Efficient Visible Light Degradation of Rhodamine B by a Photo-Electrochemical Process Based on a Bi2WO6 Nanoplate Film Electrode

Abstract

In this paper, a Bi2WO6 nanoplate film electrode was prepared by a hydrothermal method, combined with a spin coating technique. A photoelectrochemical (PEC) oxidation system based on this electrode was then constructed to degrade rhodamine B (RhB) in aqueous solution under visible light (λ > 420 nm). The PEC system based on Bi2WO6 nanoplate film electrode could degrade 87.2% of RhB with concentration of 5 mg/L in 120 min, operated at low voltage and under visible light irradiation, whereas only 36.8% and 39.5% degradation of RhB were observed for electro-oxidation process (EC) and photocatalytic oxidation process (PC), respectively, operated under the same condition. These results revealed a significant synergetic effect on degrading RhB via electro-oxidation and photocatalysis under visible light irradiation. A possible mechanism for this synergetic degradation of RhB was proposed on the basis of characterization results. Meanwhile, the degradation pathway of RhB during PEC under visible light irradiatio...