Xinbo Li

The efficient electrochemical reduction of carbon dioxide to formate under mild conditions is a promising approach to mitigate the energy crisis, but requires the use of high-performance catalysts. The selectivity and activity of catalysts can be enhanced through multi-metal doping, further advancing the electrochemical reduction of CO₂ to formate. This study demonstrates a co-electrodeposition strategy for synthesizing SnBi electrocatalysts on pretreated copper foam substrates, systematically evaluating how the Sn²⁺/Bi³⁺ molar ratio in the electrodeposition solution and the applied current density affect the catalytic performance for CO₂-to-formate conversion. Optimal performance was achieved with a molar ratio of Sn²⁺ to Bi³⁺ of 1:0.5 and a deposition current density of 3 mA cm⁻², resulting in a formate Faradaic efficiency (FE_formate) of 97.80% at −1.12 V (vs. RHE) and a formate current density of 26.9 mA·cm⁻². Furthermore, the Sn₁Bi_0.50-3 mA·cm⁻² electrode demonstrated stable operation at the specified potential for 9 h, maintaining a FE_formate above 90%. Compared to previously reported metal catalysts, the SnBi catalytic electrode exhibits superior performance for the electrochemical reduction of CO₂ to HCOOH. The study highlights the significant impact of the metal ion molar ratio and deposition current density in the electrodeposition process on the characteristics and catalytic performance of the electrode.