Glucose-Mediated Synthesis of Hierarchical Porous ZnGa₂O₄ Microspheres for Effective Photocatalytic Removal of Aromatic and Arsenic Pollutants

Porous ZnGa2O4 microspheres (P-ZGO) are synthesized by a facial glucose-mediated microwave hydrothermal method followed by annealing. The morphological, photoelectric and photocatalytic properties of the as-prepared P-ZGO sample are characterized in detail, and the results show that the P-ZGO photocatalyst has a good crystallinity, large species surface area, hierarchical mesoporosity, and distinguished photoelectric properties. Under 254 nm UV irradiation, the P-ZGO sample shows a much higher activity and stability than TiO2 in the photocatalytic degradation of gas-phase aromatic pollutants. The average conversion efficiencies of toluene and benzene over P-ZGO are ~56.6% and ~44.3%, and with corresponding mineralization rates of ~86.3% and ~65.2%, respectively. No remarkable deactivation of P-ZGO is observed in a 60 h heterogeneous photoreaction. Furthermore, the as-prepared P-ZGO sample also shows an excellent photocatalytic efficiency (up to 99.8%) for the liquid-phase As(III) removal from water. The distinguished photocatalytic performance of P-ZGO can be ascribed to its unique electronic structures and hierarchical morphologies. According to the results of our analysis, a possible mechanism is also proposed to elaborate the photocatalytic oxidation process in the pollutants/P-ZGO system.