Interaction between nickel and molybdenum in Ni–Mo/Al 2O 3 catalysts: III. : Effect of impregnation strategy

Abstract

Bimetallic 5 wt.% Ni-5 wt.% Mo/Al 2O 3 catalysts prepared by sequential impregnation and coimpregnation were tested for their physical properties, activity, and selectivity characteristics in CO x hydrogenation at 523–598 K using different feed compositions. Experimental results show that the coimpregnated Ni–Mo catalyst has the highest active metal surface area. Specific activities and activation energies for CO 2 methanation on coimpregnated and sequentially impregnated catalysts indicate that the nature of the synergetic interaction is not affected by the impregnation sequence. CO hydrogenation at relatively high C/H ratios and temperatures above 548 K is accompanied by activity losses on all samples due to carbon deposition. Although there is no significant relation between carbon deposition and C 2–C 4 selectivities, a positive effect on olefin to paraffin ratios is observed at intermediate temperatures.