Selective Catalytic Hydrodechlorination of 1,2-Dichloroethane to Ethylene over Ni–Rh Nanoparticle Catalysts Supported on γ-Al₂O₃

Abstract

Ni catalysts decorated with trace Rh supported on γ-Al 2 O 3 were prepared by the co-impregnation method. To obtain the Ni−Rh nanoparticles with different nanostructures and chemical compositions, bimetallic catalysts with varied Ni/Rh molar ratios were prepared. For comparison, monometallic Ni/γ-Al 2 O 3 and Rh/γ-Al 2 O 3 catalysts were also prepared by the impregnation method. The selective gas phase catalytic hydrodechlorination of 1,2-dichloroethane to ethylene was used to evaluate catalytic performances of the catalysts. The catalysts were characterized by X-ray diffraction, N 2 adsorption, X-ray photoelectron spectroscopy, H 2 temperatureprogrammed reduction, transmission electron microscopy−energy-dispersive X-ray, and CO chemisorption. It was found that the introduction of Rh to Ni catalyst facilitated the generation of spillover hydrogen which could enhance the ability of the Ni catalyst for H 2 activation. In bimetallic catalysts, there was an intimate interaction between Ni and Rh, and isolated Rh sites were formed due to the dilution effect of Ni. Accordingly, compared with the monometallic Ni catalyst for gas phase catalytic hydrodechlorination of 1,2-dichloroethane, the bimetallic Ni−Rh(800)/γ-Al 2 O 3 catalyst exhibited markedly higher 1,2-dichloroethane conversion (37%) and comparable selectivity to ethylene (95%). The findings in this study indicate that Ni−Rh/γ-Al 2 O 3 with trace Rh can be used as a promising catalyst for highly effective and selective catalytic hydrodechlorination of chlorinated hydrocarbons.