A new preparation method of bimodal catalyst support and its application in Fischer-Tropsch synthesis

The silica-based supports that contained distinct bimodal structure were prepared by incipient-wetness impregnation of silica or zirconia sols into the large pores of silica gel. The pore-size distributions of the obtained supports proved that two kinds of pores coexisted according to the bimodal structure. For these bimodal supports, the increased specific surface area and decreased pore volume indicated that the particles of silica or zirconia sols had entered the large pores of the silica gel. The obtained supports were applied in liquid-phase Fischer - Tropsch synthesis (FTS) after cobalt had been loaded. The catalytic properties of these catalysts exhibited increased activity and decreased selectivities of CH4 and CO2 due to the spatial promotional effect of the bimodal pore structure and chemical effects of the porous zirconia inside the large pores of the original silica gel.