Enriched Surface Oxygen Vacancies of Fe₂(MoO₄)₃ Catalysts for a PDS-Activated photoFenton System

The environmentally benign Fe₂(MoO₄)₃ plays a crucial role in the transformation of organic contaminants, either through catalytically decomposing oxidants or through directly oxidizing the target pollutants. Because of their dual roles and the complex surface chemical reactions, the mechanism involved in Fe₂(MoO₄)₃-catalyzed PDS activation processes remains obscure. In this study, Fe₂(MoO₄)₃ was prepared via the hydrothermal and calcine method, and photoFenton degradation of methyl orange (MO) was used to evaluate the catalytic performance of Fe₂(MoO₄)₃. Fe₂(MoO₄)₃ catalysts with abundant surface oxygen vacancies were used to construct a synergistic system involving a photocatalyst and PDS activation. The oxygen vacancies and Fe²⁺/Fe³⁺ shuttle played key roles in the novel pathways for generation of •O₂^-, h⁺, and ¹O₂ in the UV-Vis + PDS + FMO-6 photoFenton system. This study advances the fundamental understanding of the underlying mechanism involved in the transition metal oxide-catalyzed PDS activation processes.