Mesoporous TiO2 with WO3 functioning as dopant and light-sensitizer: A highly efficient photocatalyst for degradation of organic compound

The suitable doping or modification on TiO 2 holds promise for improving charge separation and extending light absorption range. Here, WO 3 modifying reduced band gap mesoporous TiO 2 (WO 3 /RM-TiO 2 ) due to WO 3 doping was successfully fabricated by immersing mesoporous TiO 2 nanoparticles in the peroxotungstic acid sol with controllable reaction time (0–1 h). The W 6+ ions were first incorporated into the TiO 2 lattice to form W O Ti bonds, resulting in the formation of WO 3 doping TiO 2 . Then, WO 3 nanoparticles gradually formed and attached on the TiO 2 surface, constructing a novel heterojunction catalyst with WO 3 serving as both dopant and light-sensitizer for TiO 2 . Photocatalytic activity of the resulting WO 3 /RM-TiO 2 depends on the immersing duration in the peroxotungstic acid. The BET analysis shows that 0.5 h-WO 3 /RM-TiO 2 has the largest pore volume of 0.491 cm 3  g −1 and the highest surface area of 82.3 m 2  g −1 , whereas these values decline with prolonged immersing duration. As expected, the optimal efficiency in removing p-nitrophenol (PNP) is achieved over 0.5 h-WO 3 /RM-TiO 2 under visible light irradiation, which is 2.33 times that of the unmodified M-TiO 2 . This should be attributed to the suitable WO 3 doping and WO 3 modification.