Abstract: The photocatalytic oxidation of toluene over TiO₂/SiO₂ in the gas-phase was investigated. The feasibility studies involved the effects of initial concentration of reactant, oxygen content, water vapor content and light intensity on the photocatalytic reaction. The photocatalytic degradation rate increased with increasing the initial concentration of toluene, butmaintained almost a constant beyond a certain concentration of it. It matched well with the Langmuir-Hinshelwood kinetic model. The reaction rate increased with increasing oxygen content, but the oxygen content was higher than 18%(volume percentage), the reaction rate was restrained. For the influence of water vapor in the gas-phase on the photocatalytic degradation rate of toluene, there was an optimum concentration of water vapor (0.2%). The photocatalytic degradation rate increased with light intensity but the rate leveled off to a constant when the light intensity rose to 3 mW/cm². The photocatalytic degradation rate constant and the adsorption constant of toluene were obtained by means of the Langmuir-Hinshelwood model, and the reaction products were also identified by FI-RT and GC-MS.

Key words: toluene, photocatalytic, kinetic, nanoparticle