Electrochemical reduction of CO2 in a proton conducting solid oxide electrolyser

Abstract

Synthetic hydrocarbon fuels from CO₂ /H₂O are proposed as alternatives to hydrogen as an energy carrier to enable a carbon neutral energy cycle, given their inherent advantages of high H/C ratio and convenience of storage and transportation. Here we demonstrate the successful electrochemical reduction of CO₂ into CO and CH₄ in a proton conducting solid oxide electrolyser based on BaCe_0.5Zr_0.3Y_0.16Zn_0.04O_3 − δ (BCZYZ) electrolyte and a composite iron/iron oxide cathode. The production of CH₄ and CO reaches 0.07 and 3.25 ml min⁻¹ cm⁻², respectively, with 1.5 A cm⁻² at 614 °C. The overall CO₂ conversion rate in the electrochemical reduction process is 65%.