Electro‐Reconstruction‐Induced Strain Regulation and Synergism of Ag‐In‐S toward Highly Efficient CO2 Electrolysis to Formate

Abstract Formate production from direct CO 2 electrolysis is economically appealing yet challenging in activity, selectivity, and stability. Herein, sulfur and silver dual‐decorated indium quasi‐core–shell structures with compressive or tensile strain are rationally designed for efficiently electrocatalyzing CO 2 to formate. The introduction of Ag and S increases the current density, Faradaic efficiency, and operational stability of formate both in H‐cell and flow cell systems. As a result, the optimized Ag‐In‐S bimetallic catalysts exhibit the FE HCOO − of ≈94.0% with a J HCOO − of more than −560.0 mA cm −2 at ≈−0.951 V RHE in the flow cell system, which far surpasses the undecorated In catalyst. The experimental and theoretical calculations provide a deeper understanding of the role of the interfacial strain between In or In 4 Ag 9 shell and AgIn 2 core in boosting the electrocatalytic CO 2 reduction efficiency, in which the formation energy of *OCHO intermediate decreases and the charge transfer rate is accelerated by interface strain.