本研究利用共沉澱法製備未摻雜和摻雜11at%Cr之二氧化鈰奈米顆粒，在300℃不同氣氛(O2、Ar、Ar+H2)下進行退火，以控制CeO2的缺陷數量，再利用程溫還原(Temperature Programmed Reduction，TPR)實驗觀察不同缺陷含量之CeO2在不同溫度下改變與氫氣的反應關係。樣品的結構、尺寸及元素價態則以X 光繞射儀 (XRD)、場發射穿透式電子顯微鏡，及X光吸收光譜 (X-ray AbsorptionSpectroscopy，XAS) 進行。實驗結果顯示，在300℃下進行退火，CeO2奈米顆粒中的缺陷分布主要集中在表層，此種分布將影響樣品的還原能力，而Cr的摻雜將下一步改變CeO2與H2的反應。當樣品中的Cr為六價時，由於Cr亦反應，CeO2的還原能力將大幅提高。當樣品中的Cr為三價時，由於Cr周圍的結構變化，提高CeO2可產生還原反應的缺陷濃度。

In this study, the undoped and Cr-doped CeO2 nanoparticles were prepared by the co-precipitation methods, annealed to 300℃ n different atmospheres (O2, Ar, Ar + H2) to control the amounts of defects in the CeO2, and thenthe temperature programmed reduction (Temperature Programmed Reduction, TPR) experiments observed different defect content of CeO2 change reaction with hydrogen at different temperatures. The structure of the sample size and element valence state while the X-ray diffraction (XRD), field emission transmission electron microscopy, and X-ray absorption spectroscopy (X-ray AbsorptionSpectroscopy, XAS). The experimental results show that annealing at 300℃, the defect distribution of CeO2 nanoparticles are mainly concentrated in the surface, such a distribution will affect the reducing capacity of the sample, the next step change of Cr-doped CeO2 and H2 reaction. Of Cr in the samples for hexavalent Cr also reaction of CeO2 reduction capacity will substantially increase. When the product of Cr trivalent Cr around the structural changes to improve the CeO2 can produce a reduction reaction of the defect concentration.

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