Electrochemical reduction of CO2 in a proton conducting solid oxide electrolyser

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 BaCe0.5Zr0.3Y0.16Zn0.04O3 − 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%.