Activation and Catalytic Behavior of Several Co/SiO2 Catalysts for Fischer−Tropsch Synthesis

Abstract

Co(A+N)/SiO2, Co(N)/SiO2, and Co(A)/SiO2 catalysts prepared by impregnation method with a mixture of cobalt nitrate and cobalt acetate (1:1), cobalt nitrate ,and cobalt acetate as precursors, respectively, were reduced by H2 at 300−700 °C and used for FT synthesis from syngas. For the freshly reduced Co(N)/SiO2, Co(A+N)/SiO2, and Co(A)/SiO2 catalysts, H2 chemisorptions are highest at the reduction temperatures of 300−400 °C, 500 °C, and 600 °C, respectively. For the Co(N)/SiO2 catalyst reduced at 400 °C, Co(A+N)/SiO2 catalyst reduced at 500 °C and Co(A)/SiO2 catalyst reduced at 600 °C, reduction degrees vary as Co(N)/SiO2 > Co(A+N)/SiO2 > Co(A)/SiO2; cobalt dispersions vary as Co(A)/SiO2 > Co(A+N)/SiO2 > Co(N)/SiO2. These results suggest that, when oxidized Co/SiO2 catalysts with various interactions between Co precursor and SiO2 support are reduced at their optimum reduction temperatures, respectively, the catalyst with stronger interactions between cobalt precursor and SiO2 support exhibits higher cobal...