Relationship between adsorption properties of Pt–Cu/SiO2 catalysts and their catalytic performance for selective hydrodechlorination of 1,2-dichloroethane to ethylene

Microcalorimetric adsorption technique was employed to study the interaction of the reactants and product in the 1,2-dichloroethane hydrodechlorination over Pt/SiO2, Cu/SiO2 and Pt–Cu/SiO2 catalysts in order to understand the high selectivity towards C2H4 on the Pt/SiO2 catalyst modified by Cu. When the adsorption properties of the reactants and product on bimetallic catalysts were compared with those on monometallic counterparts, significant differences in the strength and number of adsorption sites concerning the reactants and product were evidenced. The adsorption properties of the bimetallic catalysts could be attributed to the change in Pt surface structure modified by Cu, studied by the microcalorimetry and FTIR of CO adsorption. Relating the adsorption properties with high ethylene selectivity on bimetallic catalysts, we inferred that high ethylene selectivity on bimetallic catalysts could be attributed to the moderate adsorption and activation of reactants and product. This work gave the direct evidence of high C2H4 selectivity in 1,2-dichloroethane hydrodechlorination reaction on the Pt–Cu/SiO2 catalysts from the energetic point of view.