A Nanocomposite of Bismuth Clusters and Bi 2 O 2 CO 3 Sheets for Highly Efficient Electrocatalytic Reduction of CO 2 to Formate.

The renewable-electricity-driven CO 2 reduction to formic acid would contribute to establishing a carbon-neutral society. The current catalyst suffers from limited activity and stability under high selectivity and the ambiguous nature of active sites. Herein, we report a powerful Bi 2 S 3 -derived catalyst that demonstrates a current density of 2.0 A cm -2 with a formate Faradaic efficiency of 93 % at -0.95 V versus the reversible hydrogen electrode. The energy conversion efficiency and single-pass yield of formate reach 80 % and 67 %, respectively, and the durability reaches 100 h at an industrial-relevant current density. Pure formic acid with a concentration of 3.5 mol L -1 has been produced continuously. Our operando spectroscopic and theoretical studies reveal the dynamic evolution of the catalyst into a nanocomposite composed of Bi 0 clusters and Bi 2 O 2 CO 3 nanosheets and the pivotal role of Bi 0 -Bi 2 O 2 CO 3 interface in CO 2 activation and conversion.