本實驗以噴霧熱裂解法合成中空二氧化鈰顆粒球，並以初濕含浸法將奈米銀顆粒沉積於二氧化鈰表面。所合成的樣品首先以X光繞射儀 (X-ray Diffraction, XRD)、穿透式電子顯微鏡 (Transmission electron microscopy, TEM)、顯微拉曼光譜儀 (Micro-Raman Spectrometer)，以及X光吸收光譜(X-rays Absorption Spectroscopy，XAS) 分析其成分、形貌、結構與價態變化。由TEM觀察可以得知，噴霧裂解所製成之中空CeO2球直徑約為200奈米至2微米，殼層厚度約為30奈米。所沉積的銀均勻的分佈在球表面上，銀顆粒大小約為5至50奈米，非形成一個連續的殼層；銀顆粒的間距及覆蓋率可由前驅物濃度進行控制。X光吸收光譜與拉曼光譜的測量分析指出，當銀奈米顆粒沉積於中空CeO2球表面時，Ce3+與氧空缺含量皆增加，並且發現有電荷轉移之現象。接著以VSM (Vibrating Sample Magnetometer) 進行室溫下的磁性量測，發現所合成的中空CeO2-Ag具有室溫鐵磁特性 (Room Temperature Ferromagnetism, RTFM)，且經過磁性強度與所沉積的銀數量有關。最後，拉曼光譜量測結果顯示中空CeO2-Ag複合材料能大幅提升表面增強拉曼光譜偵測 (Surface-Enhanced Raman Scattering, SERS)的靈敏度，0.002g的中空CeO2-Ag可偵測到R6G的最低濃度為10-12 M，增強因子(enhance factor)達1011。本實驗成功製備了一種具有室溫鐵磁性及良好SERS效果的多功能複合材料。

In this study, hollow CeO2-Ag composite ((H)CeO2-Ag) was prepared by two-step process. Hollow CeO2 spheres were synthesized by Spray Pyrolysis process at first, and then Ag nanoparticles were deposited on sphere surface by incipient wetness method. X-ray Diffraction (XRD), Transmission electron microscopy (TEM), X-rays Absorption Spectroscopy (XAS) and Raman were utilized to investigate the morphology, structure and valence state of cations. VSM (Vibrating Sample Magnetometer) and Raman spectrometer was utilized to measure magnetic behavior at room temperature and Surface-Enhanced Raman Scattering (SERS), respectively. Microstructural investigations demonstrated that the radius of hollow CeO2 sphere ranges from 200 nm to 2 µm with the shell thickness of sphere was about 30 nm. Silver nanoparticles which of size vary from 5 to 50 nm randomly distributed on the surface of sphere. Both of the size of silver nanoparticles and the coverage of silver nanoparticles on CeO2 sphere can be tuned by adjusting the concentration of precursor. XAS analysis predicted that defects were introduced after depositing silver nanoparticles. Moreover, charge transfer between silver and CeO2 was observed. All (H)CeO2-Ag composites were ferromagnetic at RT. Notably, the sensitivity and enhance factor of SERS was significantly improved. This study successfully synthesis a multifunction- material contain SESR effect and RTFM.

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