AgPd catalysts have been synthesized on SiO2, TiO2, and carbon supports using controlled surface reactions to form well defined active site structures. These catalysts were studied for hydrodechlorination of 1,2-dichloroethane to form ethane, ethylene, and chloroethane. The formation of bimetallic AgPd structures is most effective for AgPd/TiO2, followed by AgPd/C and then AgPd/SiO2 catalysts. FTIR spectra of adsorbed CO suggest that Pd is well dispersed on the Ag nanoparticles for the TiO2-supported catalyst, while more contiguous Pd sites are present on the SiO2-supported catalyst. Ethylene selectivities of up to 97% and 82% are achieved on AgPd/TiO2 and AgPd/C catalysts, respectively. The AgPd/SiO2 catalyst is 91% selective to ethane. These results indicate that the well dispersed Pd achieved at low Pd loadings on TiO2 and carbon is selective to ethylene, while the contiguous Pd species formed on SiO2 are selective to ethane. Furthermore, increased reactivity is correlated to high ethylene selectivity. (C) 2018 Elsevier Inc. All rights reserved.