摘要
利用有机相-水相界面共沉淀溶胶支持自组装方法制备粒径为15nm、孔径为8nm的分子筛Eu-MCM,它拥有734m2/g的比表面积和1.49cm3/g的比孔容.把TiO2组装到Eu-MCM的孔道中,组装成TiO2/Eu-MCM纳米复合材料.XRD,RAMAN和选区电子衍射花样分析表明纳米复合材料中的TiO2为锐钛型.TiO2/Eu-MCM的发光表现为Eu3+离子的特征光谱,激发峰分别为342(5L10),358(5L9),378(5L7),390(5L6),411(5D3),462(5D2)和524(5D1)nm;发射峰为579,592,613,653和701nm,归属于5D0→7FJ(J=0,1,2,3,4)组态间的跃迁.纳米复合材料的发光强度都要比Eu-MCM的发光强,其中43%TiO2/Eu-MCM的发光最强.荧光和紫外漫反射结果表明客体TiO2对主体分子筛存在能量传递效应.在微弱的紫外灯光照射下,TiO2/Eu-MCM纳米复合材料对苯酚的光催化氧化性能和其发光强度具有一定的相关性.29%TiO2/Eu-MCM的纳米复合材料拥有的比表面积、孔容和孔径分别为204m2/g,0.24cm3/g和4.7nm.29%TiO2/Eu-MCM对苯酚具有68%的最高光催化氧化产率和85%催化氧化选择性.
The nanosized luminescent Eu-MCM, which possesses regular uniform particles with a diameter of 15 nm, an enormous specific area of 734 m(2)/g, a large porosity of 1.49 cm(3)/g, and an ultra large pore of 08 rim, was synthesized by means of sol-gel-assisted self-assembly at the interface of the non-aqueous phase and the aqueous phase. The nanosized supramolecular materials of TiO2/Eu-MCM were prepared by the method of supramolecular encapsulation with TiO2 as the guest encapsulated in the channels of the host Eu-MCM. The experiments of XRD, RAMAN, and selected area electron diffraction pattern showed the anatase of TiO2 in the TiO2/Eu-MCM. The TiO2/Eu-MCM possesses the typical fluorescent spectra of Eu3+ ion: The excited-states at L-5(10) (342 nm), L-5(9) (358 nm), L-5(7) (378 rim), L-5(6) (390 nm), D-5(3) (411 nm), D-5(2) (462 ran), and 5 D, (524 nm); the emission peaks at 578, 590, 613, 654, and 703 nm, corresponding with the transitions D-5(0) -> F-7(J) (J = 0, 1, 2, 3, 4), respectively. The luminescent intensity of the TiO2/Eu-MCM is much stronger than that of the Eu-MCM and the pure powder of TiO2. The intensity of the 43%TiO2/EU-MCM is the strongest. The experimental results of fluorescence and UV-vis diffuse reflectance showed the effect of energy transfer of the guest TiO2 to the host Eu-MCM. The photocatalytic oxidation of the phenol aqueous solutions with very weak UV light over the TiO2/Eu-MCM was investigated. The specific photocatalytic reactivities of the TiO2/Eu-MCM with 16%-53% TiO2 were found to be much higher than that of the pure powder of TiO2 and the Eu-MCM. The fluorescent intensity and the photocatalysis of the nanosized TiO2/Eu-MCM have a certain extent relation. The nanosized 29%TiO2/Eu-MCM with the specific area of 204 m(2)/g, the porosity of 0.24 cm(3)/g, and the aperture of 4.7 nm possesses the highest photocatalytic reactivity (68%) and the excellent selectivity of oxidation (85%).
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2005年第13期1193-1200,i002,共9页
Acta Chimica Sinica
基金
广东教育学院教授博士专项经费
中国科学院长春应用化学研究所稀土化学与物理开放实验室基金(No.R050002K)资助项目
