Leveraging Atomic-Scale Synergy for Selective CO₂ Electrocatalysis to CO over CuNi Dual-Atom Catalysts

Revealing the synergistic catalytic mechanism involving multiple active centers is crucial for understanding multiphase catalysis. However, the complex structures of catalysts and interfacial environments pose a challenge in thoroughly exploring the experimental evidence. This study reports the utilization of a CuNi dual-atom catalyst (Cu/Ni–NC) for the electrochemical reduction of CO2. It demonstrates a high Faradaic efficiency of CO exceeding 99%, remarkable reaction activity with a partial current density surpassing –300 mA cm–2, and prolonged stability for more than 5 days at a current density of –200 mA·cm–2. Operando characterization techniques and density functional theory calculations reveal that Ni atoms function as active sites for the activation and hydrogenation of CO2, while Cu atoms serve as active sites for the dissociation of H2O, supplying protons for the subsequent hydrogenation process. Moreover, the electronic interactions between Ni and Cu atoms facilitate the formation of *COOH and the dissociation of H2O, illustrating a synergistic reduction of CO2 at the dual-atom sites.