Cu@Bi nanocone induced efficient reduction of CO2 to formate with high current density

Abstract

Electrochemical conversion of CO2 into formate provides an attractive approach to store renewable energy in the form of valuable chemical products, but searching for inexpensive catalytic material that can accomplish the reduction of CO2 to formate with a high selectivity at high current densities remains a challenge. Herein, spiky Cu@Bi nanocone with a curvature radius of 10 nm were prepared through facile electrochemical coating of a thin layer of Bi over a substrate of Cu nanocone. The Cu@Bi nanocone exhibits excellent performance for CO2 reduction, achieving a high faradaic efficiency > 90 % for formate formation in the potential range from −0.75 to −0.95 V, and gives a faradaic efficiency of 96.9 % at −0.95 V at a current density of -31.9 mA cm−2. The superior performance probably be attributed to the unique conic tip structure, as indicated by comparison to the structure of bulk Bi.