Electron flux at the Schottky junction of Bi NPs and WO3-supported g-C3N4: an efficient ternary S-scheme catalyst for removal of fluoroquinolone-type antibiotics from water.

Abstract

Recently, global-scale attempts have been conducted to develop clean technologies and affordable materials to remediate pharmaceutical contaminants of water resources that are resistant to the biodegradation. In line with global efforts, this study reports a facile method to fabricate Bi nanocrystals in situ decorated on WO3 nanoplates and its composite with graphitic carbon nitride (WO3/Bi/g-C3N4) for photocatalytic degradation of fluoroquinolone-type antibiotics (ciprofloxacin and ofloxacin). The designed ternary S-scheme WO3/Bi/g-C3N4 composite material was fully characterized by physicochemical and electrochemical analysis. Depositing the cost-effective and earth-abundant Bi nanocrystals onto WO3 via a facile reduction route has been shown to increase the boosting of electron flux at their interface (Schottky junction). The S-scheme separation is confirmed by the calculation of band positions and the analysis of photogenerated hydroxyl radicals and holes. The complete removal of contaminants was obtained over the WO3/Bi/g-C3N4 photocatalyst after 90 min under visible light irradiation. The present work would provide a rational route for developing Bi NP-based photocatalysis to replace metallic Au, Pt, and Ag NPs.