Enhanced CO2 Electroreduction to CO in Neutral Electrolytes via Sn-Doped Copper Catalysts

Abstract

Converting CO2 to CO through renewable electricity-driven electrocatalysis offers a promising route for carbon cycling and energy storage, though challenges remain in achieving high selectivity and kinetics in neutral electrolytes. Here, we develop a series of composition-tunable CuSn catalysts via a wet-chemical method for efficient CO2 reduction to CO in 1.0 M KHCO3. The optimized 40CuSn catalyst achieves a CO faradaic efficiency (FE) of 85.79% at –0.9 V (vs. RHE, all potentials are reported relative to RHE) with a total current density of –115.4 mA cm–2. Notably, its CO/H2 FE ratio is 11.2 times that of pure Cu, and it exhibits stable performance over 29 h. Characterization reveals that Sn incorporation increases the electrochemically active surface area and modulates the surface electronic structure, promoting *COOH adsorption and *CO desorption while suppressing hydrogen evolution. This work demonstrates an effective non-precious metal catalyst design for selective CO2 electroreduction in neutral media.