High-efficiency electrochemical methane conversion using Fe2O3-based catalysts assisted by thermochemical active oxygen

Abstract

Direct methane-alcohol conversion is urgently needed not only for efficient use of methane but also for a sustainable environment. Here, we present hybrid electrochemical methane oxidation with thermochemical generation of active oxygen by employing an Fe2O3-based catalyst with a CO32- oxygen source. A mechanistic study, including an electrochemical analysis, elucidates the reaction pathway in which the CO32- activates methane by supplying O* through thermal dissociation over the Fe2O3 catalyst, while an electrochemical potential applied to the Fe2O3 catalyst promotes the subsequent methane–ethanol conversion. We demonstrate that doping the catalyst with oxophilic Zr into the catalyst enhances ethanol conversion by stabilizing the hydroxyl-containing intermediates. In room-temperature electrochemical methane conversion, we achieve an ethanol production rate of 1677 μmol/gcat/hr (the total production rate for oxygenates is 1831 μmol/gcat/hr) with a selectivity of 91 % and an 87 % Faraday efficiency conversion.