Photocatalytic degradation of chlorinated propenes using TiO2

The photocatalytic degradation of chlorinated propenes using TiO2 was investigated by FTIR spectroscopy. The chlorinated propenes were degraded to HCl, CO2, CO, H2O, and HCOOH during UV irradiation. During the degradation of 3-chloro-1-propene, the concentrations of CO2, CO, and HCOOH increased just after starting the irradiation. The onset of the HCl formation was delayed. On the other hand, the onset of the HCOOH formation was delayed during the degradation of 1-chloro-1-propene. During the degradation of 2-chloro-1-propene, the rate of the HCOOH production was slower than that during the degradation of 3-chloro-1-propene although the HCl production was not delayed. These results indicated that HCOOH was produced by the degradation of the double-bonded carbon bonding to two H atoms during the initial stage. The chlorinated compounds were preferentially produced from the double-bonded carbon bonding to the Cl atom and rapidly degraded to HCl, CO2, and CO during the initial stage. The residual part was degraded in the latter steps. Furthermore, it is suggested that the Cl atom on one of the double-bonded C atoms of the propenes was transferred to the other C atom before the degradation. Consequently, the double-bonded carbon bonding to two H atoms in 2-chloro-1-propene was chlorinated, then degraded to HCl, CO2, and CO during the initial stage.ArticleRESEARCH ON CHEMICAL INTERMEDIATES. 41(10):7641-7654 (2015)journal articl

Photocatalytic activity of titania layer prepared by oxidizing titanium compounds on titanium plate surface

Anatase-type nanocrystalline titania layers were prepared by oxidizing the crystalline titanium nitride and carbon-doped titanium nitride phases prepared on a titanium plate surface. Identification of the crystalline phase was confirmed by the XRD patterns and Raman spectra of these plates. The photocatalytic activity of the plates was evaluated by observing the photocalytic degradation process of acetaldehyde gas during UV irradiation by gas chromatography. A relatively larger amount of the anatase phase was formed on the very thin surface layer by heating the carbon-doped titanium nitride phase at 500 degrees C, and it exhibited a higher photocatalytic activity for the acetaldehyde degradation. The activity was determined not only by the amount of the anatase phase, but also by the crystallite size depending on the surface area and charge transfer efficiency. The photocatalytic activity is suggested to be due to the anatase phase existing on the thin surface layer accessible to the reactants.ArticleAPPLIED CATALYSIS B-ENVIRONMENTAL. 127:227-233 (2012)journal articl

Photocatalytic activity of titania layer prepared by oxidizing titanium compounds on titanium plate surface

Anatase-type nanocrystalline titania layers were prepared by oxidizing the crystalline titanium nitride and carbon-doped titanium nitride phases prepared on a titanium plate surface. Identification of the crystalline phase was confirmed by the XRD patterns and Raman spectra of these plates. The photocatalytic activity of the plates was evaluated by observing the photocalytic degradation process of acetaldehyde gas during UV irradiation by gas chromatography. A relatively larger amount of the anatase phase was formed on the very thin surface layer by heating the carbon-doped titanium nitride phase at 500 degrees C, and it exhibited a higher photocatalytic activity for the acetaldehyde degradation. The activity was determined not only by the amount of the anatase phase, but also by the crystallite size depending on the surface area and charge transfer efficiency. The photocatalytic activity is suggested to be due to the anatase phase existing on the thin surface layer accessible to the reactants

Photocatalytic degradation of chlorinated ethenes

Degradation of three chlorinated ethenes, trichloroethylene, trans-1,2-dichloroethylene and cis-1,2-dichloroethylene, by UV-light irradiated TiO2 catalyst prepared by the sol-gel method in dry air at ambient temperature have been examined by using FTIR measurement. The chlorinated ethenes rapidly decomposed to produce dichloroacethyl chloride, CO, HCl, and COCL2. For trans- and cis-1,2-DCE systems isomerization to each other is found to be the first step of the degradation. The C = C bond of the chlorinated ethenes interacts directly with TiO2 site and, consequently, the degradation results in several products on the catalyst surface in these systems

Photocatalytic degradation of chlorinated propenes using TiO2

The photocatalytic degradation of chlorinated propenes using TiO2 was investigated by FTIR spectroscopy. The chlorinated propenes were degraded to HCl, CO2, CO, H2O, and HCOOH during UV irradiation. During the degradation of 3-chloro-1-propene, the concentrations of CO2, CO, and HCOOH increased just after starting the irradiation. The onset of the HCl formation was delayed. On the other hand, the onset of the HCOOH formation was delayed during the degradation of 1-chloro-1-propene. During the degradation of 2-chloro-1-propene, the rate of the HCOOH production was slower than that during the degradation of 3-chloro-1-propene although the HCl production was not delayed. These results indicated that HCOOH was produced by the degradation of the double-bonded carbon bonding to two H atoms during the initial stage. The chlorinated compounds were preferentially produced from the double-bonded carbon bonding to the Cl atom and rapidly degraded to HCl, CO2, and CO during the initial stage. The residual part was degraded in the latter steps. Furthermore, it is suggested that the Cl atom on one of the double-bonded C atoms of the propenes was transferred to the other C atom before the degradation. Consequently, the double-bonded carbon bonding to two H atoms in 2-chloro-1-propene was chlorinated, then degraded to HCl, CO2, and CO during the initial stage.ArticleRESEARCH ON CHEMICAL INTERMEDIATES. 41(10):7641-7654 (2015)journal articl