Effect of sulfur doping on the photocatalytic performance of BiVO4 under visible light illumination

Abstract

Porous monoclinic bismuth vanadate (BiVO 4− δ ) and sulfur-doped bismuth vanadates (BiVO 4− δ S 0.05 , BiVO 4− δ S 0.08 , and BiVO 4− δ S 0.12 ) were synthesized by a dodecylamine-assisted alcohol-hydrothermal route in the absence and presence of thiourea or Na 2 S. The physicochemical properties of the materials were characterized and their photocatalytic performance for the degradation of methylene blue and formaldehyde under visible light was evaluated. The samples have a single phase monoclinic scheetlite crystal structure with a porous olive-like morphology, surface areas of 8.4–12.5 m 2 /g, and bandgap energies of 2.40–2.48 eV. Surface Bi 5+ , Bi 3+ , V 5+ , and V 4+ species were present on the S-doped BiVO 4− δ samples. Sulfur doping influenced the surface Bi 5+ /Bi 3+ , V 5+ /V 4+ , and O ads /O latt molar ratios, and the amount of sulfur doped had an important effect on the photocatalytic performance. Under visible light, BiVO 4− δ S 0.08 performed the best in the photodegradation of methylene blue and formaldehyde. A higher surface oxygen species concentration and a lower bandgap energy were responsible for the excellent visible light photocatalytic performance of BiVO 4− δ S 0.08 . Porous BiVO 4− δ and BiVO 4− δ S σ are fabricated using dodecylamine-assisted alcohol-hydrothermal strategy. The higher O ads concentration and lower bandgap energy account for excellent photocatalytic performance of BiVO 4− δ S 0.08 for methylene blue and formaldehyde degradation.