Physicochemical properties of cobalt dispersed on mixed nano-silica-based supports

Abstract

In the present study, differences in characteristics and catalytic activity toward CO hydrogenation of Co catalysts dispersed on various micron- and nanoscale mixed SiO₂-ZrO₂ supports were investigated. The various weight ratios of SiO₂/ZrO₂ were prepared by a physical mixing in toluene solution, then consequently impregnated with the cobalt precursor. After calcinations, the various samples were characterized using XRD, SEM/EDX, TEM, TPR and H₂ chemisorption. CO hydrogenation (H₂/CO = 10/1) was also performed to determine the overall activity and selectivity. It revealed that the size of Co oxide species depends on the size of support used. A wide range of variables including particle size, support interaction, and the type of supports can affect the kinetics of reduction. It was found that for the SiO₂ support, the catalyst dispersed on the micronscale was more active due to the strong interaction. In contrast, the catalyst dispersed on the micronscale was more active due to the strong interaction. In contrast, the catalyst dispersed on the nanoscale ZrO₂ was more active due to the weak interaction. It was mentioned that for the mixed SiO₂-ZrO₂, the properties of catalyst were similar with those of the sole SiO₂ support. It was suggested that the strong interaction for SiO₂ was more pronounced.