Theoretical research aiming at high‐efficiency hydrogen production using solar thermochemical energy for the goal of sustainable energy supply

This study aims to theoretically explain the experimental facts of the thermal redox reaction by means of the first principle calculation called Discrete Variational Xα (DV‐Xα) molecular orbital calculation. It is indicated that the relation between the effects of the transition metal doping into cerium oxide (CeO2: ceria) and the hydrogen gas production in the thermal redox reaction. The calculation results showed that the bonding between the metal ions and the oxygen ions in the doped ceria is stronger than that shown in the non‐doped ceria. In addition, the Mndoped ceria showed the most robust bonding among the transition metal (Mn, Fe, Co, Ni) doped ceria. These results suggested that the magnitude of the crystal structure stabilization affects the redox reaction efficiency in each doped ceria. We summarized that the bonding strength in the doped ceria is one of the critical points considering the redox reaction efficiency.