Photocatalytic decomposition of phenol over N-TiO2- SiO2 catalyst under natural sunlight

Abstract

Gel-derived TiO2-SiO2 and N-TiO2 -SiO2 mixed oxides with the TiO2:SiO2 weight ratio of 95:5 are synthesised and employed for phenol removal under UVA light and natural sunlight in this study. Both SiO2 and N are interestingly found to improve the specific surface area of resulting catalysts up to 169 m2 g-1. Meanwhile, only N is observed to shift significantly the light absorption of derived catalyst to visible range. Optimisation between specific surface area and crystallinity in TiO2-SiO2 mixed oxide is found to give rise to the superior photoactivity of TiO2 -SiO2 catalyst in comparison with TiO2 counterpart. Under natural sunlight in Hochiminh City on October 2007, N-TiO2-SiO2 presents the outstanding photoactivity towards decomposition of 10 ppm phenol aqueous solution with the efficiency up to 100% as compared to those of 65 and 48% for bare TiO2-SiO2 and bare TiO2, respectively.