A theoretical study on tetragonal BaTiO3 modified by surface co-doping for photocatalytic overall water splitting.

Density functional theory calculations are applied to study the influence of co-doping on the stability, electronic structure, and photocatalytic activity of tetragonal BaTiO 3 (001) surface. The results show that the formations of all the metal-nonmetal co-doped BaTiO 3 (metal = V, Nb, Ta, Mo, W and nonmetal = N, C) are energetically favorable. Most of co-doped surfaces have remarkable narrower bandgaps than the pristine surface, which favors the movement of absorption edge to the visible light region. Co-doped systems have better affinity toward H 2 O than the pure surface. For most of the studied systems, the active sites of HER and OER are the O site and the Ti site adjacent to the metal dopant, respectively. Surface co-doping results in remarkable decreases in | Δ G H | of HER and the OER overpotential of BaTiO 3 (001) surface. This work proposes the potential application of BaTiO 3 modified by surface co-doping as efficient photocatalysts for overall water splitting. Surface codoping in BaTiO 3 remarkably enhances the activities of HER and OER. [Display omitted] • Surface codoping can efficiently reduce the band gap of BaTiO 3. • Co-doped BaTiO 3 surfaces have better affinity toward H 2 O than the pure one. • Co-doped BaTiO 3 involving Mo or W remarkably improve the OER performance. • Co-doped surfaces exhibit higher activities in HER than the pure BaTiO 3 surface. [ABSTRACT FROM AUTHOR]