Selective Hydrogenation of Acetylene to Ethylene over Bimetallic Catalysts

Ni/α-Al2O3 catalyst and a series of bimetallic catalysts including Pd–Ag, Ni–Pd, Ni–Zn, Ni–Ag, and Ni–Ga were synthesized, characterized, and tested in selective hydrogenation of acetylene to ethylene. The bimetallic catalyst Ni–Ga exhibited almost the same ethylene selectivity compared to Pd–Ag based catalyst. The effect of the Ni/Ga ratio on the catalytic activity and selectivity to ethylene in acetylene hydrogenation was evaluated. Characterization by transmission electron microscopy, X-ray diffraction, hydrogen temperature-programmed reduction, and X-ray photoelectron spectroscopy was carried out to identify active phases on Ni–Ga based catalysts, which was correlated with catalytic performance and the reaction mechanism occurring over the catalyst. The presence of Ga in Ni–Ga lattice structure confined the movement of dissociated H* and reduced the adsorption binding energy of ethylene, which could prevent overhydrogenation of acetylene.