The hydrogenolysis of CF2Cl2 (CFC-12) has been studied in the gas phase over Pd (3 wt%)/gamma-Al2O3 Pretreatment of the catalyst with CHF2Cl (HCFC-22) was found to significantly improve the catalytic activity and the catalyst lifetime. The formation of Pd-carbide was observed in the CHF2Cl-treated catalyst, and the presence of the palladium carbide is thought to enhance the selectivity to the CH2F2 and to prevent sintering of palladium. XRD, TEM and XPS were used to characterize he structure and the composition of Pd/Al2O3.