Achieving highly selective electrochemical CO2 reduction to C2H4 on Cu nanosheets

The conversion of CO 2 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 CO 2 reduction reaction (ECO 2 RR). The derived Cu nanosheets demonstrate much higher selectivity for C 2 H 4 production than commercial CuO derived Cu powder, with an optimum Faradaic efficiency of 56.2% and a partial current density of C 2 H 4 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 C 2 H 4 formation.