title: Photocatalytic removal of soot: unravelling of the reaction mechanism by EPR and in situ FTIR spectroscopy.
abstract: Photocatalytic soot oxidation is studied on P25 TiO(2)  as an important model reaction for self-cleaning processes by means of electron paramagnetic resonance (EPR) and Fourier transform infrared (FTIR) spectroscopy. Contacting of carbon black with P25 leads on the one hand to a reduction of the local dioxygen concentration in the powder. On the other hand, the weakly adsorbed radicals on the carbon particles are likely to act as alternative traps for the photogenerated conduction-band electrons. We find furthermore that the presence of dioxygen and oxygen-related radicals is vital for the photocatalytic soot degradation. The complete oxidation of soot to CO(2)  is evidenced by in situ FTIR spectroscopy, no intermediate CO is detected during the photocatalytic process.
authors.affiliation: Research group DuEL, Department of Bioscience-engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium.
authors.forename: Marianne
authors.initials: M
authors.lastname: Smits
authors.forename: Yun
authors.initials: Y
authors.lastname: Ling
authors.forename: Silvia
authors.initials: S
authors.lastname: Lenaerts
authors.forename: Sabine
authors.initials: S
authors.lastname: Van Doorslaer
mesh_terms: D002244:Carbon / Q000737:chemistry; D002245:Carbon Dioxide / Q000737:chemistry; D002248:Carbon Monoxide / Q000737:chemistry; D002384:Catalysis; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D004583:Electrons; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D055668:Photochemical Processes; D053260:Soot / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods
chemical_list: D053260:Soot; D002245:Carbon Dioxide; D002244:Carbon; D002248:Carbon Monoxide; D010100:Oxygen