A novel photo-thermal chemical looping water splitting technology to achieve efficient and stable hydrogen production under mild condition

The high operational temperatures constrain the practical application of chemical looping steam reforming coupled with water splitting (CLSR-WS) technology. Herein, we first propose a novel photo-thermal CLSR-WS technology to lower the temperature by introducing photothermal coupling catalysis. Under light irradiation, abundant oxygen vacancy (VO) generates on the surface of oxygen carriers (OCs), facilitating the migration of lattice oxygen and the adsorption of gaseous reactants during CLSR. This innovation results in an impressive H2 yield of 8.26 mmol/g OC with 98.14 % purity at 550 °C, comprehensively surpassing the traditional benchmark performance at 800 °C. The reduction of temperature leads to the enhancement in syngas yield and H2 purity, together with a cyclic stability. Co-Fe oxides are found as the suitable OCs for this new technology. Benefitting from the reduced energy of VO formation and bandgap, Co-Fe OCs could utilize the longer-wavelength light to generate VO. Our findings offer a pathway for overcoming the high-temperature bottleneck in CLSR-WS and achieving efficient and stable H2 production under moderate conditions.