THE HYDROGENATION OF ACETYLENE CATALYZED BY Pd-Ag/α-Al2O3: Ag DEPOSITION DEPENDENCE

Amount of Ag adding as the promoter on the Pd/α-Al2O3 catalyst was studied in acetylene selective hydrogenation. The catalysts were prepared with 0.02wt% Pd and Ag/Pd ratios 0, 2.5, 3.7 and 5.3. Catalysts were characterized by XRD, BET, CO-TPD, and reaction performance. At Ag/Pdratios equal to 0 and 2.5, acetylene conversion was around 60% and ethylene selectivity was around 15%, 75%, respectively. By increasing Ag/Pd ratio equal to 3.7, the worst selectivity was obtained because the alloying of Ag and Pd leads to strong adsorption of intermediate species. By increasing the Ag/Pd ratio of 5.3, the geometric effect of Ag was dominant and less conversion and high selectivity were obtained.

کلیدواژه ها:

selective hydrogenation ، acetylene ، palladium ، alumina ، catalyst ، silver