It has been shown that methane can be formed in high amounts by co-electrolysis of CO2 and H2O using a nickel cathode, a CsH2PO4–SiC composite electrolyte and an IrO2 anode. The experimental conditions were 300 °C and 8 bar. The maximum efficiency close to 100% for methane was obtained at a current density of 10–15 mA cm−2. A small amount of hydrogen was formed as the only other product.
Christensen, E., Petrushina, I., Nikiforov, A. V., Berg, R. W., & Bjerrum, N. J. (2020). CsH2PO4 as Electrolyte for the Formation of CH4 by Electrochemical Reduction of CO2. Journal of the Electrochemical Society, 167(4), . https://doi.org/10.1149/1945-7111/ab75fa