Selective hydrodechlorination of 1,2-dichloroethane to ethylene over Pt-Ag/Al2O3 catalysts prepared by surface redox

摘要

1,2-Diehloroethane is a common air pollutant,and selective catalytic hydrodechlorination to ethylene is an attractive approach to eliminate the pollutant and concomitantly recovers valuable ethylene.In the present study,Al2O3 supported Pd-Ag bimetallic catalysts were prepared by a surface redox method (denoted as sr-Pd-Ag/Al2O3) and by an impregnation method (denoted as im-Pd-Ag/Al2O3),and were further tested for selective catalytic hydrodechlorination of 1,2-dichloroethane.The catalysts were characterized by transition electron microscopy,X-ray diffraction,CO chemisorptions and X-ray photoelectron spectroscopy.Characterization results showed that both the surface redox method and impregnation method could decrease the content of exposed Pd sites.However,more prominent Ag enrichment was identified on sr-Pd-Ag/Al2O3 than on im-Pd-Ag/Al2O3.Additionally,given similar metal contents more effective blocking of exposed Pd sites could be obtained on sr-Pd-Ag/Al2O3 than on im-Pd-Ag/Al2O3.Accordingly,sr-Pd-Ag/Al2O3 displayed much higher ethylene selectivity than im-Pd-Ag/Al2O3.