Plasma Electrocatalytic Oxidation of Methane to Methanol

High Resolution Image Download MS PowerPoint Slide Selective electrocatalytic conversion of methane (CH 4 ) to methanol (CH 3 OH) using renewable electricity under ambient conditions offers an option of interest in providing methane-derived molecules that are readily transported. The high thermodynamic stability and chemical inertness of CH 4 today limit both the productivity and selectivity. Here, we report a hybrid plasma-electrocatalytic system that enables CH 4 -to-CH 3 OH conversion under ambient conditions. By using plasma to preactivate CH 4, the challenge transits from electrochemical CH 4 oxidation to methyl radical ( • CH 3 ) conversion. We document the coupling of short-lived CH 3 radicals and adsorbed hydroxyl groups (*OH) at the plasma–catalyst–electrolyte interface. We achieve >90% faradaic efficiency in the electrochemical stage of CH 3 radicals to CH 3 OH conversion and a methanol yield on total electrical energy of 60 g methanol kWh –1, with plasma energy accounting for 90% of the total electricity. We operated the hybrid plasma-electrocatalytic system for 890 h with an average faradaic efficiency of 86%. This study presents a new radical-based pathway and contributes to activate-and-electrolyze conversion reactions.