Visible-light induced electron modulation to improve photoactivities of coral-like Bi 2 WO 6 by coupling SnO 2 as a proper energy platform

Abstract It is essential to improve the activity of Bi 2 WO 6 for the photocatalytic 2,4-dichlorophenol (2,4-DCP) degradation by modulating the visible-light excited photogenerated electrons. As for this, Bi 2 WO 6 nanostructures have been synthesized by a mannitol assistant hydrothermal method. It is shown that the temperature-optimized Bi 2 WO 6 exhibits high photocatalytic activity for 2,4-DCP degradation under visible-light irradiation, attributed to the coral-like structure, high crystallinity and large surface area. Interestingly, the photocatalytic activities of coral-like Bi 2 WO 6 could be further improved by coupling ultrafine nanocrystalline SnO 2 . It is confirmed mainly from the steady-state and transient-state surface photovoltage responses and fluorescence spectra related to the formed hydroxyl radical amounts that the coupled SnO 2 is taken as a proper energy platform to accept the visible-light excited high-energy-level photogenerated electrons from Bi 2 WO 6 , consequently enhancing the charge separation and prolonging the charge lifetime. Moreover, the optimized SnO 2 -coupled BWO exhibits higher photocatalytic activity under UV–vis light irradiation than the commercial P25 TiO 2 . This work will provide a new feasible route to prepare highly efficient Bi 2 WO 6 -based photocatalysts for purifying chlorophenol-polluted water environments.