In the present study, nanocrystalline chi-Al2O3 were prepared by thermal decomposition of fine gibbsite (chi-GB) and solvothermal method (chi-SV) and employed as supports for preparation of 20 wt% Co/Al2O3 catalysts. As compared to the use of gamma-Al2O3 with similar BET surface area, Co dispersion and CO hydrogenation activity were higher on the nanocrystalline chi-Al2O3 supported Co catalysts. The transmission electron microscopy (TEM) results revealed that the wrinkled sheets-like structure of gamma-Al2O3 was completely destroyed after CO hydrogenation for 6 h whereas the spherical particles of chi-SV and plate-like structure of chi-GB were maintained. The H-2-temperature program reduction (H-2-TPR) also revealed a stronger interaction between cobalt and alumina supports for the Co/chi-Al2O3 catalysts. (C) 2010 Elsevier B. V. All rights reserved.