Photocatalytic decomposition of phenol over N-TiO_2-SiO_2 catalyst under natural sunlight

摘要

Gel-derived TiO_2-SiO_2 and N-TiO_2-SiO_2 mixed oxides with the TiO_2 : SiO_2 weight ratio of 95 : 5 are synthesised and employed for phenol removal under UVA light and natural sunlight in this study. Both SiO_2 and N are interestingly found to improve the specific surface area of resulting catalysts up to 169m2 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 TiO_2-SiO_2 mixed oxide is found to give rise to the superior photoactivity of TiO_2-SiO_2 catalyst in comparison with TiO_2 counterpart. Under natural sunlight in Hochiminh City on October 2007, N-TiO_2-SiO_2 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 TiO_2-SiO_2 and bare TiO_2, respectively.