Ceria plays an important role in catalysis, due to its ability to store and release oxygen depending on the condition present in the catalyst environment. To analyze the role of ceria in catalytic reactions it is necessary to know the details of the interaction of ceria surface with environmentally sensitive molecules. This study was conducted using ultra accelerated quantum chemical molecular dynamics UA-QCMD to investigate the reduction processes of the (1 1 1) and (1 1 0) surfaces of ceria with molecular hydrogen as well as water desorption mechanisms from the surfaces. This simulation demonstrated that when high-energy colliding hydrogen's are adsorbed on the ceria, it pulls up an O atom from the ceria surfaces and results in the formation of a H2O molecule. This is the first time quantum chemical methods have been used for such reduction processes. (C) 2010 Elsevier B. V. All rights reserved.