Solar-assisted photocatalytic reduction of methyl orange azo dye over porous TiO2 nanostructures

Mixed anatase-rutile and pure anatase mesoporous TiO2 photocatalysts have been synthesized for the first time via a modified greener sol-gel approach at low temperature without the involvement of any acid or base. Non-ionic surfactant Brij-35 was used as a sacrificial agent for the synthesis. The effect of additives like dextran and silica nanoparticles on different physical parameters of catalysts was also studied. The chemical, electronic and physical properties of the as-synthesized catalysts were studied by FTIR, TGA, PXRD, DRS, SEM, EDAX, TEM, and BET techniques and the photocatalytic potentiality was also tested by photocatalytic degradation of methyl orange (MO) azo dye. The photocatalytic activity of the synthesized catalysts was found to be in the order TiO2/Brij-35/Si-NPs > TiO2/Brij-35 > TiO2/Brij-35/dextran. The higher photocatalytic activity of TiO2/Brij-35/Si-NPs provided direct evidence of the surface area-dependent photocatalytic activity. As a comparative study, the catalysts were also tested for other environmentally harmful dyes like Rhodamine B and Congo Red and were proven to be highly efficient catalysts for the photodegradation of these dyes.