Synthesis and optimization of BiVO4 and co-catalyzed BiVO4 nanofibers for visible light-activated photocatalytic degradation of aquatic micropollutants

Abstract

Due to the limited photoefficeincy of TiO2 under solar irradiation, non-titania semiconductors, such as bismuth vanadate (BiVO4), have been gaining attention for use as visible light (VL) photocatalysts. In this work, electrospun BiVO4 nanofibers were synthesized as photocatalysts for VL-induced photo-oxidation of organic pollutants. BiVO4 nanofibers with varied average diameters (33-71 nm) were characterized to observe morphological, dimensional and optical properties and tested in aqueous solutions containing a model pollutant to analyze their photocatalytic activity under solar and VL irradiation conditions. Based on phenol degradation studies at pH 7, k(obs), of the BiVO4 nanofibers increased with decreasing diameter, with the 33 nm sized nanofibers slightly outperforming TiO2 nanomaterials under VL irradiation. Additionally, Ag and Au co-catalyzed BiVO4 nanofibers were developed, showing greater photocatalytic performance. Ag-BiVO4 showed enhancement due to increased carrier traps, where as Au-BiVO4 showed enhancement due to both carrier traps and surface plasmon resonance. Both co-catalyzed BiVO4 nanofibers strongly outperformed TiO2 nanomaterials under VL irradiation, with the greatest enhancement coming from 2 at.% Au-BiVO4. Electrospun BiVO4 nanofibers have the potential to become efficient VL-activated photocatalysts as a low-energy alternative to TiO2 for the removal of emerging organic contaminants. (C) 2015 Elsevier B.V. All rights reserved.