Photocatalytic activity and photoelectric performance enhancement for ZnWO4 by fluorine substitution

The formation of fluorine substitution on ZnWO4 (ZnWO4−xF2x) can be easily attained by a two step process. It could be speculated that oxygen ion was substituted by fluorine ion in the crystal lattice of ZnWO4 on the basis of XPS and IR results. Comparing with ZnWO4, the photocatalytic activity of ZnWO4−xF2x sample almost doubled for degradation of methylene blue under UV irradiation. The enhanced photocatalytic activity should be attributed to higher density of surface hydroxyl groups of ZnWO4−xF2x which induced OH radicals to improve photocatalytic reaction. Additionally, ZnWO4−xF2x possessed higher donor density and efficiency of charge separation to increase the transfer rate of charges to the photocatalyst surface and to promote photocatalytic reaction.

ZnWO4−xF2x presented high photocatalytic activity for the MB degradation. The high activity of ZnWO4−xF2x photocatalyst comes from higher density of surface hydroxyl groups which induced OH radicals to improve photocatalytic reaction, and higher donor density and efficiency of charge separation.Figure optionsDownload high-quality image (142 K)Download as PowerPoint slideHighlights
► The formation of fluorine substitution can be attained by a two step process.
► Comparing with ZnWO4, the activity of ZnWO4−xF2x almost doubled.
► Enhanced activity was attributed to higher density hydroxyl of ZnWO4−xF2x.
► ZnWO4−xF2x possessed higher donor density and efficiency of charge separation.