Morphology, interface, and energy field engineering of ternary oxide photoanodes for efficient photoelectrochemical water splitting

Photoelectrochemical (PEC) water splitting, utilizing solar energy to dissociate water, is a promising approach for clean hydrogen production. Ternary oxide photoanodes serve as key materials due to their compositional versatility, stability, and electrochemical properties. Overcoming current efficiency and stability limitations, however, requires multifaceted structural and functional optimization. This review comprehensively summarizes recent progress in high-performance ternary oxide photoanodes, systematically discussing four core enhancement strategies: morphology engineering, chemical composition tuning, interface layer loading engineering, and energy field-assisted techniques. Specifically, morphology engineering analyzes surface optimization (including facet engineering) and bulk control for improved charge separation/transport. Chemical tuning via doping and defect engineering enhances light absorption and charge dynamics. Interface layer loading engineering employs mono- and multi-layer structures to boost reaction selectivity and stability. Furthermore, we highlight the beneficial roles of applied energy fields, including thermal, built-in electric, pressure, and magnetic fields, in promoting water splitting. Prospectively, synergistic multiscale design combined with interdisciplinary collaboration promises to substantially enhance the PEC efficiency and long-term stability of ternary oxide photoanodes. This review provides critical insights for developing next-generation photoanodes, advancing PEC technology towards practical application.