Surface oxophilicity regulation decoupling selective CO2 electroreduction towards ethanol and boosting Li-CO2 batteries performance

Cu-based electrocatalysts possesses superior potential to produce energy-dense fuels and value-added chemicals in electrocatalytic CO 2 reduction reaction (eCO 2 RR). Nevertheless, the desperately desired target C 2 selectivity is fundamentally constrained by inevitable hydrogen evolution reaction (HER), C 1 products competition and sluggish reaction kinetics, especially for ethanol. Herein, the strategy of introducing Mg on CuO is proposed to aim at modulating adsorption energetics of oxygen-associated active species, which can effectively suppress competing pathways while boosting ethanol production. Benefitting from the modified electronic structure and lattice compressive strain induced by Mg-doping, Mg 0.34 @CuO exhibited 77.5 % of C 2 FE with remarkable stability, in which FE C2H5OH could reach 48.5 % with total current density of 245.5 mA cm −2 . Density functional theory (DFT) calculation revealed that Mg-doped Cu surface exhibits multiple catalytic function, such as suppressed HER, increased surface CO coverage and accelerated H 2 O dissociation, which can be conducive to promote ethanol production. Incorporation of Mg significantly reduces the energy barrier for asymmetric CO-CHO coupling reaction and stabilizes C-O bond in *CH 2 CHO intermediate (shared by ethylene (C 2 H 4 ) and ethanol (C 2 H 5 OH)) by enhancing d-p orbital coupling, thus prioritizing C 2 H 5 OH pathway. Furthermore, it could achieve a high discharge capacity of 14944 mAh g −1 and stable charge-discharge operation of 153 cycles in Li-CO 2 batteries that utilize Mg 0.34 @CuO as cathode material. This work demonstrates a generalizable approach to regulate eCO 2 RR activity and selectivity, and meanwhile shows great application potential in rechargeable Li-CO 2 batteries.