Visible light-induced degradation of carbon tetrachloride on dye-sensitized TiO2

Citation
Ym. Cho et al., Visible light-induced degradation of carbon tetrachloride on dye-sensitized TiO2, ENV SCI TEC, 35(5), 2001, pp. 966-970
Citations number
36
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Environment/Ecology,"Environmental Engineering & Energy
Journal title
ENVIRONMENTAL SCIENCE & TECHNOLOGY
ISSN journal
0013-936X → ACNP
Volume
35
Issue
5
Year of publication
2001
Pages
966 - 970
Database
ISI
SICI code
0013-936X(20010301)35:5<966:VLDOCT>2.0.ZU;2-Y
Abstract
This study investigated an application of TiO2 photocatalyst sensitized wit h tris(4,4'-dicarboxy-2,2'-bipyridyl)ruthenium(II) complex to CCl4 degradat ion under visible light;irradiation, By injecting electrons from the photoe xcited:sensitizer to the conduction band, the sensitized TiO2 degraded CCl4 under the irradiation of lambda > 420 nm. The quantum yield of CCl4 dechlo rination was about 10(-3). The dechlorination rate of CCl4 was reduced in t he presence of dissolved O-2 due to its competition for conduction band ele ctrons. The photolysis rate was dependent on pH due to the strong pH depend ence of the sensitizer adsorption on TiO2 surface with a maximum degradatio n rate achieved at pH similar to3. A two-site Langmurian model successfully described the adsorption of the sensitizer on TiO2 particles. The monolaye r coverage was achieved at the added sensitizer concentration of 10 muM at [TiO2] = 0.5 g/L. However, the photolysis rate of CCl4 showed a maximum at a sensitizer surface coverage of 0.3 monolayer. Since the photoinduced elec tron injection gradually depleted active sensitizer molecules an TiO2, sacr ificial electron donors to regenerate the sensitizer were sought. 2-Propano l as an electron donor was efficient in the present (RuL3)-L-II/TiO2/CCl4 s ystem, which showed no sign of deceleration in the dechlorination rate up t o 6 h of irradiation.