TY - JOUR
T1 - Photocatalytic oxidation of gaseous toluene on anatase TiO2 catalyst
T2 - Mechanistic aspects and FT-IR investigation
AU - Augugliaro, Vincenzo
AU - Coluccia, Salvatore
AU - Loddo, Vittorio
AU - Marchese, Leonardo
AU - Martra, Gianmario
AU - Palmisano, Leonardo
AU - Schiavello, Mario
PY - 1999/1/4
Y1 - 1999/1/4
N2 - Photo-oxidation of toluene has been carried out in gas-solid regime by using polycrystalline anatase TiO2 as the catalyst. The reacting gaseous mixture was toluene, air and water in various molar ratios. A pyrex fixed-bed continuous photoreactor irradiated by a medium pressure Hg lamp was used for performing the photoreactivity experiments. The main oxidation product was benzaldehyde but benzene, benzyl alcohol and traces of benzoic acid, phenol and unidentified compounds were also detected. The molar conversion to benzaldehyde with respect to the initial amount of toluene was ca. 20% in the best experimental conditions. Benzene was produced only as a transient product during the first 3-4 h of irradiation. The dependence of feed composition and flow rate on the toluene fractional conversion was investigated. Selected experiments were performed by using N2 or CO2 instead of air. The presence of oxygen was essential for the occurrence of the photoreaction while water played an important role in order to maintain the catalyst activity. Moreover, a Fourier-transform infrared spectroscopy (FT-IR) investigation was carried out simulating the experimental conditions used during the photoreactivity experiments. The results indicated that toluene is weakly stabilised on the hydrated TiO2 particles by hydrogen-bonding with surface hydroxyl groups, and that it is photo-oxidised to benzaldehyde only in the presence of surface OH groups.
AB - Photo-oxidation of toluene has been carried out in gas-solid regime by using polycrystalline anatase TiO2 as the catalyst. The reacting gaseous mixture was toluene, air and water in various molar ratios. A pyrex fixed-bed continuous photoreactor irradiated by a medium pressure Hg lamp was used for performing the photoreactivity experiments. The main oxidation product was benzaldehyde but benzene, benzyl alcohol and traces of benzoic acid, phenol and unidentified compounds were also detected. The molar conversion to benzaldehyde with respect to the initial amount of toluene was ca. 20% in the best experimental conditions. Benzene was produced only as a transient product during the first 3-4 h of irradiation. The dependence of feed composition and flow rate on the toluene fractional conversion was investigated. Selected experiments were performed by using N2 or CO2 instead of air. The presence of oxygen was essential for the occurrence of the photoreaction while water played an important role in order to maintain the catalyst activity. Moreover, a Fourier-transform infrared spectroscopy (FT-IR) investigation was carried out simulating the experimental conditions used during the photoreactivity experiments. The results indicated that toluene is weakly stabilised on the hydrated TiO2 particles by hydrogen-bonding with surface hydroxyl groups, and that it is photo-oxidised to benzaldehyde only in the presence of surface OH groups.
KW - TiO (anatase) photocatalyst
KW - Toluene Fourier-transform infrared spectroscopy
KW - Toluene photo-oxidation
UR - http://www.scopus.com/inward/record.url?scp=0033521511&partnerID=8YFLogxK
U2 - 10.1016/S0926-3373(98)00088-5
DO - 10.1016/S0926-3373(98)00088-5
M3 - Article
SN - 0926-3373
VL - 20
SP - 15
EP - 27
JO - Applied Catalysis B: Environmental
JF - Applied Catalysis B: Environmental
IS - 1
ER -