Photocatalytic performance of TiO2 catalysts modified byH3PW12O40, ZrO2 and CeO2
CAI Tiejun , LIAO Yuchao , PENG Zhenshan , LONG Yunfei , WEI Zongyuan , DENG Qian
DOI:
Received July 19, 2008,Revised November 10, 2008, Accepted , Available online
Volume 21,2009,Pages 997-1004
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The binary composite photo-catalysts CeO2/TiO2, ZrO2/TiO2 and the ternary composite photo-catalysts H3PW12O40-CeO2/TiO2,
H3PW12O40-ZrO2/TiO2 were prepared by sol-gel method. The catalysts were characterized by thermogravimetric-di erential thermal
analysis (TG-DTA), scanning electron microscopy (SEM) and X-ray di raction (XRD). The photocatalytic elimination of methanol
was used as model reaction to evaluate the photocatalytic activity of the composite catalysts under ultraviolet light irradiation. The
e ects of doped content, activation temperature, time, initial concentration of methanol and gas flow rate on the catalytic activity
were investigated. The results showed that after doping a certain amount of CeO2 and ZrO2, crystallization process of TiO2 was
restrained, particles of catalysts are smaller and more uniform. Doping ZrO2 not only significantly improved the catalytic activity, but
also increased thermal stability. Doping H3PW12O40 also enhanced the catalytic activity. The catalytic activities of binary and ternary
composite photocatalysts were significantly higher than un-doped TiO2. The dynamics law of photocatalytic reaction over the binary
CeO2/TiO2 and ZrO2/TiO2 catalysts has been studied. The activation energy 15.627 and 15.631 kJ/mol and pre-exponential factors
0.5176 and 0.9899 s??1 over each corresponding catalyst were obtained. This reaction accords to the first order dynamics law.
