Interaction between nickel and molybdenum in Ni-Mo/Al2O3 catalysts: III. Effect of impregnation strategy

Bimetallic 5 wt.% Ni-5 wt.% Mo/Al2O3 catalysts prepared by sequential impre gnation and coimpregnation were tested for their physical properties, activ ity, and selectivity characteristics in COx hydrogenation at 523-598 K usin g different feed compositions. Experimental results show that the coimpregn ated Ni-Mo catalyst has the highest active metal surface area. Specific act ivities and activation energies for CO2 methanation on coimpregnated and se quentially 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 selectivit ies, a positive effect on olefin to paraffin ratios is observed at intermed iate temperatures. (C) 1999 Elsevier Science B.V. All rights reserved.