Photocatalytic Oxidation of Diethyl Sulfide Vapor over TiO(2)-Based Composite Photocatalysts

Composite TiO(2)/activated carbon (TiO(2)/AC) and TiO(2)/SiO(2) photocatalysts with TiO(2) contents in the 10 to 80 wt. % range were synthesized by the TiOSO(4) thermal hydrolysis method and characterized by AES, BET, X-ray diffraction and FT-IR ATR methods. All TiO(2) samples were in the anatase form, with a primary crystallite size of about 11 nm. The photocatalytic activities of the TiO(2)/AC and TiO(2)/SiO(2) samples were tested in the gas-phase photocatalytic oxidation (PCO) reaction of diethyl sulfide (DES) vapor in a static reactor by the FT-IR in situ method. Acetaldehyde, formic acid, ethylene and SO(2) were registered as the intermediate products which finally were completely oxidized to the final oxidation products – H(2)O, CO(2), CO and SO(4)(2−) ions. The influence of the support on the kinetics of DES PCO and on the TiO(2)/AC and TiO(2)/SiO(2) samples’ stability during three long-term DES PCO cycles was investigated. The highest PCO rate was observed for TiO(2)/SiO(2) photocatalysts. To evaluate the activity of photocatalysts the turnover frequency values (TOF) were calculated for three photocatalysts (TiO(2), TiO(2)/AC and TiO(2)/SiO(2)) for the same amount of mineralized DES. It was demonstrated that the TOF value for composite TiO(2)/SiO(2) photocatalysts was 3.5 times higher than for pure TiO(2).