To remove sulfur-containing molecules from gasoline via hydrodesulfurization (HDS) while minimizing olefin hydrogenation is quite difficult. In this work, we report that an unsupported Co-Mo catalyst can achieve high HDS activity with low activity in olefin hydrogenation. The HDS selectivity of the Co-Mo catalyst is fourfold that of CoMo/gamma-Al2O3 for both model gasoline and full-range FCC gasoline. For Co-Mo sulfide catalysts, we found that the MoS2 slab morphologies such as curvature, stacking number and slab length were important factors influencing the catalytic performance. Co-Mo catalyst with longer slab length and higher stacking number of MoS2 exhibited higher HDS selectivity. Nevertheless, it was found that the slab length showed much more influence on HDS selectivity than the stacking number. Furthermore, the curved MoS2 could facilitate the olefin isomerization. Present work provides a new way to develop a highly selective HDS catalyst by controlling the MoS2 morphology. (C) 2017 Elsevier B.V. All rights reserved.