Tunable and sustainable photocatalytic activity of photochromic Y-WO3 under visible light irradiation

Abstract

Although photochromic and photocatalytic performance are the most significant features of WO₃, the effects of photochromism on photocatalytic activities have not been investigated further. Herein, a novel gear-shaped WO₃, with high coloration efficiency, fast reversibility, and remarkable photocatalytic performance was successfully prepared via a facile hydrothermal method. The influence of photochromic effects on its photocatalytic properties was evaluated under visible light irradiation. The results showed that the yellow WO₃ sample exhibited higher photocatalytic efficiencies toward tetracycline hydrochloride (TCH), oxytetracycline (OTC), rhodamine B (RhB), and ciprofloxacin (CIP) (94.3%, 87.9%, 76%, and 68.6%, respectively, in 60 min). Further research found that the redox conversion between W⁶⁺ and W⁵⁺ played a key role in separating e⁻/h⁺ pairs. Importantly, the rapid and reversible conversion between W⁶⁺ and W⁵⁺ could be realized through light radiation or H₂O₂ treatment. Therefore, the gear-shaped WO₃ possessed tunable and sustainable photocatalytic properties and maintained a high level of activity after recycling ten times under visible light irradiation. This work provides new insights into practical WO₃ applications for environmental remediation based on photochromic regulation.