Ca2+ and Ga3+ doped LaMnO3 perovskite as a highly efficient and stable catalyst for two-step thermochemical water splitting

Abstract

High performance and stable catalysts for two-step thermochemical water splitting are key to synthesising direct fuels in the form of H2 or liquid hydrocarbon fuels by the Fischer–Tropsch process. Herein, we designed and synthesised LaMnO3 perovskite structured oxides doped on both the A and B sites for two-step thermochemical water splitting. First, Ca2+, Sr2+ and Ba2+ divalent cations were successfully doped on the A site of LaMnO3 and the thermochemical water splitting performances were analysed. After that, Al3+ and Ga3+ ions were doped on the B site of the perovskites produced in the first step. Through this strategy, a novel perovskite composition (La0.6Ca0.4Mn0.8Ga0.2O3) was found with remarkable water splitting performance, producing 401 μmol g−1 of H2 at low thermochemical cycle temperatures between 1300 and 900 °C. The as-prepared perovskite exhibits twelve times higher H2 production than the benchmark CeO2 catalyst under the same experimental conditions. This novel perovskite is also capable of maintaining steady-state redox activity during the water splitting cycles.