Enhancement of acetylene hydrogenation activity over Ni-Zn bimetallic catalyst by doping with Au.

A series of modified Ni-Zn bimetallic catalysts were prepared by depositing different kinds of 4 wt% metals (Ir, Pt, Au, Cu, Ag) on the Ni-Zn-Al hydrotalcite (NZAH) and tested in the selective hydrogenation of acetylene. The activity was enhanced by 3-fold over the 4 wt% Au/NZAH, meanwhile, the yield of C2H4 was also increased more than 4 times compared with the NZAH. Characterization by means of H2-TPR, XRD, SEM, and TEM revealed that Au was highly dispersed on the catalyst, and the ternary Au-Ni-Zn alloy was formed during the H2 reduction at 500 degrees C. Doping Au in Ni-Zn bimetallic catalyst weakens the adsorption of acetylene and also hinders the coke deposition on the catalyst, which leads to the enhanced activity in acetylene hydrogenation.