(Invited) Electrocatalytic Reduction of Carbon Dioxide over Aluminum-Added Coppor Oxide Gas Diffusion Electrode

Abstract

Electrochemical cells are the key technologies for construction of carbon neutral society to produce hydrogen from water and produce useful chemicals from carbon dioxide utilizing renewable energy. Copper species are the unique catalysts for electrochemical carbon dioxide reduction reaction (CO2RR) with capable of producing C2+ products such as ethanol and ethylene. Selective production of target chemical is one of the most important requirements for the catalysts, and addition of different elements and surface modifications have been reported to be beneficial for the selective production.In the present study, copper oxides-based catalysts prepared with electroless plating techniques were examined for electrochemical CO2RR. To conduct CO2RR at relatively high current densities, the catalysts were examined in the form of gas diffusion electrode (GDE). The Cu2O based GDE was prepared by the combination of physical vapor deposition and electroless plating on hydrophobized carbon paper coated with mesoporous carbon layer. After the electroless plating treatment, the metal precursors were successfully converted to core-shell structured electrocatalyst with Cu2O shell and Cu core. By introducing different elements such as aluminum to the precursor, metallic Cu, the different element added catalysts were successfully prepared in the shape of GDE. Addition of different element significantly improved durability of the core-shell structured catalysts and, as a result, faradaic efficiency of ethylene of 24 hours after starting electrolysis was increase from 32% to 47% under applying cathodic current of 260 mAcm-2. Further surface modifications with Nafion enhanced the durability and the faradaic efficiency of ethylene maintained >50% for over 48 hours and reached about 60% in maximum.In the presentation, we will discuss about the detailed structure of the electrocatalysts, results of full-cell test, and longer durability test over 100 hours.