Lattice-oriented Contact in Pd/SrTiO3 Heterojunction for Rapid Electron Transfer during Photocatalytic H2 Production

Abstract Semiconductor-metal hybrids have been extensively studied for solar-to-hydrogen conversion. Delicate control on surface of cocatalysts and primary photocatalysts and interface therein can remarkably improve the photocatalytic efficiency. Herein, taking size-controlled Pd nanocubes and SrTiO3 (STO) nanocubes as models, the integration of Pd nanocubes on STO nanocubes (Pd/STO) surface was achieved via an in-situ growth method. The composite photocatalyst presents significant enhancement toward photocatalytic hydrogen production compared to the similar counterpart prepared by simple mechanical self-assembly of Pd and STO, as well as to the pristine STO. The highest hydrogen evolution rate reaches 0.44 mmol h-1 g-1. The success relies on the lattice-oriented growth of Pd nanocubes on STO nanocubes for rapid charge separation from STO to Pd, and accelerated energy and mass exchange on surface of Pd. We believed that the strategy can provide a general guidance to develop more surface and interface-modified metal-semiconductor hybrid systems for hydrogen production.