title: Origin of photocatalytic activity in continuous gas phase CO(2) reduction over Pt/TiO(2).
abstract: The dynamic nature of continuous photocatalytic reduction of gaseous CO2 in the presence of water vapor was studied by using Pt/TiO2 as catalyst under UV irradiation at 353 and 423 K in the absence of sacrificial electron donors. The reaction was studied with a good time resolution (order of seconds), to monitor product concentrations by means of mass spectrometry. Two distinct photocatalytic activities, namely steady-state and transient, were identified. The former is active at the lower temperature and only for H2 production, whereas the latter dominates for CH4 production. The transient activity was recovered during dark time (i.e., the light is off) in the reaction mixture, with the magnitude of recovery proportionally increasing with the duration of the dark time. Higher temperature was found to be more effective for the recovery. Furthermore, insights into deactivation and reactivation mechanisms are explained by in situ diffuse reflectance infrared Fourier transform spectroscopy study.
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ), Av. Països Catalans 16, 43007 Tarragona (Spain), Fax: (+34) 977-920-224.
authors.forename: Antonio
authors.initials: A
authors.lastname: Bazzo
authors.forename: Atsushi
authors.initials: A
authors.lastname: Urakawa
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D002384:Catalysis; D003624:Darkness; D004579:Electron Transport; D055668:Photochemical Processes; D010984:Platinum / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: D002245:Carbon Dioxide; C009495:titanium dioxide; D010984:Platinum; D014025:Titanium
keywords: carbon dioxide; ir spectroscopy; photochemistry; titanium dioxide; water splitting