Single Atom Bi Decorated Copper Alloy Enables C−C Coupling for Electrocatalytic Reduction of CO2 into C2+ Products**

Abstract Single atom alloy (SAA) catalysts have been recently explored for promotion of various heterogeneous catalysis, but it remains unexplored for selective electrocatalytic reduction of carbon dioxide (CO 2 ) into multi‐carbon (C 2+ ) products involving C−C coupling. Herein we report a single‐atomic Bi decorated Cu alloy (denoted as BiCu‐SAA) electrocatalyst that could effectively modulate selectivity of CO 2 reduction into C 2+ products instead of previous C 1 ones. The BiCu‐SAA catalyst exhibits remarkably superior selectivity of C 2+ products with optimal Faradaic efficiency (FE) of 73.4 % compared to the pure copper nanoparticle or Bi nanoparticles‐decorated Cu nanocomposites, and its structure and performance can be well maintained at current density of 400 mA cm −2 under the flow cell system. Based on our in situ characterizations and density functional theory calculations, the BiCu‐SAA is found to favor the activation of CO 2 and subsequent C−C coupling during the electrocatalytic reaction, as should be responsible for its extraordinary C 2+ selectivity.