In the present review of our study, it is shown that the CVD technique using CO(CO)(3)NO provides a novel characterization technique of hydrodesulfurization (HDS) catalysts combined with the catalyst preparation. The resultant CVD or designed catalysts are very appropriate for the determination of the COWS structure and reaction mechanism due to a selective formation of CoMoS. The CVD technique is also very effective to prepare highly active HDS catalysts, since full promotion Of MoS2 particles can be achieved. The CVD technique can be applied to estimate the surface structure of supported Co(Ni)-MoS2 catalysts. In addition, the designed catalysts can be used to understand the nature of the support and additives in terms of the intrinsic activity of CoMoS. Thus the information from the CVD technique is unique and invaluable for the development of highly active HDS catalysts. (C) 2007 Elsevier B.V. All rights reserved.