(67e) Synthesis of ‘Microphone’ Structured Bi-Cu Chalcogenide for Efficient Electrocatalytic CO2 Reduction

Electrochemical reduction of CO₂ in alkaline media by using non-precious metal nanoparticles has been attracting tremendous research efforts. Previous work has shown that the electrochemical reduction of CO₂ to formate can be realized over low cost bismuth (Bi)-based catalysts with 0.1M KHCO₃ as the electrolyte, and the Faradic efficiency of formate could reach 90%. Nevertheless, the multimetallic heterostructured Bi catalysts have never been developed. In this work, we synthesized a novel heterostructured Bi-CuS with a microphone-like morphology with a precisely controlled aspect ratio that has never been achieved before (Fig. 1). These Bi-CuS nanoparticles are then used as electrocatalysts for CO₂ reduction in KHCO₃ electrolyte. Our studies showed that the onset potential is 200 mV lower on Bi-CuS catalysts than on bare Bi nanoparticles. Meanwhile, the catalysts present a large current density and high selectivity toward formate in the experiments. By controlling the reaction conditions, e.g., the reaction temperature, the amount of reducing agent and degassing temperature, the optimal Bi-CuS catalyst can achieve over 95% faradic efficiency to formate at -1.7 V (vs Ag/AgCl) with a very high current density 13.3 mA cm^-2, outperforming most of the previous reports.