Hefei National Laboratory for Physical Sciences at the Microscale, Collaborative Innovation Center of Chemistry for Energy Materials, School of Chemistry and Materials Science, and CAS Key Laboratory of Materials for Energy Conversion, University of Science and Technology of China, Hefei, Anhui 230026 (P. R. China) http://staff.ustc.edu.cn/∼yjxiong/
Angew Chem Int Ed Engl. 2015 May 4;54(19):5666-71. doi: 10.1002/anie.201500947. Epub 2015 Mar 10.
Pt(100) facets are generally considered less active for the oxygen reduction reaction (ORR). Reported herein is a unique Pt-branched structure, a multicube, whose surface is mostly enclosed by {100} facets but contains high-index facets at the small junction area between the adjacent cubic components. The synthesis is accomplished by a Ni(2+) -mediated facet evolution from high-index {311} to {100} facets on the frameworks of multipods. Despite the high {100} facet coverage, the Pt multicubes exhibit impressive ORR activity in terms of half-wave potential and current density nearly to the level of the most active Pt-based catalysts, while the durability of catalysts is well retained. The facet evolution creates a set of samples with tunable ratios of high-index to low-index facets. The results reveal that the excellent ORR performance of Pt multicubes is a combined result of active sites by high-index facets and low resistance by flat surface. It is anticipated that this work will offer a new approach to facet-controlled synthesis and ORR catalysts design.
Pt(100) 面通常被认为对氧还原反应 (ORR) 的活性较低。本文报道了一种独特的 Pt 分支结构，即多面体，其表面主要由 {100} 面封闭，但在相邻立方组件之间的小连接区域包含高指数面。该合成是通过 Ni(2+) 介导的从多支的高指数 {311} 到 {100} 面的晶面演化来实现的。尽管 {100} 面覆盖率很高，但 Pt 多面体在半波电势和电流密度方面表现出令人印象深刻的 ORR 活性，几乎达到了最活跃的基于 Pt 的催化剂的水平，同时催化剂的耐久性也得到了很好的保留。晶面演化创造了一组具有可调高指数与低指数面比例的样品。结果表明，Pt 多面体优异的 ORR 性能是高指数面的活性位和平面的低电阻的综合结果。预计这项工作将为晶面控制合成和 ORR 催化剂设计提供新的途径。
