Boosting the Electrocatalytic Performance of CoPt Alloy with Enhanced Electron Transfer via Atomically Dispersed Cobalt Sites.

Abstract

Designing electrocatalysts with strong electronic metal-support interaction can effectively regulate the electronic properties of metal active centers, therefore maximizing the catalytic performance. As a proof of concept, heteroatoms doped carbon with CoPt alloy and isolated Co single atoms (CoPtCoSA@NSC) are synthesized using CoPt bimetallic metal-organic framework as the precursor in this work. The existence of CoSA on the carbon substrate leads to more electron transfer between CoPt and the support, and appropriate upward shift of the d band center of the catalysts, which can effectively reduce the reaction barrier of rate determine step and boost the catalytic performance of CoPt alloy. The enhanced catalytic activity and stability of CoPtCoSA@NSC are demonstrated experimentally. Remarkably, the overpotential for hydrogen evolution reaction is only 23mV at 10mAcm-2 and the half-wave potential for oxygen reduction reaction is 0.90V, both exceeding the commercial Pt/C benchmark. In addition, CoPtCoSA@NSC also exhibits great potential as a cathode electrocatalyst for Zn-air battery, in terms of large open circuit potential of 1.53V, high power density of 184mWcm-2 , as well as superior cycling stability. This work provides a novel strategy for regulating the electronic structure and catalytic performance of alloy based electrocatalysts.