Modulation of *CH x O Adsorption to Facilitate Electrocatalytic Reduction of CO 2 to CH 4 over Cu-Based Catalysts.

Copper (Cu) can efficiently catalyze the electrochemical CO 2 reduction reaction (CO 2 RR) to produce value-added fuels and chemicals, among which methane (CH 4 ) has drawn attention due to its high mass energy density. However, the linear scaling relationship between the adsorption energies of *CO and *CH x O on Cu restricts the selectivity toward CH 4 . Alloying a secondary metal in Cu provides a new freedom to break the linear scaling relationship, thus regulating the product distribution. This paper describes a controllable electrodeposition approach to alloying Cu with oxophilic metal (M) to steer the reaction pathway toward CH 4 . The optimized La 5 Cu 95 electrocatalyst exhibits a CH 4 Faradaic efficiency of 64.5%, with the partial current density of 193.5 mA cm -2 . The introduction of oxophilic La could lower the energy barrier for *CO hydrogenation to *CH x O by strengthening the M-O bond, which would also promote the breakage of the C-O bond in *CH 3 O for the formation of CH 4 . This work provides a new avenue for the design of Cu-based electrocatalysts to achieve high selectivity in CO 2 RR through the modulation of the adsorption behaviors of key intermediates.