本實驗利用溶膠-凝膠法製備不同Ce掺雜量(0%, 1%, 3%, 5%, 7 at% )之二氧化鈦(TiO2)奈米粉末。所合成之樣品以X光繞射儀 (X-ray diffraction，XRD)、穿透式電子顯微鏡(Transmission Electron microscope，TEM) 、X光吸收光譜(X-ray Absorption Spectroscopy，XAS)、拉曼光譜 (Raman spectroscopy)進行粒徑大小、結晶結構、價態變化及結構變化之分析。透過紫外光-可見光光譜(UV–visible spectroscopy，UV-vis)及光激螢光光譜(Photoluminescence Spectrometry, PL)探討在Ce摻入後的光學性質變化。最後是將奈米粉末與10-5M的亞甲基藍(Methylene blue，MB)水溶液混合後，利用紫外光(Ultraviolet) 照射測試其光觸媒效果。XRD結果顯示，樣品皆為銳鈦礦之結構(anatase)並未產生第二相，結晶性隨著摻雜量的增加逐漸下降。XAS顯示所摻雜的Ce在TiO2內部為混價的形式，且隨著摻雜量的增加，Ti3+、Ce3+與氧空缺的數目皆增加。UV-vis的分析顯示在Ce的摻入後，吸收範圍有延伸至可見光區域，PL光譜強度隨著Ce的增加而逐漸下降，雖然光學分析結果指出摻雜Ce後吸收範圍有延伸至可見光區域，並延緩電子-電洞對複合，但實際量測得到的光觸媒效果沒有提升，推測可能過多的Ce4+ 離子增進了電子-電洞的複合。

In this study, TiO2 nanoparticles doping with different amount of Ce (0%, 1%, 3%, 5%, 7 at%) were synthesized by sol-gel method. X-ray diffraction (XRD), Transmission electron microscope (TEM), X-ray absorption spectroscopy (XAS) and Raman spectroscopy were utilized to characterize the particle size, crystal structure, valence and electronic structure. UV–visible spectroscopy (UV-vis) and Photoluminescence Spectrometry (PL) were used to investigate the change of optical properties after Ce doping. The photocatalytic activity of the samples were evaluated by the degradation of 10-5 M Methylene blue (MB) under ultraviolet irradiation. It is demonstrated that all samples are anatase TiO2 without any second phases. XAS shows that both Ce and Ti were mixed-valence in the samples. With increasing the doping level, the amount of Ce3+、Ti3+ and oxygen vacancies are increased. UV-vis result indicate that absorption range is extended to visible light region and the intensity of PL is reduced. Compared to the doped TiO2, undoped sample shows better photocatalytic activity. It may due to excess Ce4+ appeared in the samples.

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