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贵金属纳米晶的催化性质与其结构密切相关.比表面积越大、配位不饱和的边角原子密度越高,贵金属纳米晶在催化反应过程中表现出的性能往往越优异.相比于常见的具有完整几何形貌的贵金属纳米晶,具有多重分级结构特征的超支化贵金属纳米晶拥有更大的比表面积以及更丰富的配位不饱和的活性位点,因此被认为是一种潜在的性能优异的催化剂.但这种具有多重分级结构特征的超支化贵金属纳米晶无论是在生长机理研究还是可控制备上都还存在巨大的挑战.本文通过简单的湿化学法成功制备出一种具有多重分级结构特征的超支化Rh纳米薄片.该产物由三角形纳米片在扩散限制条件下分级生长形成,整体呈现三次对称性的单晶特征.研究表明,该纳米结构不仅具有出色的结构稳定性,而且其生长级数可通过反应溶剂比例的简单调节进行调控,从而实现Rh纳米薄片比表面积和位于边/角活性位点的原子比例的调控.由于拥有更大的比表面积以及更为丰富的配位不饱和的活性位点,这种具有多重分级结构的超支化Rh纳米薄片在乙醇电催化氧化和苯乙烯催化加氢催化反应中展现出了比目前主流商业催化剂Rh黑更为优异的催化活性.
The catalytic properties of the noble metal nanocrystals are closely related to their structure. The larger the specific surface area, the higher the density of the atoms with the coordinately unsaturated corners, and the more noble metal nanocrystals tend to exhibit better performance during the catalytic reaction.Compared with the common The complete geometry of the noble metal nanocrystals, multi-scale hierarchical structure of the characteristics of hyperbranched precious metal nanocrystals have a larger specific surface area and more abundant sites of coordination and unsaturation, it is considered to be a potential excellent performance However, this kind of multi-hierarchical structure of the characteristics of the super-branched precious metal nanocrystals in both the growth mechanism of research and controllable preparation are still a huge challenge.In this paper, a simple wet chemical method successfully prepared with a multi-level structure Characterized by the hierarchical growth of triangular nanosheets under diffusion-limited conditions and the overall appearance of three-dimensional symmetry of the single crystal.The results show that the nanostructures not only have excellent structural stability, but also its growth The number of stages can be adjusted by simple adjustment of the reaction solvent ratio to achieve Rh nanoflakes Surface area and the proportion of atoms located at the edge / corner active sites.Because of the larger specific surface area and the more abundant sites of coordination and unsaturation, the hyperbranched Rh nanoflakes with multiple hierarchical structures were characterized in ethanol Electrocatalytic oxidation and styrene catalytic hydrogenation catalytic reaction showed more than the current mainstream commercial catalyst Rh black more excellent catalytic activity.