Tuning the electrochemical stability of carbon based single-atom structures via doping: trade-off between electrosorption/leaching behavior†

Abstract

The performance of single-atom catalysts in electrocatalytic processes can be effectively enhanced through the doping of tailored asymmetric coordination environments. However, understanding the electrochemical stability of doped single-atom structures (SAS) under operating conditions remains challenging. In this study, density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations are employed to elucidate the combined effects of proton–electron adsorption and Cu leaching from the Cu–N₄ structure. By considering 6 thermodynamically and kinetically stable heteroatom-doped CuN₃X structures, the relationship between the proton–electron adsorption energy barriers and Cu leaching energy barriers for 96 proton adsorption configurations is explored. A trade-off between these two factors leads to the identification of the CuN₃B structure as the most stable. Surface phase diagrams indicate that B doping effectively suppresses Cu leaching, while S doping exacerbates it. Electronic structure analysis further highlights that B doping enhances the hybridization coincidence of Cu–N orbitals, thereby strengthening the Cu–N bond, reducing proton adsorption on N, and ultimately stabilizing the Cu single-atom structure. Overall, this study investigates the electrochemical stability of Cu SAS and their underlying mechanisms, offering new insights into the electrochemical stability of SAS.