Novel all-solid-state Z-scheme SnO₂/Pt/In₂O₃ photocatalyst with boosted photocatalytic performance on water splitting and 2,4-dichlorophenol degradation under visible light

Fabricating Z-scheme photocatalytic system is of great significance for water splitting and degradation of organic pollutants. However, it is highly challenging to select suitable materials to form Z-scheme photocatalysis systems due to the harsh requirement for band edge levels alignment and interfacial contact. In this work, a novel all-solid-state Pt-bridge SnO₂/Pt/In₂O₃ Z-scheme photocatalyst was prepared by an ingenious in situ deposition and photo-reduction protocol. The physicochemical properties of prepared materials were characterized via SEM, TEM, BET, DRS, PL, and EIS. It is revealed that the visible light absorption capacity of prepared composites was remarkably enhanced due to the localized surface plasma resonance effect of Pt nanoparticles. Moreover, such Pt nanoparticles act as the electron mediator of photogenerated carriers, and the photogenerated electron hole pairs of SnO₂/Pt/In₂O₃ Z-scheme photocatalysts can be effectively separated, which hence reserving the most favorable reductive and oxidative reaction sites. The photocatalytic degradation efficiency of 2,4-dichlorophenol (50 mg L⁻¹) over SnO₂/Pt/In₂O₃ under visible light reaches 90% in 180 min, and the optimal photocatalytic H₂ generation rate reaches 967.018 μmol h⁻¹ g⁻¹, respectively more than 9.36 and 19.40 times higher than that of pure In₂O₃ (103.358 μmol h⁻¹ g⁻¹) and SnO₂ (49.847 μmol h⁻¹ g⁻¹). In addition, the stability experiments showed that the H₂ generation rate of the SnO₂/Pt/In₂O₃ Z-scheme photocatalyst after five cycles has only decreased by 8.96%. This work not only demonstrates a facile and eco-friendly strategy to prepare highly active and stable photocatalyst, but provides a new viewpoint about designing and constructing novel Z-scheme photocatalytic materials.