Li Site, Nagarajan Anantha Venkataraman, Alfonso Dominic R, Sun Mingkang, Kauffman Douglas R, Mpourmpakis Giannis, Jin Rongchao
Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.
National Energy Technology Laboratory (NETL), United States Department of Energy, Pittsburgh, PA, USA.
Angew Chem Int Ed Engl. 2021 Mar 15;60(12):6351-6356. doi: 10.1002/anie.202016129. Epub 2021 Feb 12.
Thiolate-protected gold nanoclusters (NCs) are promising catalytic materials for the electrochemical CO reduction reaction (CO RR). In this work an atomic level modification of a Au NC is made by substituting two surface Au atoms with two Cd atoms, and it enhances the CO RR selectivity to 90-95 % at the applied potential between -0.5 to -0.9 V, which is doubled compared to that of the undoped Au . Additionally, the Cd-doped Au Cd exhibits the highest CO RR activity (2200 mA mg at -1.0 V vs. RHE) among the reported NCs. This synergetic effect between Au and Cd is remarkable. Density-functional theory calculations reveal that the exposure of a sulfur active site upon partial ligand removal provides an energetically feasible CO RR pathway. The thermodynamic energy barrier for CO formation is 0.74 eV lower on Au Cd than on Au . These results reveal that Cd doping can boost the CO RR performance of Au NCs by modifying the surface geometry and electronic structure, which further changes the intermediate binding energy. This work offers insights into the surface doping mechanism of the CO RR and bimetallic synergism.
硫醇盐保护的金纳米团簇（NCs）是用于电化学CO还原反应（CO RR）的有前途的催化材料。在这项工作中，通过用两个镉原子取代两个表面金原子对金纳米团簇进行了原子级修饰，在-0.5至-0.9 V的外加电势下，其将CO RR选择性提高到了90-95%，与未掺杂的金相比提高了一倍。此外，在已报道的纳米团簇中，镉掺杂的Au₂Cd在-1.0 V（相对于可逆氢电极）时表现出最高的CO RR活性（2200 mA mg）。金和镉之间的这种协同效应非常显著。密度泛函理论计算表明，部分配体去除后硫活性位点的暴露提供了一条能量上可行的CO RR途径。在Au₂Cd上形成CO的热力学能垒比在Au上低0.74 eV。这些结果表明，镉掺杂可以通过改变表面几何结构和电子结构来提高金纳米团簇的CO RR性能，进而改变中间体的结合能。这项工作为CO RR的表面掺杂机制和双金属协同作用提供了见解。
