為瞭解在二氧化鈦(TiO2)中摻雜鐵(Fe)對其缺陷結構之影響，本研究以溶膠-凝膠法(Sol-gel)製備摻雜不同比例Fe之 TiO2奈米粉末，利用X光繞射(X-ray diffraction)、X光吸收光譜(X-ray absorption spectroscopy)以及拉曼光譜(Raman spectroscopy)分析其晶格及電子組態，探討摻雜鐵的TiO2奈米顆粒中的缺陷結構變化。
首先，由X光吸收光譜的Fe-L edge及Fe-K edge發現所摻雜的鐵離子在TiO2中以三價的形式存在。延伸精細結構(EXAFS)的分析則顯示，Fe離子與結構中的Ti離子形成置換。而O-K edge結果則指出鐵的摻雜造成Ti與O間的能帶結構產生變化。由Ti L及K-edge得知Ti的配位數隨著鐵摻雜量增加而下降顯示氧空缺的產生。拉曼光譜則發現鐵的摻雜會提高TiO2樣品中的氧空缺數量。
摻雜不同比例Fe之 TiO2奈米粉末經由氧化退火處理後，發現Fe摻雜對存於TiO2結構內的氧空缺有明顯減少的趨勢，且摻雜量越高，減少的數量越多；經由還原退火處理後，發現Fe的摻雜在TiO2結構內產生第二相鈦鐵礦(ilmenite)，且摻雜量越高，產生的數量越多。此第二相的生成改變Fe的價態及抑制樣品中氧空缺的數量。

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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