Probing the atomic-scale dynamics of Cu-N-C catalysts during CO2 electroreduction via constant-potential ab-initio molecular dynamics

초록

Atomically dispersed Cu single atoms anchored on N-doped graphene (Cu-N-C) have demonstrated significant potential for the electrochemical CO2 reduction reaction (CO2RR) toward multi‑carbon (C2+) products. However, their catalytic performance is influenced by electrochemically induced structural transformations, particularly the structural evolution of atomically dispersed Cu into metallic Cu nanoparticles. Although this structural transformation has been widely observed experimentally, its atomistic mechanism remains unclear and requires further clarification. In this work, we employed constant-potential ab initio molecular dynamics simulations (AIMD) to investigate the dynamic structural evolution of Cu-N-C under realistic CO2RR conditions. Our simulations reveal that CuN4 sites remain stable under pristine states and during the hydrogen evolution reaction (HER) but undergo dissolution in the presence of N-H terminations and key CO2RR intermediates. Among these, CO* is identified as the most critical species driving Cu dissolution. The dissolved Cu ions subsequently aggregate and redeposit on CuN4 site, forming Cu nanoparticles (NP) on Cu-N-C. Furthermore, we find that carbon defects markedly strengthen Cu-N bonding, thereby suppressing Cu dissolution even under reactive conditions involving the over‑hydrogenation of the coordinating nitrogen atoms. These findings provide mechanistic insights and a unified framework into the electrochemical reconstruction of Cu-N-C catalysts, highlighting the crucial roles of local coordination, specific intermediates, and water molecules in driving structural transformations. © 2026