Characterization of palladium supported on γ-Al2O3 catalysts in hydrodechlorination of CCl2F2

Alumina supported palladium catalysts are prepared by wet impregnation technique with varying Pd loading. The reduced catalysts are tested for their activity and selectivity in the hydrogenolysis of CCl2F2 to CH2F2. Modified TPR set-up is used to distinguish between halide reduction and carbon reduction and, based on these results, the reduction mechanism of Pd/Al2O3 catalysts is elucidated for both fresh and spent forms of catalysts. TEM revealed that there is a strong re-dispersion of palladium taking place during the reaction. The palladium loading for maximum conversion of CCl2F2 and yielding for CH2F2 is 8 wt.% Pd on γ-Al2O3. XRD, TEM and TPR results show that Pd particle size has influence on the CCl2F2 hydrogenolysis activity and selectivity to CH2F2 and CH4.