Metallic Pt and PtO_x dual-cocatalyst-loaded WO₃ for photocatalytic production of peroxydisulfate and hydrogen peroxide

Photocatalytic production of green oxidation reagents as an economical and environmental-friendly process is a promising strategy to replace the traditional production processes. In the present study, a series of 1.0 wt% Pt/WO₃ photocatalysts with different surface chemical states of Pt were successfully fabricated. The different surface metallic Pt (Pt⁰) and oxidized Pt (PtO_x) ratios on WO₃ showed significant effects on the photocatalytic activities for strong oxidants of peroxydisulfate (\( {\text{S}}_{ 2} {\text{O}}_{8}^{2 - } \)) and hydrogen peroxide (H₂O₂) formations. It is proposed that surface Pt⁰ and PtO_x functioned as reduction site for O₂ reduction to H₂O and oxidation site for H₂O oxidation to H₂O₂, respectively, during the photocatalytic process. As a result, a higher surface composition of Pt⁰ prepared using photodeposition (PD) method led to the formation of higher amount of \( {\text{S}}_{ 2} {\text{O}}_{8}^{2 - } \). On the other hand, PtO_x-loaded WO₃ using impregnation (IM) method showed significant formations of \( {\text{S}}_{ 2} {\text{O}}_{8}^{2 - } \) and H₂O₂ simultaneously. This work provided a new idea for the design of noble metal Pt-supported WO₃ for efficiently photocatalytic generation of \( {\text{S}}_{ 2} {\text{O}}_{8}^{2 - } \) and H₂O₂.