High Throughput Preparation of Bi-Sb Alloy Films for the Electrocatalytic Reduction of CO2to Formate

Bi is considered as a highly active and selective electrocatalyst for CO2reduction reaction (CO2RR), and Sb has great development potential. In this study, we fabricated a series of Bi-Sb alloy films by magnetron co-sputtering and further explored their electrocatalytic performances in CO2reduction. In contrast to pure Sb catalyst, the Bi-Sb alloys substantially suppress HER and promote the pathway of CO2-to-formate. The formate selectivity increases with the increase of Bi content. When the content of Bi reaches about 40 at%, the Bi-Sb alloy exhibits the highest ability to convert CO2to formate, and even shows a higher formate activity than that of pure Bi. Especially, the Bi45Sb55catalyst exhibits a partial current density of formate formation of 58.0 mA cm−2and a formate selectivity of 76.7% at −1.0 V vs RHE. A remarkable formate selectivity reaches up to over 95% in the flow cell, and a formate current density of 500 mA cm−2is achieved at a moderate overpotential of 859 mV, exhibiting great potential for CO2RR process to practical applications. The present work could provide guidelines for the design of Bi-Sb alloy catalysts for efficient CO2RR.