Effects of Weak Surface Modification on Co/SiO(2) Catalyst for Fischer-Tropsch Reaction

A weak surface modification is applied to Co/SiO(2) catalyst by hydrothermal treatment at 180°C for 5 h. Aluminum is introduced to Co/SiO(2) catalysts during the surface modification. The effects of surface modification on Co/SiO(2) catalyst are studied by changing the operating sequences of surface modification and cobalt impregnation in the catalyst preparation. Surface modification before cobalt impregnation makes Co(3)O(4) particle small and dispersed into the deep part of enlarged pore in SiO(2), while surface modification after cobalt impregnation does not obviously change the particle size of Co(3)O(4). The improved amplitude of catalytic activity is similar for the two kinds of catalysts, but they are benefited from different factors. The content of iso-hydrocarbons in the products is increased by the surface modifications.