Characterization and activity of visible-light driven TiO2 photocatalyst doped with tungsten

摘要

This research aimed to expand the activity of TiO2 down to the visible light region by modifyingnthe sol-gel conditions and doping with tungsten. The optimum conditions for calcinationntemperature, acid type, and heating rate were 2008C, HNO3, and 18C/min, respectively. Thenundoped TiO2 synthesized under these conditions could significantly absorb the visible lightnwhereas the commercial Degussa P-25 could not. The absorptivity decreased sequentially as thenwavelength increased from 400 to 700 nm. Within 6 h of 2-W blue-light illumination, 23% ofn0.1mM 2-chlorophenol was removed. The XRD result showed that the crystalline was anatasenphase. The visible-light absorption property of the TiO2 became even better when doped withntungsten. At the optimum W to TiO2 ratio of 0.5%, the degradation of 0.1mM 2-chlorophenolnincreased to 53% indicating a higher photocatalytic activity. Both crystalline and amorphous TiO2ncould exhibit the photocatalytic activity under the visible light region.