Achieving high current density for electrocatalytic reduction of CO2 to formate on bismuth-based catalysts

Abstract

Electrocatalytic reduction of CO 2 to formate is an attractive avenue for CO 2 utilization. Unfortunately, existing catalysts suffer from low faradic efficiency of formate production at high current density. Here, we report a general strategy for preparing the Bi 2 O 2 CO 3 nanosheet (BOC-NS) with abundant oxygen vacancies through in situ electrically driven conversion of the BiPO 4 precursor. The converted BOC-NS displays high faradic efficiency of formate (FE HCOO − ) (∼100%) over a wide potential region in an H-type cell and achieves a formate partial current density of −930 mA cm −2 with a FE HCOO − of 93% at −1.55 V RHE in a flow cell. Experimental results and density functional theory (DFT) calculations confirm that the BOC-NS surface with abundant oxygen vacancies benefit formate production, which stems from fast reaction kinetics toward the formation of ∗OCHO intermediate on defective Bi 2 O 2 CO 3 nanosheets. This work provides helpful guidance for designing efficient electrocatalysts via in situ electrochemical transformation. Defective Bi 2 O 2 CO 3 nanosheet is prepared through in situ conversion of BiPO 4 Bi 2 O 2 CO 3 serves as a stable and active phase for CO 2 RR to formate BOC-NS displays superior CO 2 RR performance toward formate DFT study confirms that oxygen vacancy benefits formate production Fan et al. present the production of defective Bi 2 O 2 CO 3 nanosheet through in situ transformation of BiPO 4 , which achieves a high formate partial current density of −930 mA cm −2 with a faradic efficiency of 93% in a flow cell. This material contains beneficial oxygen vacancies and shows improvement over existing catalysts that suffer from low faradic efficiency of formate production at high current density.