Engineering Cu‐In Dual‐Site Catalysts by Dynamic Reconstruction of Cu‐In‐S Quantum Dots for Efficient Electrochemical CO₂ Conversion to Formate

Abstract With the increasing consumption of fossil fuels emitting a large amount of CO₂, electrocatalytic CO₂ reduction (CO₂RR) has become a promising way to reduce carbon emissions. Dual‐site catalysts have been identified as attractive materials for CO₂RR, however, suffering from low selectivity and activity. Herein, Cu‐In‐S quantum dots have undergone in situ dynamic restructuring to construct Cu‐In dual‐site catalysts (Cu_0.15In_0.85 NPs) with highly catalytic activity toward CO₂ electrochemical conversion. Cu_0.15In_0.85 NPs achieved a high Faraday efficiency of 92.3% for formate production at −1.45 V versus RHE, and a high formate partial current density of 245.4 mA cm⁻² at −1.82 V versus RHE in a flow cell. In situ ATR‐SEIRAS spectroscopy and theoretical calculations indicated Cu dopants induced the charge transfer from Cu to In atoms to form the Cu‐In synergistic active sites, thus decreasing the formation energy of OCHO^* and HCOOH^* intermediates, as well as inhibiting the dissociation of water molecules. This work elucidates the optimization mechanism of the electronic structure for dual‐site catalysts and guides the fabrication of highly efficient electrocatalysts for formate production.