Catalytic decomposition of CCl2F2 was studied over a number of single and complex metal oxides using a fixed-bed reactor. The ZrO2-Cr2O3 catalyst exhibited the highest activity and CO2 and CClF3 were formed at 350 450°C. Selective decomposition of CCl2F2 into CO2 required the presence of both oxygen and water vapor over the catalyst. Catalytic activity gradually declined with time on stream because of the fluorination of ZrO2. Treatment of the catalyst with both oxygen and water vapor promoted the removal of fluoride ions in sub-surface layers of the catalyst, which is effective for the recovery of the activity. CCl2F2 was decomposed at 300-450°C over AlPO4. No fluorination of the AlPO4 catalyst took place after the reaction for 1000 h. CH2FCF3, an alternative CFC, was completely decomposed over the mixed catalyst of Ce promoted AlPO4 and Cr2O3 at 400-500°C. Catalytic decomposition is a rational method for destruction of used CFCs.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry