Modulation of *CHXO Adsorption to Facilitate Electrocatalytic Reduction of CO2 to CH4 over Cu-Based Catalysts

Copper (Cu) can efficiently catalyze the electrochemical CO2 reduction reaction (CO2RR) to produce value-added fuels and chemicals, among which methane (CH4) has drawn attention due to its high mass energy density. However, the linear scaling relationship between the adsorption energies of *CO and *CHxO on Cu restricts the selectivity toward CH4. 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 CH4. The optimized La5Cu95 electrocatalyst exhibits a CH4 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 *CHxO by strengthening the M-O bond, which would also promote the breakage of the C-O bond in *CH3O for the formation of CH4. This work provides a new avenue for the design of Cu-based electrocatalysts to achieve high selectivity in CO2RR through the modulation of the adsorption behaviors of key intermediates.

Automated summary

This paper presents a controllable electrodeposition approach to alloying Cu with an oxophilic metal to steer the CO2 reduction reaction towards methane production. The optimized La5Cu95 electrocatalyst exhibits a high CH4 Faradaic efficiency of 64.5%, with a partial current density of 193.5 mA cm-2. The introduction of oxophilic La assists in lowering the energy barrier for *CO hydrogenation and promotes the formation of CH4.