Scanning Tunneling Microscopy Study Of Molecule Adsorption On Rutile Titanium Dioxide Surface

As a powerful tool, Scanning Tunneling Microscopy (STM) plays an important role in various research fields, including physics, chemistry, biology, material and et.al. In this thesis, we studied the adsorption, diffusion and reaction of molecules (CO, CO2, O2) on rutile TiO2(110) surface.In chapter 1, we introduced the fundamental principles and the structure of the STM used in our experiments, and the density function theory (DFT) used in the relevant theoretical calculations. Then, we reviewed the most distinguish work to discuss the analytical and research method in surface science system.In chapter 2, we introduced the catalysis and applications of TiO2, and analyzed the structure and characteristic of TiO2(110) surface in details. And we carried out the in-situ STM experiment in CO adsorption on rutile TiO2(110) surface. Our results show that CO molecules preferentially adsorb at the next nearest-neighbor Ti50 atoms close to the Obr vacancy, which disagrees with the widely-accepted idea that the OV acts as an adsorption site for CO.In chapter 3, we reported the investigation on the adsorption behaviors of CO molecules on the rutile TiO2(110) surface with O adatoms. We found that the diffusive CO molecules can be trapped by the 0 adatoms to form stable CO-0 and CO-O-CO complexes. Through STM combined with DFT calculation, CO oxidation at low temperature was further discussed on TiO2(110), which would help our understanding of TiO2 catalysis process.In chapter 4, we investigated the adsorption sites of CO2 at various coverages on reduced TiO2(110)-1×1 surface. By injecting electrons to adsorbed CO2 with the STM tip, the initial activation of CO2 was mimicked and the energy for CO2 activation was obtained.