Abstract
Abstract TMC have special physical and chemical properties. They have the properties of covalent solids, ionic crystals, and transition metals at the same time. They are applied in a variety of processes, such as dehydrogenation, hydrogenation, and hydrogenolysis. Due to their comparable performance, TMCs are the potential substitutes for the expensive Pt-group metals in catalysis applications. Therefore, they attract intense interests in both fundamental researches and industrial applications. Transition metal carbides are divided into four groups: bulk carbides, carbide-modified surfaces, carbide thin films, carbide clusters. Our carbonization experiment is focusd on carbide-modified surfaces of Mo(110). Although the crystal structure of carbide-modified surfaces is not as good as bulk single crystal carbides, its qualities, such as electric conductivity, thermal conductivity, hardness, and melting temperature, can be controlled via the carbon/metal stoichiometry. In the literature, the researches of carbide surface structures mostly confine to observation of LEED and AES, the real structure of carbide surfaces is still not clear. This experiment is divided into two parts. Firstly, carbide overlayers were fabricated on clean Mo(110) surfaces. The tunable parameters include exposures, temperature during carbonization, annealing temperature, annealing time. The relations between carbide surface structures and varing parameters were investigated by LEED and STM. Secondly, oxygen exposure on carbide surfaces, the reactivity of carbide structures on oxygen was compared before and after exposure of oxygen by STM.