Accuracy of DFT computed oxygen-vacancy formation energies and high-throughput search of solar thermochemical water-splitting compounds

Abstract

The computation of the oxygen vacancy formation energy using density functional theory is a critical factor in applications like solar thermochemical hydrogen production. However, when we calculate it using structures that are dynamically unstable, results in artificially reduced values and lack of convergence with cell size. By comparing the calculated values with experimental data, the authors can clearly see the importance of using dynamically stable structures for accurate calculations. This comparison also validates the reliability of density functional theory calculations. Furthermore, using a high-throughput approach, the authors perform such calculations to identify new candidates for solar thermochemical hydrogen production among ABO${}_{3}$ perovskite materials, demonstrating the striong influence of B-site cations on the oxygen vacancy formation energy.