Solar photocatalytic degradation of dyes: high activity of combustion synthesized nano TiO2

The solar photocatalytic degradation of various dyes such as methylene blue (MB), remazol brill blue R (RBBR) and orange G (OG) has been studied over combustion synthesized nano TiO2 and the activity was compared with that of commercial Degussa P-25 TiO2 under similar conditions. The effect of catalyst loading, initial concentrations of the dyes and the deactivation studies of the catalysts were also investigated. The catalyst was characterized by techniques like X-ray diffraction (XRD), BET, gravimetric-differential thermal analysis (TG-DTA), IR and UV absorption. The initial degradation rates with combustion synthesized nano TiO2 was 20 times higher for RBBR, 4 times higher for MB and 1.6 times higher for OG, compared to Degussa P-25 TiO2. The enhanced photocatalytic activity of combustion synthesized catalyst is attributed to the crystallinity, nano-size, large amount of surface hydroxyl species and reduced band-gap.