On-Site Growth of a TaON Nanoshell on ZrO2 Particles for Photocatalytic Water Splitting

Low-dimensional nanostructuring has emerged as a promising approach to enhance the photocatalytic performance of transition metal oxynitrides, a class of widely investigated visible-light-responsive photocatalysts. Despite their potential, the synthesis of nanostructured oxynitride materials remains a great challenge. In this study, we present a novel NH 4 Cl-assisted vacuum nitridation method for in situ growth of an ultrathin TaON layer on particulate ZrO 2, resulting in the formation of TaON@ZrO 2 core@shell nanostructures. By controlling the Ta metal content in the precursor, the thickness of the TaON shell can be adjusted within the range of 1–3 nm. Comprehensive Raman spectroscopy and EXAFS analyses confirm the successful synthesis of well-defined and phase-pure TaON nanocrystals. Compared to conventional bulk TaON particles, the nanostructured TaON@ZrO 2 exhibits significantly enhanced photocatalytic activity for visible-light-driven water splitting. Surface photovoltage measurements further demonstrate improved charge separation efficiency, which is attributed to the unique nanostructure design. This work not only provides a robust strategy for the controlled synthesis of TaON@ZrO 2 nanoparticles but also underscores the critical role of nanostructuring in optimizing the water splitting performance of oxynitride-based photocatalysts.