Photocatalytic activity of V5+, Mo6+ and Th4+ doped polycrystalline TiO2 for the degradation of chlorpyrifos under UV/solar light

✍ Scribed by L. Gomathi Devi; B. Narasimha Murthy; S. Girish Kumar

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 566 KB
• Volume: 308
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/j.molcata.2009.04.007

✦ Synopsis

TiO 2 photocatalysts were prepared by doping transition metal ions like V 5+ , Mo 6+ and an inner transition metal Th 4+ in the concentration range of 0.02-0.1% and were characterized by various analytical techniques. The photocatalytic activities of these catalysts were studied for the mineralization of chlorpyrifos (CP) as a probe molecule. X-ray diffraction results showed only anatase phase irrespective of nature, oxidation state and concentration of these dopants. The photocatalytic activity of undoped TiO 2 showed a better activity under UV light compared to doped catalysts. Under solar light illumination, the Th 4+ (0.06%)-TiO 2 showed highest activity for the mineralization of CP. This was attributed to the prolonged separation of photogenerated electron-hole pairs, high specific surface area of the catalyst and high concentration of surface adsorbed water/hydroxyl groups. Further large shift in the absorption band (460 and 482 nm) due to the creation of mid band gap states by Th 4+ dopant and also by its small crystallite size additionally contributes to the enhancement of the degradation process. The degradation pathway was followed by UV-vis spectroscopic and GC-MS analysis.