Unlocking Bifunctional Electrocatalytic Activity for CO₂ Reduction Reaction by Win-Win Metal–Oxide Cooperation

Understanding how remarkable properties of materials emerge from complex interactions of their constituents and designing advanced material structures to render desired properties are grand challenges. Metal–oxide interactions are frequently utilized to improve catalytic properties but are often limited to situations where only one component is facilitated by the other. In this work, we demonstrate highly cooperative win-win metal–oxide interactions that enable unprecedented catalytic functionalities for electrochemical CO2 reduction reactions. In a single SnOx/Ag catalyst, the oxide promotes the metal in the CO production mode, and meanwhile the metal promotes the oxide in the HCOOH production mode, achieving potential-dependent bifunctional CO2 conversion to fuels and chemicals with H2 evolution suppressed in the entire potential window. Spectroscopic studies and computational simulations reveal that electron transfer from Ag to SnOx and dual-site cooperative binding for reaction intermediates at the SnOx/Ag interface are responsible for stabilizing the key intermediate in the CO pathway, changing the potential-limiting step in the HCOOH pathway, and increasing the kinetic barrier in the H2 evolution pathway, together leading to highly synergistic CO2 electroreduction.