Photocatalytic activity of mesoporous WO3/TiO2 nanocomposites for the photodegradation of methylene blue

Abstract

The mesoporous WO3/TiO2 photocatalysts with different loadings of WO3 (5, 10 and 15) wt% were used to remove methylene blue (MB) from aqueous solution. The prepared photocatalysts were characterized by XRD, FTIR, BET, SEM and EDX analysis. The XRD showed that the samples 10 and 15 wt% WO3/TiO2 have signals of anatase and rutile phases of TiO2. FTIR results showed that more hydroxyl groups bind onto the surface of the sample 10 wt% WO3/TiO2 which enhances the photodegradation as they yield OH. The ultraviolet visible diffuse reflection spectra (DRS) indicated that the addition of WO3 to TiO2 decrease the band gap energy from 3.11 to 2.92 eV. The photocatalytic measurements showed that the addition of WO3 to the surface of TiO2 increased the photodegradation of MB to 99% after 3 h on the sample 10 wt% WO3/TiO2. Further addition of WO3 particles agglomerate on TiO2 surface and decrease the photodegradation. The kinetic studies confirmed that the photocatalytic degradation of MB follows the kinetics of the pseudo-first-order model.