A heterostructured WO3–SnO2 nanocomposite for the efficient photocatalytic production of H2O2 under visible light

Abstract

Hydrogen peroxide (H₂O₂) is a versatile oxidant that is clean, environmentally friendly and typically produced industrially via the anthraquinone oxidation (AO) method. As opposed to the highly polluting conventional ways, the visible light photocatalytic reaction is a viable method for achieving sustainable H₂O₂ generation. Herein, visible light active WO₃–SnO₂ nanocomposites (WSN) were synthesized through a facile process for H₂O₂ production. The nanoscale particles of WO₃ and SnO₂ exhibit crystalline and mesocrystalline states, respectively, in the composites and, which are uniformly dispersed and tightly bound, forming the unique heterostructures, providing strong visible light absorption and abundant substrate adsorption and reaction sites. The composite exhibited the highest apparent catalytic activity with a WO₃ : SnO₂ molar ratio of 1 : 1. Under visible light irradiation, the catalytic production of H₂O₂ by the composite is 30 times more efficient than that by its individual components. The n–n heterojunction formed by the combination of WO₃ and SnO₂ allows for the directional transfer of photogenerated electrons and holes, while SnO₂ promotes the migration of electrons from the bulk to the surface of the catalyst, further enabling the spatial separation of the charge carriers and higher oxygen reduction efficiency of the catalyst. This work provides a new research idea for improving WO₃-based photocatalysts for H₂O₂ production and also presents a new pathway for effective visible light-driven generation of H₂O₂.