Revealing the Doping Effect on the Enhanced Electrocatalytic CO2 Reduction in Atomically Precise Au25 Nanoclusters

Au25(SR)18 and its alloy clusters hold great potential in electrocatalysis, so exploring their structure-property relationship is essential. Herein, we combined theoretical simulations and electrochemical experiments to reveal the doping effect on the electrocatalytic carbon dioxide reduction reaction (CO2RR) activity of the prototype Au25(SR)18 cluster. The constrained ab initio molecular dynamics (AIMD) simulations revealed that Pd doping elevates the barrier of thiolate (SR) ligand removal, while Cd doping slightly decreases the SR removal barrier and facilitates the ligand etching process. Further examination of the four CO2RR elementary steps showed that Pd or Cd doping would decrease the rate-determining barrier in CO formation and enhance the CO2RR activity, which follows the order of CdAu24 > PdAu24 > Au25. The doping-induced upshift in the d-band center of the reactive Au sites is responsible for boosting the electrocatalytic performance. The electrochemical measurements have validated our computational results, which demonstrated that CdAu24 achieves a maximum CO Faradaic efficiency of 97% with superior intrinsic activity, faster reaction kinetics, and excellent long-term catalytic stability. Overall, this study provides important atomic insights into the doping effect on the reaction kinetics of metal nanoclusters.