Modulating the Hydrogenation Mechanism of Electrochemical CO2 Reduction Using Ruthenium Atomic Species on Bismuth

Abstract The conversion of CO 2 into formate through electrochemical methods is emerging as an elegant approach for industrial‐scale CO 2 utilization in the near future. Although Bismuth (Bi)‐based materials have shown promise thank to their excellent selectivity, their limited reactivity remains a challenge. Herein, this study demonstrates a significant enhancement in the CO 2 ‐to‐formate efficiency of Bi by incorporating ruthenium (Ru) atomic species. Ru single atom doped Bi exhibited a nearly twofold higher partial current density compared with pure Bi and Ru clusters doped Bi, while over 95% Faradaic efficiency (FE) is maintained. Through comprehensive investigations using a combined approach of electrochemical techniques, operando spectroscopy, and theoretical calculations, this study elucidates that the presence of Ru single atom promotes H 2 O dissociation and H* migration to Bi sites for CO 2 ‐to‐formate conversion by significantly reducing the energy barrier via a H* spillover path. Besides, it is constructed Ru–Bi bridge sites for efficient CO 2 hydrogenation via a non‐spillover path, which served as the major mechanism for CO 2 ‐to‐formate conversion in Ru single atom doped Bi.