Promoting effect of SiOx monolayer coverage of TiO2 on the photoinduced oxidation of cationic surfactants

摘要: The effect of SiO x monolayer coverage on the rate TiO 2 photoinduced oxidation cetylpyridinium bromide (CPB) in aqueous solutions has been studied. reaction increased ca. 3.4-fold with surface modification 5-6 pH range. promoting was emphasized as initial concentration CPB decreased. Adsorption experiments showed that adsorption strength for (β/M -1 ) increases from 3.7 10 3 (TiO to 2.25 4 (SiO /TiO ), while saturated amount (Γ g /mol m -2 is not so varied 8 ∼ -6 ). A drastic change point zero charge 7.5 3.2 which near value , observed titration experiments. modified Langmuir-Hinshelwood model, where assumed be proportional at photostationary state determined by balance between and decomposition, proposed dilute systems. As result kinetic analyses, enhancement could mainly attributed increase electrostatic attraction ion (increase β).