Preparation Of S-tio_2 Photocatalyst And Photodegradation Of L-acid Under Visible Light

摘要

S-doped TiO_2 (S-TiO_2) photocatalyst was synthesized by sol-gel method with tetrabutyl titanate and thiourea as precursor. S-TiO_2 was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis absorption spectroscopy, transmission electron microscopy (TEM) and the photocatalytic activity was evaluated by 1-naphthol-5-sulfonic acid (L-acid) under UV, visible light and solar light radiation. The results showed that doped S could improve photoabsorption property of TiO_2 in the visible region, leading the increase in the photocatalytical activity of TiO_2. The average particle size of the S-TiO_2 photocatalyst is about 10 nm. The S-TiO_2-4 photocatalyst contains 100% anatase crystalline phase of TiO_2. In the S-TiO_2-4 photocatalyst, S does not exist independently, but is incorporated into the crystal lattice of TiO_2. In the inner crystal lattice of the S-TiO_2-4 photocatalyst, S as S~(2-) replaces O in TiO_2. while on the surface of crystal lattice, S exists as S~(4+) and S~(6+). The photocatalytical activity of S-TiO_2-4 photocatalyst for the photodegradation of L-acid is better than that of pure TiO_2. Under the same conditions, the photodegradation efficiency of L-acid for the S-TiO_2-4 photocatalyst and the solar light irradiation is 85.1%, while it is only 26.4% for pure TiO_2. In addition, the final products of the photocatalysis of L-acid using the S-TiO_2-4 photocatalyst are not organic compounds with low molecular weight, but the inorganic compounds.