Revisiting strontium-doped lanthanum cuprate perovskite for the electrochemical reduction of CO2

• We revisited strontium-doped lanthanum cuprate as electrocatalyst for CO2 reduction.
• The compound previously described in the literature was a mixture of two phases.
• These were the tetragonal phases La1−xSrxCuO4 and bilayered La2−xSrxCuO2.6.
• We also extended the range of temperatures (2–40 °C) and pressures (1–43 barg).
• Unlike previous reports, products were not alcohols but ethylene, methane and CO.

The conversion of wind, solar or marine energies to fuels and chemicals can exploit the chemical utilisation of carbon dioxide, and could lead to a more sustainable chemical industry. In particular, electrolytic conversion of CO2 may suit the short-term variability of the energy supply while avoiding issues associated with the large scale storage of hydrogen. Lanthanum cuprate perovskites were described a while ago as promising electrocatalysts for the production of valuable higher alcohols, ethylene and methane from CO2. However, confusion was apparent in the literature as to the nature of the compound that was used, and the data on applied potentials was scarce. In this paper, we report on the electroreduction of CO2 at a gas diffusion electrode loaded with a strontium-doped lanthanum cuprate perovskite in 0.5 M KOH. The compound was prepared following the procedure that was described in previous literature on CO2 electroreduction, and it was characterised as a mixture of bi-layered La1.8Sr0.2CuO4 with tetragonal (La,Sr)CuO2.6. We also extended the range of temperatures (2–40 °C) and pressures (1–43 barg). Methane and ethylene were major products of electroreduction, unlike in previous work where alcohols were dominant. Results and the operational experience from this work should help direct effort towards catalysts that have the advantages of copper metal without its limitations.

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