Differences in characteristics and catalytic properties of Co catalysts supported on micron- and nano-sized zirconia

Nanocrystalline zirconia was prepared by decomposition of zirconium tetra n-propoxide in 1,4-butanediol and was employed as a support for cobalt catalysts. The activity and the selectivity of the catalysts in CO hydrogenation were compared with cobalt supported on commercial available micron- and nano-sized zirconia. The catalytic activities were found to be in the order: Co/ZrO2-nano-glycol ≫ Co/ZrO2-nano-com > Co/ZrO2-micron-com. Compared to the micron-sized zirconia supported one, the use of commercial nano-sized zirconia resulted in higher CO hydrogenation activity but lower selectivity for longer chain hydrocarbons (C4–C6), whereas the use of glycothermal-derived nanocrystalline zirconia exhibited both higher activity and selectivity for C4–C6. The better performance of the latter catalyst can be ascribed to not only the effect of the crystallite size but also the presence of pure tetragonal phase of zirconia.