Products selectivity and reaction stability of cobalt-based Fischer-Tropsch catalysts affected by glow discharge plasma treatment and silica structure

Abstract

Abstract Fischer-Tropsch performance was evaluated on 15% Co 0.5% Pt based catalysts supported on amorphous SiO2 and SBA-15, and the cobalt precursors were decomposed either by thermal calcination or glow discharge plasma. Plasma assisted decomposition could remarkably improve the dispersion of cobalt species, not only diminished the particle size but also led cobalt crystallites much more homogeneously dispersed; meanwhile, surface acidity was improved and all in the form of Lewis acid sites. The ordered structure of SBA-15 could confine the cobalt particles inside its pore channels, against the occurence of sintering, and the promotion of platinum could maintain the reducibility of cobalt species at relatively high level, even for the plasma treated catalysts with much smaller cobalt particles. As a result, the plasma treated CoPt/SBA-15-P catalyst combined the effects aroused by both plasma treatment and ordered structure of support, showed a best FTS performance among the four investigated samples, including high activity, a highest C5-12 selectivity and a best reaction stability.