title: Polydopamine-Coated TiO2 Nanotubes for Selective Photocatalytic Oxidation of Benzyl Alcohol to Benzaldehyde Under Visible Light.
abstract: TiO2 nanotube arrays grown by anodization were coated with thin layers of polydopamine as visible light sensitizer. The PDA-coated TiO2 scaffolds were used as photocatalyst for selective oxidation of benzyl alcohol under monochromatic irradiation at 473 nm. Benzaldehyde was selectively formed and no by-products could be detected. A maximized reaction yield was obtained in O2-saturated acetonitrile. A mechanism is proposed that implies firstly the charge carrier generation in polydopamine as a consequence of visible light absorption. Secondly, photo-promoted electrons are injected in TiO2 conduction band, and subsequently transferred to dissolved O2 to form O*2- radicals. These radicals react with benzyl alcohol and lead to its selective dehydrogenation oxidation towards benzaldehyde.
authors.forename: Jyotsna
authors.initials: J
authors.lastname: Tripathy
authors.forename: Gabriel
authors.initials: G
authors.lastname: Loget
authors.forename: Marco
authors.initials: M
authors.lastname: Altomare
authors.forename: Patrik
authors.initials: P
authors.lastname: Schmuki
mesh_terms: D065966:Absorption, Physicochemical; D001547:Benzaldehydes / Q000138:chemical synthesis* / Q000528:radiation effects; D019905:Benzyl Alcohol; D002384:Catalysis / Q000528:radiation effects; D007211:Indoles / Q000737:chemistry* / Q000528:radiation effects; D008027:Light; D008422:Materials Testing; D043942:Nanotubes / Q000737:chemistry* / Q000528:radiation effects* / Q000648:ultrastructure; D010084:Oxidation-Reduction / Q000528:radiation effects; D011108:Polymers / Q000737:chemistry* / Q000528:radiation effects; D011829:Radiation Dosage; D014025:Titanium / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D001547:Benzaldehydes; D007211:Indoles; D011108:Polymers; C568283:polydopamine; C009495:titanium dioxide; D014025:Titanium; D019905:Benzyl Alcohol; C032175:benzaldehyde