Synthesis of one-dimensional WO3–Bi2WO6 heterojunctions with enhanced photocatalytic activity

Abstract

WO₃–Bi₂WO₆ heterostructures were synthesized by a facile hydrothermal method using WO₃ nanorods and Bi(NO₃)₃ solution as raw materials. The Bi₂WO₆ nanosheets uniformly anchored onto the surface of the WO₃ nanorods. The photocatalytic activity of the samples was assessed for degradation of rhodamine B (RhB) and phenol under solar light irradiation. The WO₃–Bi₂WO₆ heterostructures showed higher photocatalytic activities than pure WO₃ and Bi₂WO₆. As the content of Bi₂WO₆ increased, the photocatalytic activity of the WO₃–Bi₂WO₆ heterojunction was enhanced and the optimal sample was WO₃–Bi₂WO₆ with a nWO₃ : nBi³⁺ mole ratio of 5 : 3. The efficient separation of electron–hole pairs because of the staggered band potentials between WO₃ and Bi₂WO₆ may account for the higher photoactivity of WO₃–Bi₂WO₆ hybrid structures. Radical scavenger experiments indicate that holes (h⁺) and superoxide radicals (˙O₂⁻) were the main active species for RhB degradation during the photocatalytic process.