【作者】 姜妍彦；

【导师】 宁桂玲；

【作者基本信息】 大连理工大学 ， 化学工艺， 2008， 博士

【摘要】 AB₂O₄型化合物以其丰富的结构和优异的磁、光、电、催化等特性吸引了人们极大的关注。本论文以具有光诱导（光催化、光致发光）功能特性的AB₂O₄型化合物为对象,主要研究了AB₂O₄型尖晶石结构化合物的合成、可见光催化性能和凝聚态特征;同时对SrAl₂O₄:Eu,Dy长余辉发光面板一步合成工艺和玻璃复合发光体发光性能进行了研究。具体内容如下:1.研究了XAl₂O₄（X=Mg,Zn,Cu）和ZnY₂O₄（Y=Cr,Mn,Fe）尖晶石化合物的合成、结构、可见光催化活性及结构-性能的关系。利用XRD、TEM和UV-Vis漫反射吸收光谱考察和分析了化合物的晶体结构、微观形貌和光谱响应特性。结果表明,合成的样品均具有尖晶石结构,颗粒尺寸在10-40 nm之间,吸收带边不同程度地进入可见光区域,特别是CuAl₂O₄光吸收几乎覆盖整个可见区。在对甲基橙、酸性红B和活性艳红K-2G水溶性染料的光催化降解实验中,化合物由于晶体结构和带隙结构的差异而表现出不同的可见光催化活性,其中CuAl₂O₄的可见光活性最为突出,对三种水溶性染料的2h降解脱色率均达到98%以上。2.研究了高活性CuAl₂O₄光催化剂的合成及其可见光催化性能。XRD、TEM和紫外-可见漫反射光谱的研究表明,在700℃下焙烧2h,前驱体可成功转化为纯相CuAl₂O₄纳米粉体,产物在紫外区和可见区均具有很高光吸收能力。以甲基橙、酸性红B和活性艳红K-2G水溶性染料为模拟降解液进行了CuAl₂O₄可见光催化性能的研究,考察了焙烧温度、辐射光源（紫外光、可见光、太阳光和暗室）、辐射波长、染料结构和催化剂用量对CuAl₂O₄可见光活性的影响,并对CuAl₂O₄光催化剂的循环使用稳定性进行了研究;提出了光辐照时引起的脱色现象是光催化降解反应的结果,无光照射时的脱色现象是催化剂活性表面对染料吸附作用的结果;从CuAl₂O₄光催化活性与辐射波长的关系,进一步证明染料的脱色反应确实是受光驱动的。3.研究了纳米CuAl₂O₄的软化学形貌制备,并对这些凝聚态形貌进行了数学表征。本论文采用溶胶.凝胶法、共沉淀法、聚合物配位法和硬脂酸凝胶法,同时辅以表面活性剂,合成得到球形、棒状、无规则颗粒等多种形貌迥异的纳米粉体,DRUV-Vis吸收光谱分析表明不同凝聚态形貌具有不同的光谱响应特性;采用分形维数D定量描述了各种凝聚态粉体的不规则程度,并探讨了D值大小对催化剂可见光活性和光催化动力学过程的影响。4.研究了一种一步法合成SrAl₂O₄:Eu,Oy（SAED）长余辉发光面板的新方法,并对其发光性能进行了研究。本方法将Eu₂O₃、Dy₂O₃和Sr（NO₃）₂涂覆在氧化铝基片表面,利用其表面上的Al₂O₃源通过高温固相反应,成功制备出SAED长余辉发光面板。重点探讨了工艺条件（合成气氛、合成温度、保温时间）、助溶剂用量对发光表面晶体结构及发光性能的影响,得出了最佳工艺条件。5.合成了SrAl₂O₄:Eu,Dy掺杂SrO-Al₂O₃硼硅玻璃发光复合材料。重点研究了玻璃母体中Al₂O₃与SrO含量以及微量铁存在对复合材料发光性能的影响,同时也研究了合成温度、保温时间和气氛条件对复合材料发光性能的影响。SEM观察和荧光光谱分析表明,发光特性源于镶嵌于玻璃介质中的SAED晶体颗粒,但玻璃介质成分对复合体的发光强度有很大影响。随着玻璃介质中Al/Sr比率的增大,复合体发光强度有着明显的提高;而玻璃介质中微量Fe₂O₃的存在,则使发光强度和余辉初始强度明显降低。更多还原

【Abstract】 The compounds with a molecular formula of AB₂O₄ have drawn attention because these materials have various crystal structures and excellent magnetic, optical, electrical and catalytic properties. In this dissertation, the focus of the studies is on AB₂O₄ compounds with the light-induced function （photocatalysis and photoluminescence） , including two parts: the first is to involve studies on the synthesis, photocatalytic performance under visible light, and characteristics of structure and morphology of AB₂O₄ -spinel materials; the other is on the studies of a one-step process for synthesizing SrAl₂O₄: Eu, Dy long-afterglow luminescent plate, and the luminescence performance of SrAl₂O₄: Eu, Dy composite glasses. Detailes are as follows.1. The synthesis, structure, visible-light photocatalytic activities and the relationship between the structure and performance of spinel compounds, XAl₂O₄ （X = Mg, Zn, Cu） and ZnY₂O₄ （Y = Cr, Mn, Fe）, were investigated. Their crystal structure, microscopic morphology and spectral response characteristics were analyzed via. XRD, TEM and UV-Vis diffuse reflectance spectra. The experimental results show that all the samples have spinel structure with particle sizes of 10-40 nm, and their absorption band-edges are able to extend to the visible-light region in varying degrees. In particular, the sample of CUAl₂O₄ has its absorption spectrum covering nearly the whole visible-light region. From photocatalytic degradation of methyl orange, acid red B and reactive red K-2G aqueous dyes, it was found that the sample materials exhibited different visible-light photocatalytic activities due to the differences in crystal structures and band gaps of these materials. Of all these materials, CUAl₂O₄ presented the highest photocatalytic activities with＞98% decolorization rate for all three aqueous dyes after two hours.2. The synthetic process and photocatalytic properties of CUAl₂O₄ with a high activity under visible-light irradiation were studied. The results from XRD, TEM and UV- visible diffuse reflectance spectra show that the precursor was successfully transformed to single-phase CUAl₂O₄ nanoparticles calcined at 700℃for 2 hours in the air, and the products have strong absorption ability in UV and visible light range. Using methyl orange, acid red B and reactive brilliant red K-2G aqueous solution as model compounds, we investigated the effects of calcining temperature, irradiation light source （UV light, visible light, sunlight, and dark room）, irradiation wavelength, dye structure, and catalyst dose on the visible-light photocatalytic activity of CUAl₂O₄. In addition, the recycling stability of CuAl₂O₄ was studied. From the experimental results, it is proposed that the decoloration of dyes under irradiation condition is caused by photocatalytic degradation and the decoloration in the absence of light is due to the surface absorption of the dyes by the catalyst. Furthermore, the wavelength dependence of the photocatalytic activity of CuAl₂O₄ can be further suggested that the decorloration reaction is driven by light.3. The morphological formation, the characterizations and the effects on photocatalytic activity of CuAl₂O₄ nanoparticles via. various soft chemistry methods were studied. Nanopowders with various morphologies （such as spherical, rod-like, and irregular grain） were obtained by various methods including the sol-gel, precipitation, polymerizable complex and stearic acid gel. UV-Vis diffuse reflection spectra analysis show that the sample powders with different morphologies exhibited different spectral responses. The morphological irregularity of sample powders was quantitatively described by calculating the fractal dimension D of these samples. The effects of the D value on photoactivity and dynamics process for photocatalytic reaction were discussed.4. A novel one-step systhesis process for making SrAl₂O₄:Eu,Dy（SAED） long-afterglow plate was invented and the luminescence properties of the material were evaluated. A S AED long-afterglow luminescent plate was successfully prepared by solid-state reaction method using Al₂O₃ substrates coated with Eu₂O₃, Dy₂O₃ and Sr （NO₃）₂ materials. The effects of synthetic condition （synthetic atmosphere, calcining temperature and holding time） and additive amount （H₃BO₃） on the surface structures of Al₂O₃ substrates and their luminescence properties were investigated. And the optimal synthetic conditions were obtained.5. SAED（SrAl₂O₄.Eu,Dy） doped SrO-Al₂O₃ borosilicate glass composite materials were synthesized. The luminescent properties with the Al₂O₃ and SrO content, as well as minute amount of iron in glass host were studied. In addition, the influence of synthetic temperature, holding time and atmosphere on their luminescence properties was studied. SEM and emission spectra show that the fluorescence characteristics of these samples were originated from the SAED grains embedded in the glass host. However, the intensity of their luminescence is largely influenced by the glass host compositions. With the increase of Al/Sr ratio in the glass host, the composite luminescence intensity increased significantly. The presence of minute amount of Fe₂O₃ had no influence on the spectral characteristics of the luminescence, but made significant decreases in the luminescence intensity and initial afterglow intensity.更多还原