Development of BiOI as an effective photocatalyst for oxygen evolution reaction under simulated solar irradiation

Abstract

In this study, crystalline BiOI powders were prepared for photocatalytic O₂ evolution in the presence of NaIO₃ as the electron mediator. BiOI with a microspherical morphology, a layered structure composed of [Bi₂O₂]²⁺ and intercalated I⁻ ions, exhibited a suitable valence band level to generate photoexcited holes for O₂ evolution. Moreover, ruthenium was loaded using the impregnation or photodeposition method to produce RuO₂ as a co-catalyst to improve the photocatalytic activity of BiOI. Photodeposited RuO₂-loaded BiOI showed a high O₂ evolution rate of 2730 μmol h⁻¹ and can be reused eight times in the presence of NaIO₃ under simulated solar irradiation. The high photocatalytic O₂ evolution can be attributed to the highly dispersed RuO₂, which could serve as an effective electron sink, on the surface of BiOI and its enhanced visible light-harvesting ability. Besides, the presence of NaIO₃ in the system was effective to receive photoexcited electrons from RuO₂-loaded BiOI for improving charge separation and hence the O₂ evolution from RuO₂ sites on the BiOI surface. The RuO₂-loaded BiOI with high photocatalytic activity and stability for generating O₂ could be a potential candidate for achieving overall water splitting in a Z-scheme system in the presence of NaIO₃ for solar utilization in the future.