Effect of nanocrystalline χ-Al2O3 structure on the catalytic behavior of Co/Al2O3 in CO hydrogenation

In the present study, nanocrystalline χ-Al2O3 were prepared by thermal decomposition of fine gibbsite (χ-GB) and solvothermal method (χ-SV) and employed as supports for preparation of 20 wt% Co/Al2O3 catalysts. As compared to the use of γ-Al2O3 with similar BET surface area, Co dispersion and CO hydrogenation activity were higher on the nanocrystalline χ-Al2O3 supported Co catalysts. The transmission electron microscopy (TEM) results revealed that the wrinkled sheets-like structure of γ-Al2O3 was completely destroyed after CO hydrogenation for 6 h whereas the spherical particles of χ-SV and plate-like structure of χ-GB were maintained. The H2-temperature program reduction (H2-TPR) also revealed a stronger interaction between cobalt and alumina supports for the Co/χ-Al2O3 catalysts.