6533b871fe1ef96bd12d0e7b

RESEARCH PRODUCT

Comparison of the Photoelectronic and Photocatalytic Activities of Various Anatase and Rutile Forms of Titania in Pure Liquid Organic Phases and in Aqueous Solutions

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Various titania samples of industrial origin (Degussa and Tioxide) have been characterized by electrical photoconductance measurements and tested as photocatalysts in various liquid media (either pure organic liquids or aqueous solutions) as a function of their structure (anatase versus rutile). Anatase was constantly found more active than rutile, whatever the reaction chosen (mild oxidation of pure cyclohexane and 2-propanol; total degradation of phenol and nitrophenol isomers in water). In identical conditions, Degussa was found more active, but the intrinsic activity, expressed in moles converted per hour and per square meter of active surface, was found slightly higher for anatase Tioxide. The higher activity of anatase with respect to that of rutile could be explained by the interpretation of the photoconductance measurements, which evidence the higher aptitude of anatase (i) to photoadsorb oxygen, in O2- and O- forms; (ii) to photodesorb it; and (iii) to have a lower relative electron−hole recombin...