Hollow flower-like WO3@TiO2 heterojunction microspheres for the photocatalytic degradation of rhodamine B and tetracycline†

Abstract

In the context of sustainable development, the utilization of semiconductor materials for the degradation of dyes, antibiotics, heavy metals, and pesticides in wastewater under visible light has emerged as a focal point of contemporary research. In this investigation, a WO₃@TiO₂ composite was synthesized via a solvothermal method, with the composite exhibiting a molar ratio of 5% WO₃ to TiO₂ precursors demonstrating optimal photocatalytic degradation performance. This material achieved complete degradation of 20 mg per L Rhodamine B (RhB) dye and tetracycline (TC) antibiotic within 30 min. Furthermore, the effects of initial pollutant concentration and solution pH on catalytic efficacy were systematically explored. The findings revealed that at RhB concentrations below 40 mg L⁻¹, the degradation proceeded at an accelerated rate, with a rate constant exceeding 0.128 min⁻¹. The catalyst exhibited robust performance across a broad pH range, attaining peak degradation efficiency at pH ≈ 3. The exceptional photocatalytic prowess of the WO₃@TiO₂ composite is predominantly attributable to its distinctive hollow microstructure, the intimate interfacial synergy between WO₃ and TiO₂, and the efficient separation of photogenerated electrons and holes facilitated by the type-II heterojunction architecture.