Photoreactions of freons on semiconductor surfaces in the presence of air
- Auburn Univ., AL (United States)
The reactions of trichlorofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12) and 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113) initiated on illuminated semiconductor, were studied in systems containing air. Photoreduction of the freons was observed in aqueous suspensions of TiO{sub 2} particles with formation of halide ions. With formate or acetate ions as hole scavengers the rates of reaction increased in the order: CFC-113 {approximately} CFC-12 < CFC-11. Surprisingly, reduction of the CFC molecules was also detected in solutions containing nitrate ions as hole scavenger; the reaction rates followed the trend: acetate < nitrate < formate. In addition, photoreduction of the freons occurred in the absence of solvent, that is, when the gaseous CFC molecules adsorbed on the surface of illuminated semiconductors. Chloride and fluoride ions were generated in a ratio of 3/1 during the solid-gas reaction of CFC-11, indicating that the radical formed in the initial reduction step of the freon decayed via reactions with oxygen.
- OSTI ID:
- 210340
- Report Number(s):
- CONF-9509139--
- Country of Publication:
- United States
- Language:
- English
Similar Records
Liquid densities of HCFC 225ca, HCFC 225cb, and HCFC 141b
Equilibria of 1,1,2,-trichloro-1,2,2-trifluoroethane on activated carbons