oxide Hollow Nanostructures with controlled shape, size, composition, and structural complexity, as well as their applications in LIBs. By focusing on Hollow structures of some binary metal oxides (such as SnO2, TiO2, Fe2O3, Co3O4) and complex metal oxides, we seek to provide some rational understanding on the effect of nanostructure engineering on the electrochemical performance of the active materials. It is thus anticipated that this article will shed some light on the development of advanced electrode materials for next-generation LIBs.
Xun Wang - One of the best experts on this subject based on the ideXlab platform.
-
well defined metal organic framework Hollow Nanostructures for catalytic reactions involving gases
Advanced Materials, 2015Co-Authors: Zhicheng Zhang, Xun WangAbstract:The miniaturization of metal-organic-framework (MOF) crystals to the nanoscale brings enhanced or novel properties and fulfils specific application needs. The focus here is on a kind of nanoMOF with special configurations and outstanding properties - the Hollow structure. Firstly recent advances on the synthesis of MOF Hollow Nanostructures are introduced. Then, a novel approach based on a heterometallic system is highlighted, by which the facile synthesis of well-defined Hollow MOF structures with high complexity is achieved. Moreover, MOF Hollow Nanostructures are emphasized as hosts/shell materials to incorporate functional catalysts that show dramatically enhanced performances in gas-involved reactions due to their inherent gas-absorption/storage properties.
-
magnesium silicate Hollow Nanostructures as highly efficient absorbents for toxic metal ions
Journal of Physical Chemistry C, 2009Co-Authors: Yuan Zhuang, Guolei Xiang, Yan Yang, Xun WangAbstract:A general one-step route has been developed for the selective synthesis of magnesium silicate Hollow spheres, core−shell spheres, and nanotubes. The formation mechanism was studied. The concentration of NaOH played an important role in the synthesis of Hollow and core−shell spheres, while the addition of glycol played a critical role in the synthesis of silicate nanotubes. These Nanostructures usually have BET surface areas of 200−400 m2/g. Further investigation of their ion exchange performance shows that they are indeed perfect candidates as absorbents for heavy metal ions including Pb2+, Cr3+, Cd2+, etc.
-
magnesium silicate Hollow Nanostructures as highly efficient absorbents for toxic metal ions
Journal of Physical Chemistry C, 2009Co-Authors: Yuan Zhuang, Guolei Xiang, Yan Yang, Xun WangAbstract:A general one-step route has been developed for the selective synthesis of magnesium silicate Hollow spheres, core−shell spheres, and nanotubes. The formation mechanism was studied. The concentration of NaOH played an important role in the synthesis of Hollow and core−shell spheres, while the addition of glycol played a critical role in the synthesis of silicate nanotubes. These Nanostructures usually have BET surface areas of 200−400 m2/g. Further investigation of their ion exchange performance shows that they are indeed perfect candidates as absorbents for heavy metal ions including Pb2+, Cr3+, Cd2+, etc.
Yadong Yin - One of the best experts on this subject based on the ideXlab platform.
-
self templating approaches to Hollow Nanostructures
Advanced Materials, 2019Co-Authors: Ji Feng, Yadong YinAbstract:This current research progress on the fabrication of Hollow Nanostructures by using self-templating methods is reviewed. After a brief introduction to the unique properties and applications of Hollow Nanostructures and the three general fabrication routes, the discussions are focused on the five main self-templating strategies, including galvanic replacement, the Kirkendall effect, Ostwald ripening, dissolution-regrowth, and the surface-protected Hollowing process. Some newly developed synthetic routes are selected and discussed in detail. In conclusion, a summary and the perspectives on the directions that might lead the future development of this exciting field are presented.
-
tailored synthesis of mesoporous tio2 Hollow Nanostructures for catalytic applications
Energy and Environmental Science, 2013Co-Authors: Ji Bong Joo, Michael Dahl, Francisco Zaera, Yadong YinAbstract:Nanostructured TiO2 has attracted significant attention due to its advantageous properties for practical catalytic applications. TiO2 Hollow Nanostructures consisting of nanoscale porous shells are highly desirable because they possess high active surface area, reduced diffusion resistance, and improved accessibility, which provide many new opportunities to the design of highly active nanostructured catalysts. Although much has been explored, tailored synthesis of TiO2-based Hollow Nanostructures towards practical catalytic applications has been very limited. In this article, we first introduce the general synthetic strategies for preparing TiO2 Hollow Nanostructures, and then focus our discussion on the novel synthetic strategies developed in our group with emphasis on controlling the crystallinity as well as physical characteristics of TiO2 Hollow Nanostructures. We further discuss several catalytic applications of TiO2-based Hollow shells and metal@TiO2 yolk–shell Nanostructures for photocatalytic dye degradation, H2 production and gas-phase CO oxidation. Finally, we conclude with our personal perspective on the future research efforts for addressing several remaining challenges in the design of TiO2-based catalysts.
-
mesoporous anatase titania Hollow Nanostructures though silica protected calcination
Advanced Functional Materials, 2012Co-Authors: Ji Bong Joo, Qiao Zhang, Ilkeun Lee, Michael Dahl, Francisco Zaera, Yadong YinAbstract:The crystallization of nanometer-scale materials during high-temperature calcination can be controlled by a thin layer of surface coating. Here, a novel silica-protected calcination process for preparing mesoporous Hollow TiO2 Nanostructures with a high surface area and a controllable crystallinity is presented. This method involves the preparation of uniform silica colloidal templates, sequential deposition of TiO2 and then SiO2 layers through sol–gel processes, calcination to transform amorphous TiO2 to crystalline anatase, and finally etching of the inner and outer silica to produce mesoporous anatase TiO2 shells. The silica-protected calcination step allows crystallization of the amorphous TiO2 layer into anatase nanocrystals, while simultaneously limiting the growth of anatase grains to within several nanometers, eventually producing mesoporous anatase shells with a high surface area (∼311 m2 g−1) and good water dispersibility upon chemical etching of the silica. When used as photocatalysts for the degradation of Rhodamine B under UV irradiation, the as-synthesized mesoporous anatase shells show significantly enhanced photocatalytic activity with greater enhancement for samples calcined at higher temperatures thanks to their improved crystallinity.
-
self templated synthesis of Hollow Nanostructures
Nano Today, 2009Co-Authors: Qiao Zhang, Wenshou Wang, James Goebl, Yadong YinAbstract:Summary In this article we review the current research activities on the fabrication of inorganic Hollow Nanostructures by using self-templating methods. We start with a brief introduction to the traditional template-based methods, including those using hard and soft templates. The concepts and applications of four types of newly developed self-templating approaches are then discussed in detail, including those involving the “surface-protected etching” strategy, Ostwald ripening, the Kirkendall effect, and the galvanic replacement. We finally conclude with a summary and our personal perspectives on the directions in which future work on this field might be focused.
-
formation of Hollow nanocrystals through the nanoscale kirkendall effect
Science, 2004Co-Authors: Yadong Yin, Can K Erdonmez, Steven M Hughes, Robert M Rioux, Gabor A Somorjai, Paul A AlivisatosAbstract:Hollow nanocrystals can be synthesized through a mechanism analogous to the Kirkendall Effect, in which pores form because of the difference in diffusion rates between two components in a diffusion couple. Starting with cobalt nanocrystals, we show that their reaction in solution with oxygen and either sulfur or selenium leads to the formation of Hollow nanocrystals of the resulting oxide and chalcogenides. This process provides a general route to the synthesis of Hollow Nanostructures of a large number of compounds. A simple extension of the process yielded platinum–cobalt oxide yolk-shell Nanostructures, which may serve as nanoscale reactors in catalytic applications.
Amreesh Chandra - One of the best experts on this subject based on the ideXlab platform.
-
cerium doped copper ii oxide Hollow Nanostructures as efficient and tunable sensors for volatile organic compounds
ACS omega, 2018Co-Authors: Inderjeet Singh, Sayan Dey, Sumita Santra, Katharina Landfester, Rafael Munozespi, Amreesh ChandraAbstract:Tuning sensing capabilities of simple to complex oxides for achieving enhanced sensitivity and selectivity toward the detection of toxic volatile organic compounds (VOCs) is extremely important and remains a challenge. In the present work, we report the synthesis of pristine and Ce-doped CuO Hollow Nanostructures, which have much higher VOC sensing and response characteristics than their solid analogues. Undoped CuO Hollow Nanostructures exhibit high response for sensing of acetone as compared to commercial CuO nanoparticles. As a result of doping with cerium, the material starts showing selectivity. CuO Hollow structures doped with 5 at. % of Ce return highest response toward methanol sensing, whereas increasing the Ce doping concentration to 10%, the material shows high response for both—acetone and methanol. The observed tunability in selectivity is directly linked to the varying concentration of the oxygen defects on the surface of the Nanostructures. The work also shows that the use of Hollow nanostr...
-
Hollow Nanostructures of metal oxides as next generation electrode materials for supercapacitors
Scientific Reports, 2018Co-Authors: Vikas Sharma, Inderjeet Singh, Amreesh ChandraAbstract:Hollow Nanostructures of copper oxides help to stabilize appreciably higher electrochemical characteristics than their solid counter parts of various morphologies. The specific capacitance values, calculated using cyclic voltammetry (CV) and charge-discharge (CD) studies, are found to be much higher than the values reported in literature for copper oxide particles showing intriguing morphologies or even composites with trendy systems like CNTs, rGO, graphene, etc. The proposed cost-effective synthesis route makes these materials industrially viable for application in alternative energy storage devices. The improved electrochemical response can be attributed to effective access to the higher number of redox sites that become available on the surface, as well as in the cavity of the Hollow particles. The ion transport channels also facilitate efficient de-intercalation, which results in the enhancement of cyclability and Coulombic efficiency. The charge storage mechanism in copper oxide structures is also proposed in the paper.
-
a new approach for crystallization of copper ii oxide Hollow Nanostructures with superior catalytic and magnetic response
Nanoscale, 2015Co-Authors: Inderjeet Singh, Katharina Landfester, Rafael Munozespi, Amreesh ChandraAbstract:We report the synthesis of copper(II) oxide Hollow Nanostructures at ambient pressure and close to room temperature by applying the soft templating effect provided by the confinement of droplets in miniemulsion systems. Particle growth can be explained by considering a mechanism that involves both diffusion and reaction control. The catalytic reduction of p-nitrophenol in aqueous media is used as a model reaction to prove the catalytic activity of the materials: the synthesized Hollow structures show nearly 100 times higher rate constants than solid CuO microspheres. The kinetic behavior and the order of the reduction reaction change due to the increase of the surface area of the Hollow structures. The synthesis also leads to modification of physical properties such as magnetism.