Qian Hehe, Wu Jianzhou, Guo Yongsheng, Fang Wenjun
Department of Chemistry, Zhejiang University, Hangzhou 310058, China.
Nanomaterials (Basel). 2021 Jan 29;11(2):340. doi: 10.3390/nano11020340.
The functions of heterogeneous metallic nanocrystals (HMNCs) can be undoubtedly tuned by controlling their morphologies and compositions. As a less-studied kind of HMNCs, corner-satellite multi-metallic nanocrystals (CSMNCs) have great research value in structure-related electrocatalytic performance. In this work, PdAgPt corner-satellite nanocrystals with well-controlled morphologies and compositions have been developed by temperature regulation of a seed-mediated growth process. Through the seed-mediated growth, the morphology of PdAgPt products evolves from Pd@Ag cubes to PdAgPt corner-satellite cubes, and eventually to truncated hollow octahedra, as a result of the expansion of {111} facets in AgPt satellites. The growth of AgPt satellites exclusively on the corners of central cubes is realized with the joint help of Ag shell and moderate bromide, and hollow structures form only at higher reaction temperatures on account of galvanic displacement promoted by the Pd core. In view of the different performances of Pd and Pt toward formic acid oxidation (FAO), this structure-sensitive reaction is chosen to measure electrocatalytic properties of PdAgPt HMNCs. It is proven that PdAgPt CSMNCs display greatly improved activity toward FAO in direct oxidation pathway. In addition, with the help of AgPt heterogeneous shells, all PdAgPt HMNCs exhibit better durability than Pd cubes and commercial Pt.
通过控制异质金属纳米晶体（HMNCs）的形貌和组成，其功能无疑可以得到调控。作为一种研究较少的HMNCs，角卫星型多金属纳米晶体（CSMNCs）在与结构相关的电催化性能方面具有很大的研究价值。在这项工作中，通过种子介导生长过程的温度调控，制备出了形貌和组成可控的PdAgPt角卫星纳米晶体。通过种子介导生长，由于AgPt卫星中{111}面的扩展，PdAgPt产物的形貌从Pd@Ag立方体演变为PdAgPt角卫星立方体，最终变为截顶空心八面体。在Ag壳层和适量溴化物的共同作用下，实现了AgPt卫星仅在中心立方体的角上生长，并且由于Pd核促进的电偶置换作用，空心结构仅在较高反应温度下形成。鉴于Pd和Pt对甲酸氧化（FAO）的性能不同，选择这种结构敏感反应来测量PdAgPt HMNCs的电催化性能。结果表明，PdAgPt CSMNCs在直接氧化途径中对FAO表现出大大提高的活性。此外，在AgPt异质壳层的帮助下，所有PdAgPt HMNCs都表现出比Pd立方体和商业Pt更好的耐久性。
