Chloride-Promoted High-Rate Ambient Electrooxidation of Methane to Methanol on Patterned Cu–Ti Bimetallic Oxides

The selective electrochemical methane oxidation reaction (MOR) has been challenging due to higher CH 4 activation barriers and lower solubility at ambient conditions. Here, we synthesize a conductive gas-diffusion layer patterned with alternating squares of Cu and Ti oxides to achieve highly selective MOR at interfaces consisting of Cu–Ti bimetallic oxides. We observe high MOR faradaic efficiencies of ∼28% at ambient conditions and ∼72% at near-ambient conditions (40 °C) to value-added products such as CH 3 OH and HCOOH in a Cl – -mediated environment. Density function theory calculations suggest that despite TiO 2 exhibiting barrierless thermochemical methane dissociation, an electrochemical oxidation pathway is likely competitive at high overpotentials. The unprecedented current densities of ∼10 mA/cm 2 for HCOOH and ∼16 mA/cm 2 for CH 3 OH, along with these insights on ambient MOR, will enable the development of highly efficient electrochemical systems for the utilization of CH 4 .