High Throughput Preparation of Bi-Sb Alloy Films for the Electrocatalytic Reduction of CO 2 to Formate

Bi is considered as a highly active and selective electrocatalyst for CO 2 reduction reaction (CO 2 RR), 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 CO 2 reduction. In contrast to pure Sb catalyst, the Bi-Sb alloys substantially suppress HER and promote the pathway of CO 2 -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 CO 2 to formate, and even shows a higher formate activity than that of pure Bi. Especially, the Bi 45 Sb 55 catalyst exhibits a partial current density of formate formation of 58.0 mA cm −2 and 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 −2 is achieved at a moderate overpotential of 859 mV, exhibiting great potential for CO 2 RR process to practical applications. The present work could provide guidelines for the design of Bi-Sb alloy catalysts for efficient CO 2 RR.