Surface Reactions and Water Adsorption on Rh/SrTiO3 for Photocatalytic Water Splitting

Abstract

Photocatalytic water splitting is a promising route for sustainable hydrogen production, but its efficiency is limited by the surface properties of photocatalysts. This study investigates water adsorption and dissociation on Rh-modified SrTiO₃ (100) using X-ray Photoelectron Spectroscopy (XPS) and Metastable Induced Electron Spectroscopy (MIES). Rh/SrTiO₃ samples were prepared, cleaned, thermally treated, and exposed to water under ultra-high vacuum conditions. XPS revealed the formation of surface hydroxyl species following water exposure, while MIES confirmed the absence of molecular water, indicating complete dissociation of adsorbed water. The results demonstrate that Rh promotes active surface sites that facilitate the initial steps of water splitting. These findings improve the understanding of photocatalytic surface reactions and provide insight for the development of more efficient photocatalysts for renewable hydrogen production.