High-Throughput DFT of Solar Thermochemical Perovskite Oxides: Comparison of Computed and Experimental Thermodynamics

Thermochemical water-splitting (TWS) offers a renewable alternative to fossil fuels by utilizing solar energy for the production of hydrogen via a two-step redox reaction sequence involving a metal oxide. Current and past efforts have been aimed at identifying the best compounds for such reactions based on thermodynamic and kinetic properties. In this context, high throughput density functional theory (HT-DFT) represents an attractive tool for a quick and efficient refinement of the pool of potential candidates. This work concentrates on ABO3 perovskite compounds, conducting a high throughput study of their reduction enthalpy, and selecting a group of 12 compounds for a critical, quantitative comparison with experimental data generated by our collaborators. Building on, and significantly extending, a previous HT-DFT study, we have confirmed the use of high throughput DFT as a reliable method for screening for potential candidates for water splitting reactions, while also demonstrating the importance of choosing the appropriate structure for the compound under investigation. Furthermore, we provided predictions for several promising compounds, highlighting the crucial role played by the B site cation and its oxidation state.