Chlorodifluoromethane Hydrodechlorination on Carbon-Supported Pd-Pt Catalysts. Beneficial Effect of Catalyst Oxidation

Previously tested 2 wt % palladium-platinum catalysts supported on Norit activated carbon preheated to 1600 °C have been reinvestigated in CHFCl2 hydrodechlorination. An additionally adopted catalyst oxidation at 350–400 produced nearly an order of magnitude increase the turnover frequency Pd/C, from 4.1 × 10−4 2.63 10−3 s−1. This is not caused by changes metal dispersion or possible decontamination Pd surface superficial carbon, but rather unlocking active surface, originally inaccessible particles tightly packed pores carbon. Burning pore walls attached structure, providing easier access for reactants entire palladium surface. Calcination Pt/C and Pd-Pt/C results much smaller evolution catalytic activity than that observed Pd/C. shapes relationship between (TOF) alloy composition, which now does confirm Pd-Pt synergy invoked previous work. The absence this confirmed gradual regular product selectivity, 70 80% towards CH2F2 Pd/C almost 60% CH4 Pt/C. use even higher-preheated (1800 °C), completely free micropores, a need be oxidized achieve high excellent selectivity (>90%).