Chalcogens doped BaTiO₃ for visible light photocatalytic hydrogen production from water splitting

The pristine BaTiO₃ has been experimentally confirmed to catalyze hydrogen production from water splitting, but the reaction cannot be driven by the visible light because of the wide energy band gap of BaTiO₃. To understand the feasibility of the reaction driven by the visible light of the strongest part of the solar energy, we have investigated the effect of different concentrations of oxygen group element dopants on the electronic and optical properties of BaTiO₃ by using first-principles density functional theory calculations with meta-GGA + MBJ potential. The formation energy of each doped structure is calculated to examine the feasibility of synthesis in energy. The energy band gaps and the energy positions of conduction and valence bands are calculated and the results reveal that all the structures except the one that doped with 5 at% Te satisfy the conditions of water splitting although the energy band gaps of the doped BaTiO₃ decrease obviously. The partial charge distributions of conduct band maximum and valence band minimum are used to demonstrate the electron-hole separation. The absorption coefficients are calculated for all the considered structures. The results demonstrate that the doped chalcogens can significantly enhance the absorption in visible light range, which implies that the doped BaTiO₃ are promising to catalyze the hydrogen production from water splitting driven by solar energy.