Characteristics and catalytic properties of mixed nano-gamma-alumina based-supported cobalt catalyst during carbon monoxide hydrogenation

Abstract

In the present study, the physicochemical properties of cobalt oxide species dispersed on different micron- and nanoscale mixed alumina-zirconia supports were investigated. The samples were prepared by impregnation of the cobalt precursor onto the various mixed alumina-zirconia supports. After calcinations, the samples were characterized with different techniques. TEM revealed that the size of cobalt oxide species depended on the size of supports used. For pure micron- and nanoscale alumina supports, it was found that the catalyst exhibited the similar activities and selectivity. However, increased activity was observed when the nanoscale zirconia support was used compared with the micronscale one. Considering the mixed alumina-zirconia supports, for the micronscale ones it indicated that the presence of zirconia had no effect on both activity and selectivity during carbon monoxide hydrogenation. However, the presence of the nanoscale zirconia in nanoscale alumina apparently resulted in decreased activities, but somehow increased selectivity to 2-3 atomic carbon products. Differences in activity and selectivity can be attributed to the support interaction and the particle size of cobalt oxide species along with the nature of support itself.