首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到10条相似文献,搜索用时 203 毫秒
1.
<正>Over the past decade, to meet the ever increased demand on high-performance catalysts with excellent activity, selectivity and stability, the nanocatalysts and catalysis have been rigorously explored, resulting in a noticeable progress in new paradigm of nanoscience and nanotechnology for catalysis. Differing remarkably from conventional bulk catalysts, size shrinkage of active components to nanometer scale gives a rise to significantly increased catalytic activity, owing to the high surface-to-volume ratio of small particles as well as a large  相似文献   

2.
Over the past decade, to meet the ever increased demand on high-performance catalysts with excellent activity, selectivity and stability, the nanocatalysts and catalysis have been rigorously explored, resulting in a noticeable progress in new paradigm of nanoscience and nanotechnology for catalysis. Differing remarkably from conventional bulk catalysts, size shrinkage of active components to nanometer scale gives a rise to significantly increased catalytic activity, owing to the high surface-to-volume ratio of small particles as well as a large fraction of active atoms with dangling bonds exposed surfaces. In addition, other unique properties of nanomaterials such as surface- and strain-driven lattice distortion, variation in electronic state density and oxidation-induced charge redistribution could also benefit the catalytic performance.  相似文献   

3.
Oil-soluble MoS2 nanoparticles with narrow size distribution have been synthesized by a facile composite-surfactants-aided-solvothermal process.The as-prepared nanoparticles can be directly used as hydrogenation nanocatalysts or as precursors to achieve efficient supported nanocatalysts.The surfaces of these nanoparticles are proposed to be encapsulated within a layer of organic modifiers,which are responsible for the enhancement of their solubility in organic solvents.The activated-carbon supported MoS2 nanocatalysts exhibit higher activity than the unsupported ones towards hydrogenation reactions of naphthalene,owing to the synergistic effects between nanoparticles and supports.The advantages of the present nanocatalysts,such as removal of conventional presulfiding requirements and reduction of nanoparticle aggregations,make them become promising applications in related petroleum chemical industry.  相似文献   

4.
MoS_2 has emerged for catalyzing the hydrogen evolution reaction.Various notable strategies have been developed to downsize the MoS_2 particles and expose more active edges.However,the restacking issue,which reduces the exposure degree,has rarely been taken into account.Herein,we report on a facile proton-induced fast hydrothermal approach to produce size-controllable MoS_2 nanocatalysts and demonstrate that along the varying of sheet sizes,there is a trade-off between the intrinsic catalytic activity(mainly determined by the unsaturated sulfur on the sheet edges) and the active edge accessibility(influenced by the assembly structure).The size-optimized catalyst delivers a high performance of a low overpotential of~200 mV at 10 mA/cm2,a Tafel slope of 46.3 mV/dec,and a stable working state,which is comparable to the recent notable works.Our findings will provide a pathway for its large-scale application and enhance the water electrolysis performance.  相似文献   

5.
The carbon nanotubes supported palladium(Pd/CNT)nanocatalysts were modified by cerium oxides/ hydroxides and their catalytic performances for methanol oxidation were evaluated.Electrochemical measurements indicate that the introduction of cerium remarkably improves the catalytic activity of Pd/CNT catalysts towards methanol oxidation.X-Ray photoelectron spectra results reveal an interaction between palladium and cerium oxides.It is also observed that cerium-modified catalysts have excellent poison resistances,which is attributed to the poison-removal ability of cerium oxides/hydroxides.The highly oxidized cerium oxides/hydroxides have a strong ability to inhibit the accumulation of carbonaceous intermediates on the active sites of Pd catalysts.  相似文献   

6.
Hydrogen energy could be a economic and powerful technology for sustainable future. Producing hydrogen fuel by electrochemical water splitting has attracted intense interest. Due to their physical and chemical properties, two-dimensional(2 D) nanomaterials have sparked immense interest in water electrocatalysis for hydrogen production. This review focuses on the emerging nanocatalysts in 2 D nanoarchitectures for electrocatalytic hydrogen production. The fundamentals of HER are firstly depicted,...  相似文献   

7.
Hydrogen energy could be a economic and powerful technology for sustainable future. Producing hydrogen fuel by electrochemical water splitting has attracted intense interest. Due to their physical and chemical properties, two-dimensional(2 D) nanomaterials have sparked immense interest in water electrocatalysis for hydrogen production. This review focuses on the emerging nanocatalysts in 2 D nanoarchitectures for electrocatalytic hydrogen production. The fundamentals of HER are firstly depicted,...  相似文献   

8.
Gold has been regarded as a poor heterogeneous catalyst because it is generally considered a nonreactive metal. But as nanocatalysts,gold and other metals somehow significantly enhance reactivity. It is generally thought chemical bonds of reactants are weakened by adsorption to nanocatalysts thereby allowing reactions to proceed more rapidly,but how this reaction proceeds to completion is not well understood. Here gold nanocatalysts are treated as unsupported nanoparticles (NPs) in a solution of reactant molecules from which extensions are made to gold NPs supported on titanium dioxide. Whether the NPs are supported or unsupported,enhanced catalytic reactivity depends on absorbed thermal kT (k is Boltzmann's constant and T is absolute temperature) energy accumulated from prior collisions of reactant molecules. The accumulated kT energy is treated as electromagnetic thereby allowing frequency up-conversion by quantum electrodynamics (QED) to the confinement frequency of the NP,typically beyond the vacuum ultraviolet (VUV). By this theory,the chemical reaction of reactant molecules having bonds weakened by adsorption is completed by QED induced VUV photolysis.  相似文献   

9.
Oxide nanostructures grown on noble metal surfaces are often highly active in many reactions,in which the oxide/metal interfaces play an important role.In the present work,we studied the surface structures of Fe Ox-on-Pt and Ni Ox-on-Pt catalysts and their activity to CO oxidation reactions using both model catalysts and supported nanocatalysts.Although the active Fe O1x structure is stabilized on the Pt surface in a reductive reaction atmosphere,it is prone to change to an Fe O2x structure in oxidative reaction gases and becomes deactivated.In contrast,a Ni O1x surface structure supported on Pt is stable in both reductive and oxidative CO oxidation atmospheres.Consequently,CO oxidation over the Ni O1x-on-Pt catalyst is further enhanced in the CO oxidation atmosphere with an excess of O2.The present results demonstrate that the stability of the active oxide surface phases depends on the stabilization effect of the substrate surface and is also related to whether the oxide exhibits a variable oxidation state.  相似文献   

10.
<正>In order to increase the involvement of younger researchers in and improve the international impact and visibility of the journal,SCIENCE CHINA Chemistry held a gathering of the inaugural Young Scientists Committee in Beijing on March 15,2014.The committee members were appointed by the journal’s editorial team and represent a select group of 26 young researchers in chemistry and allied fields.Appointment to the committee is two years,during which time the committee members will have representation on the Editorial Board of SCIENCE CHINA Chemistry.Committee members will have the opportunity to work with the Board on a number of editorial duties,such as conducting peer review for the journal and  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号