Towards Visible-Light Water Splitting Photocatalysts: Band Engineering of two-dimensional A5B4O15 perovskites

Photocatalytic water splitting is a promising route to achieve renewable hydrogen production. In this work, a series of A5B4O15 (A=Ca, Sr, Ba; B=V, Nb, Ta) layered perovskite materials, were investigated through density functional theory computations. We revealed that changing B ions can modify the band gap, and A-ion substitution can tune the band-edge position. Therefore, through A/B ion combination, we can realize the band engineering of A5B4O15 materials. Electron/hole effective mass and water adsorption of A5B4O15 materials were also explored. Further investigations suggest that Ca5V4O15 nanosheet, with an appropriate band gap and an optimal band-edge position, would be a promising photocatalyst for visible-light water splitting.