Achieving highly selective electrochemical CO2 reduction to C2H4 on Cu nanosheets

The conversion of CO2 into value-added chemicals coupled with the storage of intermittent renewable electricity is attractive. CuO nanosheets with an average size and thickness of ti 30 and -20 nm have been developed, which are in situ reduced into Cu nanosheets during electrochemical CO2 reduction reac-tion (ECO2RR). The derived Cu nanosheets demonstrate much higher selectivity for C2H4 production than commercial CuO derived Cu powder, with an optimum Faradaic efficiency of 56.2% and a partial current density of C2H4 as large as 171.0 mA cm-2 in a gas diffusion flow cell. The operando attenuated total reflectance-Fourier transform infrared spectra measurements and density functional theory simulations illustrate that the high activity and selectivity of Cu nanosheets originate from the edge sites on Cu nanosheets with a coordinate number around 5 (4-6), which facilitates the formation of *CHO rather than *COH intermediate, meanwhile boosting the C -C coupling reaction of *CO and *CHO intermediates, which are the critical steps for C2H4 formation. (c) 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences Published by Elsevier B.V. All rights reserved.

Automated summary

The conversion of CO2 into value-added chemicals coupled with the storage of intermittent renewable electricity is attractive. CuO nanosheets with an average size and thickness of 30 and -20 nm have been developed, which are in situ reduced into Cu nanosheets during electrochemical CO2 reduction reaction (ECO2RR). The derived Cu nanosheets demonstrate much higher selectivity for C2H4 production than commercial CuO derived Cu powder, with an optimum Faradaic efficiency of 56.2% and a partial current density of C2H4 as large as 171.0 mA cm-2 in a gas diffusion flow cell. The operando attenuated total reflectance-Fourier transform infrared spectra measurements and density functional theory simulations illustrate that the high activity and selectivity of Cu nanosheets originate from the edge sites on Cu nanosheets with a coordinate number around 5 (4-6), which facilitates the formation of *CHO rather than *COH intermediate, meanwhile boosting the C -C coupling reaction of *CO and *CHO intermediates, which are the critical steps for C2H4 formation. (c) 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences Published by Elsevier B.V. All rights reserved.