Ca- and Ga-Doped LaMnO₃ for Solar Thermochemical CO₂ Splitting with High Fuel Yield and Cycle Stability

Solar thermochemical CO2 splitting to produce fuels is an effective route to reduce carbon emission. However, it is still a daunting challenge to achieve a high CO yield and good cycle stability simultaneously at a low reaction temperature. Here, Ca- and Ga-doped LaMnO3 is introduced for solar thermochemical CO2 splitting with an ultrahigh CO yield and excellent cycle stability at a moderate operation temperature. The average CO production reaches 513 μmol/g for La0.6Ca0.4Mn0.8Ga0.2O3 when operating between 1350 and 1050 °C. Such a high value sets a record among directly measured thermochemical CO production in the literature with the temperature swing limited within 300 °C. No obvious performance deterioration over eight cycles is observed due to stable structures. The high CO production of La0.6Ca0.4Mn0.8Ga0.2O3 can be attributed to the transition of the surface reaction to internal bulk diffusion induced by Ca doping and enhanced non-stoichiometry due to Ga doping. This work provides a promising alternative for solar thermochemical CO2 splitting with high fuel yield and cycle stability.