Catalytic decomposition of CFCs

Catalytic decomposition of CCl2F2 was studied over a number of single and c omplex metal oxides using a fixed-bed reactor. The ZrO2-Cr2O3, catalyst exh ibited the highest activity and CO2 and CClF3 were formed at 350-450 degree s C. Selective decomposition of CCl2F2 into CO2 required the presence of bo th oxygen and water vapor over the catalyst. Catalytic activity gradually d eclined with time on stream because of the fluorination of ZrO2. Treatment of the catalyst with both oxygen and water vapor promoted the removal of fl uoride ions in sub-surface layers of the catalyst, which is effective for t he recovery of the activity. CCl2F2 was decomposed at 300-450 degrees C ove r AlPO4. No fluorination of the AlPO4 catalyst took place after the reactio n for 1000 h. CH2FCF3, an alternative CFC, was completely decomposed over t he mixed catalyst of Ce promoted AlPO4 and Cr2O3 at 400-500 degrees C. Cata lytic decomposition is a rational method for destruction of used CFCs.