Selective CO₂ Electromethanation on Surface-Modified Cu Catalyst by Local Microenvironment Modulation

Abstract

Renewable methane synthesized via CO2 electroreduction has the potential to serve as a carbon-neutral medium benefiting from its high energy density. However, challenges remain in achieving high selectivity for electromethanation with low energy input. Here, we found that the adhered ligands on the copper surface can modulate the local microenvironment to realize high rates for methane electrogeneration. The designed glutathione-modified copper electrode exhibited an impressive CO2 to CH4 Faradaic efficiency of 61.7% with a partial current density of 153.7 mA cm–2, which was 35-fold higher than that of pristine copper. Operando Raman spectroscopy experiments suggest that the carboxyl and amino groups of glutathione ligands play a crucial role in regulating intermediate configurations and local proton availability. More broadly, these findings offer routes to alter surface reactivity and create a platform for designing highly selective CO2 electroreduction catalysts.