Construction of SrTiO3–LaCrO3 Solid Solutions with Consecutive Band Structures for Photocatalytic H2 Evolution under Visible Light Irradiation

Abstract

SrTiO3–LaCrO3 continuous solid solutions with LaCrO3 content ranging from 0.00 to 1.00 were prepared via a polymerized complex method. The light absorption ability of SrTiO3 was improved by the consecutive tuning of the bandgap upon the introduction of LaCrO3 (up to 570 nm). The solid solutions exhibited significantly enhanced photocatalytic activities for H2 evolution under visible light irradiation, with an optimized H2 evolution rate of 1368 μmol h−1 g−1 obtained when LaCrO3 content was 0.10 (with 1 wt% Pt as cocatalyst), corresponding to an apparent quantum yield of 3.68% at 400 nm. Supported by comprehensive characterization, the improved photocatalytic performance was attributed to the simultaneously adjusted conduction band and valance band originating from the hybridization of Cr 3d, Ti 3d and O 2p orbitals, as well as the accelerated separation and migration of photogenerated charge carriers derived from the distortion of TiO6 octahedra.