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以硝酸铈(Ce(NO3)3·6H2O)、硝酸铕(Eu(NO3)3·6H2O)、氨水(NH3·H2O)为原料和十六烷基三甲基溴化铵(CTAB)为分散剂,采用水热法制备了CeO2:Eu3+纳米晶,用X射线衍射(XRD)、X射线光电子能谱分析(XPS)、透射电镜(TEM)、傅立叶红外(FT-IR)、拉曼光谱和荧光(FL)等手段对产品的结构和光学性能进行分析和表征。测试结果表明:CeO2:Eu3+是立方萤石结构的纳米晶体,铕以Eu3+形式进入CeO2晶格中致使其晶胞参数略增,晶粒尺寸减小。相比纯CeO2,CeO2:Eu3+的紫外-可见光吸收边发生些许红移,其中CeO2:Eu3+(9.0%)纳米晶的能带隙为2.84 e V。CeO2:Eu3+纳米晶在593,612和632 nm处发橙红光,其中非直接激发(356 nm)的CeO2:Eu3+(1.0%)的磁偶极跃迁(5D0→7F1)占主导,而直接激发(468 nm)的CeO2:Eu3+(5.0%)的电偶极跃迁(5D0→7F2)强度更大,两者均随焙烧温度升高而增强。
The catalysts were prepared by using Ce (NO3) 3.6H2O, Eu (NO3) 3.6H2O, ammonia (NH3 H2O) as raw materials and cetyltrimethylammonium bromide (CTAB) as dispersants , CeO2: Eu3 + nanocrystals were prepared by hydrothermal method and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and fluorescence (FL) and other means of product structure and optical properties were analyzed and characterized. The results show that CeO2: Eu3 + is a cubic fluorite-structured nanocrystal. When europium enters into the CeO2 lattice with Eu3 +, the cell parameters are slightly increased and the grain size decreases. Compared with pure CeO2, CeO2: Eu3 + shows a slight red shift at the UV-Vis absorption edge, and the band gap of CeO2: Eu3 + (9.0%) nanocrystals is 2.84 eV. CeO2: Eu3 + nanocrystals emit orange-red light at 593, 612 and 632 nm, with the dipole transition (5D0 → 7F1) dominated by indirect excitation (356 nm) of CeO2: Eu3 + ), The electric dipole transition (5D0 → 7F2) of CeO2: Eu3 + (5.0%) is more intense, both of which increase with increasing calcination temperature.