Scanning Tunneling Microscopy Study Of The Rutile TiO₂(110) Surface

Scanning Tunneling Microscope(STM),as a powerful tool,has been widely utilized in physical science,chemistry,materials science and biology.In this thesis, we studied the surface texture and molecular adsorption taking advantage of UHV LT-STM and VT-STM,and manipulated the oxygen vacancies using the STM tip.In Chapterâ… ,we introduced the fundamental principles and the structure of the STM used in our experiments,and discussed the analytical and research method in surface science system.At the same time we simply introduced the density function theory used in our theoretical calculations.In Chapterâ…¡,we introduced the catalysis and applications of TiO₂,and analyzed the structure and characters of TiO₂(110) surface in detail.We got different TiO₂(110) surface structure under different conditions for the following experiments.In Chapterâ…¢,the interaction of TiO₂ surface and water was discussed.We found that the hydroxyls,as the direct products on the oxygen vacancies,had great significance on TiO₂ surface.The hydroxyls decomposition course on the surface and the image reverse property were analyzed systematically,which facilitated us distinguishing the hydroxyls from oxygen vacancies.In Chapterâ…£,we produced a new type defect,the oxygen vacancy pair(OVP), under the STM tip inducement.The OVP is not only as a medium during the OVs diffusion,but also has higher catalytic activity than OV.The OVP mid-states is very helpful to understand reaction mechanism and the surface diffusion of atoms and molecules,and also is very important to comprehend the catalytic reactions on TiO₂(110) surface.In Chapterâ…¤,we introduced the adsorption and dissociation of small molecules such as CO and O₂ on TiO₂(110) surface,and compared the different adsorption structure of O₂ on defective and defect-free TiO₂(110) surface.We also probed the CO adsorption and diffusion on the surface.