Heterostructured intermetallic CuSn catalysts: high performance towards the electrochemical reduction of CO2 to formate

Abstract

Electroreduction of carbon dioxide (CO₂RR) into fuels and chemicals is an appealing approach to tackle CO₂ emission challenges. To this end, it is critical to develop highly efficient and selective electrocatalysts for the CO₂RR. Herein, we report a simple strategy for the preparation of heterostructured intermetallic CuSn electrocatalysts (Cu₃Sn/Cu₆Sn₅) supported on porous copper foam through an electrodeposition–calcination process. The obtained CuSn intermetallic catalysts demonstrate a faradaic efficiency of 82% and a current density of 18.9 mA cm⁻² at −1.0 V vs. the reversible hydrogen electrode for formate production in 0.1 M NaHCO₃ electrolyte for as long as 42 h. By using a gas diffusion electrode and 1 M KOH electrolyte, the current density of this catalyst for formic acid production can reach values as high as 148 mA cm⁻². Density functional theory calculations show that the moderate Gibbs free energy of hydrogen adsorption on the heterostructured Cu₃Sn/Cu₆Sn₅ catalysts not only suppresses hydrogen evolution, but also favors the production of formic acid. This study demonstrates a straightforward approach to the preparation of high-performance electrocatalysts towards the selective electroreduction of CO₂ to formate.