Influence of surface restructuring on the activity of SrTiO3 photoelectrodes for photocatalytic hydrogen reduction

Abstract

Perovskite photoelectrodes are being extensively studied in search for photocatalytic materials that can produce hydrogen through water splitting. The solar-to-hydrogen efficiency of these materials is critically dependent on the electrochemical state of their surface. Here, we develop an embedded quantum-mechanical approach using the self-consistent continuum solvation (SCCS) model to predict the relation between band alignment, electrochemical stability, and photocatalytic activity taking into account the long-range polarization of the semiconductor electrode under electrical bias. Using this comprehensive model, we calculate the charge-voltage response of various reconstructions of a solvated SrTiO3 surface, revealing that interfacial charge trapping exerts primary control on the electrical response and surface stability of the photoelectrode. Our results provide a detailed molecular-level interpretation of the enhanced photocatalytic activity of SrTiO3 upon voltage-induced restructuring of the semiconductor-solution interface.