DECOMPOSITION OF CHLOROFLUOROCARBONS ON W TIO2-ZRO2/

The decomposition of chlorofluorocarbons (CFCs) in the presence of wat er vapor was examined over a variety of metal oxides supported on the TiO2-ZrO2 (TZ) catalysts. The tungsten oxide loaded on the TiO2-ZrO2 ( W/TZ) was found to have the highest activity and longest life among th e catalysts examined. The activity of the W/TZ catalysts depended upon the W amount loaded, and it exhibited the highest activity at 1.5 wt% of the loaded tungsten. However, the decomposition of CFC113 over the W/TZ produced undesirable product CO in an amount equimolar to CO2. I t was found that the Pd/TZ was active to oxidize CO into CO2. The cata lyst which was prepared by mechanical mixing of Pd/TZ and W/TZ thus de composed the CFC113 to produce CO2 selectively. Furthermore, its activ ity was not deactivated after 150 h of time on stream. (C) 1997 Elsevi er Science B.V.