SiOx Monolayer Overcoating Effect on the TiO2 Photocatalytic Oxidation of Cetylpyridinium Bromide

✍ Scribed by Hiroaki Tada; Yasuyuki Kubo; Manabu Akazawa; Seishiro Ito

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 91 KB
• Volume: 221
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1999.6578

✦ Synopsis

The effect of SiO x monolayer coverage on the rate of TiO 2 photocatalytic oxidation of cetylpyridinium bromide (CPB) in aqueous solutions has been studied. The rate of CPB removal from the solution (5 < pH < 7) increases with the surface modification at concentrations below 4.5 × 10 -4 M and its promoting effect is enhanced with decreasing concentration. A modified Langmuir-Hinshelwood model, where the rate of surface reaction is assumed to be proportional to the coverage of CPB at the photostationary state is proposed for dilute reaction systems. As a result of the kinetic analyses, the acceleration of the reaction with the SiO x monolayer coverage can be attributed to the increase in the rate of adsorption due to the electrostatic attraction of cetylpyridinium ion. The suppression of Br -adsorption is also suggested as a minor contribution.