To improve the selectivity performance of CoMoS catalysts applied to the hydrodesulfurization (HDS) of fluid catalytic cracking (FCC) gasoline, a series of CoMoS/Al2O3 catalysts was prepared with alumina of different pore structures, and their HDS performance was evaluated with a real FCC gasoline. This study indicated that CoMoS/Al2O3 catalysts prepared with micro-or meso-porous alumina possessed high HDS activity but low selectivity, whereas macro-porous alumina enhanced the selectivity of CoMoS catalysts. The enhanced HDS selectivity was due to the tuning of the MoS2 slabs and the weakening of the internal diffusion resistance. Based on the above results, the optimal CoMoS/Al2O3 catalyst was prepared with the alumina of the tri-modal pore distribution at approximately 5-8 nm, 15-20 nm, and 90-100 nm. The optimal catalyst displayed a balanced HDS activity and selectivity in contrast to the reference catalyst prepared with K- and P-modified Al2O3. (c) 2015 Elsevier Ltd. All rights reserved.