Boosting charge separation of Sr2Ta2O7 by Cr doping for enhanced visible light-driven photocatalytic hydrogen generation

Abstract

In the present study, we report a one-step hydrothermal synthesis of visible-light response Cr-doped Sr₂Ta₂O₇ nanosheets for photocatalytic hydrogen generation. It is discovered that the Cr ion is successfully doped into the Sr₂Ta₂O₇ nanosheet crystal lattice and uniformly distributed without changing the crystal structure and morphology of the Sr₂Ta₂O₇ host. Compared to pristine Sr₂Ta₂O₇, the as-prepared Cr-doped Sr₂Ta₂O₇ photocatalysts show enhanced photocatalytic activity for hydrogen generation under visible-light irradiation. The spectroscopy and Mott–Schottky results reveal that proper Cr doping can narrow the band gap of Sr₂Ta₂O₇ as well as facilitate the separation of photo-generated electrons and holes, thus enhancing the photocatalytic performance under visible-light irradiation. This work provides a simple approach to fabricate visible-light active tantalum-based oxide photocatalysts.