| Summary: | 碩士 === 國立臺灣科技大學 === 材料科學與工程系 === 101 === Fe-doped TiO2 NPs prepared by sol-gel method were investigated by using X-ray Absorption Spectroscopy (XAS) and Raman spectroscopy. The crystal structure and particle size was characterized by X-ray diffraction spectroscopy (XRD).
X-ray absorption near edge structure (XANES) of Fe L and K edge show that the valence of Fe in the Fe-doped NPs is 3+ and is independent with the concentration of dopant. Extending X-ray Absorption Fine Structure (EXAFS) revealed that the Fe3+ replaces the Ti4+.The O K edge indicated that the hybridization between Ti 3d and O 2p changed as doping with Fe. Ti L and K edges demonstrated that Fe doping results in the disorder of TiO2. The change in coordinated environment was observed, which possible indicative the formation of oxygen vacancy. Raman peaks shift toward higher wavenumber as doping Fe, which indicative the formation of oxygen vacancy..
Under the oxidizing atmosphere (O2), the oxygen vacancies of the annealing sample decrease along with the dopant Fe；under the reducing atmosphere (Ar+3%H2), the second phase ilmemite is found in Fe-doped sample. This second phase inhibit the formation of oxygen vacancies generated.
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