Molybdena containing catalysts have been the subject of numerous studies due to their potential role in different important reactions such as hydrodesulphurization (HDS), hydrogenation (HYD), oxidative dehydrogenation (ODH), hydrodeoxygenation (HDO), hydrodenitrogenation, hydrometallization, isomerization, epoxidation, partial oxidation of alkanes and alkene metathesis reactions. Stannic oxide thin films are attractive for many applications due to their unique physical properties such as high electrical conductivity, high transparency in the visible part of spectrum, and high reflectivity in the IR region. From what has been conferred for CeO2 in addition to its role as either oxygen storage and release or thermal stabilizer. It has been used either as a promoter or as a support for metal catalysts in many applications since the ability of ceria to donate oxygen to supported metals is also a key feature in catalytic reactions. I hope this book will be useful both to students who have studied catalysis or chemical engineering and to graduates who work in or are interested in the industrial catalysis.