Ga doping disrupts C-C coupling and promotes methane electroproduction on CuAl catalysts

The electrochemical CO2 reduction reaction (CO2RR) provides a route to store intermittent electricity in the form of fuels like methane. We reasoned that disrupting C-C coupling while maintaining high *CO coverage could enhance methane selectivity and suppress the hydrogen evolution reaction (HER). We studied the effect of doping CuAl, a material at the top of the CO2RR activity and selectivity volcano plot, with elements having low *CO binding energies: Au, Zn, and Ga. Encouraged by initial improvements in selectivity tomethane, we optimized the Ga content and showed that the presence of uniformly dispersed Ga is crucial in CO2RR-to-methane performance enhancement. We rule out porosity and roughness and conclude that the presence of Ga in the doped catalysts enables highmethane selectivity. The Ga-doped CuAl catalysts achieve a methane Faradaic efficiency (FE) of 53% by suppressing HER to 23% in neutral electrolyte at 1.4 V versus reversible hydrogen electrode.

Automated summary

The effect of doping CuAl catalysts with elements such as Au, Zn, and Ga on the electrochemical CO2 reduction reaction (CO2RR) was studied. It was found that the presence of uniformly dispersed Ga is crucial in enhancing the performance of CO2RR-to-methane.