LAUSR

Abstract Owing to favorable water-splitting activity at low concentration of steam, LaFeO3 represents promising solar thermochemical (STC) materials to achieve commercial energy conversion efficiency (ηsolar-to-fuel) of 20%, which is far from reaching up to now. Here we propose possible strategy to improve ηsolar-to-fuel of LaFeO3 via solving the scarcity of its water-splitting kinetic and thermodynamic characteristics. The detailed pathway of water-splitting and H2 production around oxygen vacancy site of LaFeO3 is firstly revealed, where the migration of surface H atom is determined as rate controlling step with activation energy of 147.24 kJ/mol. Then, within the good consistent between our thermodynamic calculations and previous experiments, we find that both reduction and water-splitting steps are endothermic, and the conversion ratio of water to hydrogen should be larger than 10% to ensure ηsolar-to-fuel>20%. In addition, the calculated ηsolar-to-fuel with the consideration of water-splitting kinetics shows that only the isothermal condition of 1400 K is beneficial for increasing ηsolar-to-fuel up to 20%. Our work demonstrates the potential of LaFeO3 in efficient H2 production and provides key metrics for further improvement along the pathway to commercialization.