PREPARATION AND PROPERTIES OF A NANO-TiO2 COMPOSITE PHOTOCATALYST SUPPORTED BY NATURAL QUARTZ

The goal of this paper is to improve the technical level of preparing composite photocatalysts with SiO 2 -supported nano-TiO 2 , expand the selection range of SiO 2 carriers, reduce expenses and understand the influence of SiO 2 crystallization behavior. Natural quartz (Q/SiO 2 ) powder was used as a carrier to prepare a Q/SiO 2 -TiO 2 composite photocatalyst by hydrolyzing a butyl titanate solution and performing high-temperature calcination of the hydrolysate. The performance, morphology, structure and mechanism were tested and characterized. In addition, the as-prepared photocatalyst was compared with other amorphous SiO 2 carrier composite photocatalysts. The results showed that the Q/SiO 2 surface of Q/SiO 2 -TiO 2 contained a uniform load of TiO 2 with a 26.98% proportion. Anatase-type TiO 2 was mainly present, and the size was 5–10 nm. Moreover, Q/SiO 2 and TiO 2 were firmly combined in the form of Si–O–Ti bonds between the interfaces. The degradation rate of Q/SiO 2 -TiO 2 to methyl orange solution was 99.59% under UV irradiation for 60 min, which was equivalent to that of pure nano-TiO 2 . The degradation performance remained stable after four cycles. Compared with other amorphous SiO 2 carriers, Q/SiO 2 exhibited a higher load of TiO 2 . Furthermore, Q/SiO 2 played a more significant role in inhibiting the phase transition of TiO 2 to rutile and improving the photocatalytic performance.