Rungnapa Tongpool and Kongthip Setwong

pp. 201 - 206

Abstract

Sulfur-doped TiO₂ (S-TiO₂) was prepared by heat treating thiourea with three types of TiO₂, including commercial P25, C02 and precipitated TiO₂
 (pTiO₂). High S content (1.7 %) in S-doped pTiO₂ (S-pTiO₂) was achieved using relatively low amount of S precursor (S:Ti atomic ratio = 6%). Incorporation of S in TiO₂ structure was influenced by polarity of an
individual host and sulfur solution. Water can be used to prepare S-doped P25 (S-P25) but ethanol was suitable to prepare S-doped C02 (S-C02). Hydrophilicity of TiO₂ and degraded solution played important role in photocatalytic activity. The doping of S either increased or decreased the photocatalytic activity of TiO₂, depending on the total effects arisen after
doping, including the increase of surface area, the extension of the absorption range, the decrease of hole mobility and the blocking of the active sites by the unknown coating layers on the S-doped particles. In this work, S doping improved only the photocatalytic activity of C02 under the sunlight but lessened the activity of P25 and had no effect on pTiO₂
.