Commercial TiO2 (Degussa P25) has attracted a great deal of interest and has been regarded as the most efficient photocatalyst in recent years. In most studies, it is believed that its unique mixed phase (75% anatase and 25% rutile) contributes to the high photocatalytic activity. However, its low efficiency in visible light and nonporous nature cannot be neglected. Here, we report novel mixed phase TiO2 materials with crystallinity, thermal stability (up to 800°C) and mesopore structure. Moreover, their anatase/rutile phase compositions (0-100%) are tunable by controlling of the concentration of framework vanadium dopant and various applied heat treatments. Vanadium (0% to 10% doping) effectively decreased the anatase-rutile transformation temperature (from 1000oC to 600oC) and remarkably enhanced absorption band in visible region (narrowed the band gap). Simultaneously, the mesopore structure was preserved in phase transition process. These mixed phase materials are members of the recently discovered University of Connecticut (UCT) mesoporous materials family, which rely on controlling the sol-gel chemistry of inorganic sols in inverse surfactant micelles and NOx (nitric oxides) chemistry. The mechanisms are randomly packed nano-particle aggregates and mesopores that are formed by connected intraparticle voids. The visible light (&gt; 400 nm) photocatalytic activities of mixed phase mesoporous titania samples were studied by methylene blue (MB), phenol and 4-chlorophenol degradation. The highest photocatalytic activity was obtained by mesoporous titania with 61% anatase and 39% rutile composition. The catalyst can totally remove (100% conversion) methylene blue dye (MB) under visible light irradiation in 2 h, whereas commercial P25 was only able to remove 28 % under the same reaction conditions.

Thermally stable, crystalline, mixed phase (anatase/rutile) mesoporous titanium dioxide as excellent catalyst for photocatalytic organic pollutants degradation

249th National Meeting (2015)

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