Sulfated and non-sulfated TiO 2-ZrO 2 were promoted with platinum and the activity and selectivity of the resulting catalysts for the hydrolytic decomposition chlorodifluoromethane in air was investigated. The addition of platinum reduced the specific surface area of the catalyst slightly and lowered the catalytic activity. On the other hand, the selectivity of the catalysts towards CO 2 formation was much improved. Metallic platinum was formed by the reduction of the platinum precursor with carbon monoxide produced during the hydrolysis of chlorodifluoromethane over the acidic mixed oxide and promoted the oxidation of CO. At the same time, platinum suppressed completely the formation of the fluorinated byproduct CHF 3, possibly by anchoring itself on the active sites responsible for the fluorination reaction. The platinum promoted non-sulfated TiO 2-ZrO 2 was stable and gave more than 90% of CHClF 2 conversion and 95% selectivity to CO 2 for over 60 h.
Scopus Subject Areas
- Environmental Science(all)
- Process Chemistry and Technology
- Hydrochlorofluorocarbon destruction
- Platinum catalysts