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Ⅰ. High ligand A1 aluminum phosphate backbone of the research Ⅱ. Zeolite -based Composite nonlinear optical material exploration and research

Author: ZhangLei
Tutor: LongYingCai
School: Fudan University
Course: Inorganic Chemistry
Keywords: High- coordinated aluminum Aluminum phosphate backbone Rare earths AlPO-CJ2 AlPO-21 Zeolite -based Composite Nonlinear optical material
CLC: TB383
Type: PhD thesis
Year: 2003
Downloads: 160
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Abstract


This mainly includes the following two aspects: 1: microporous aluminophosphate AlPO-CJ2 as a substrate doped rare earth (RE) Eu structural characterization and properties; 2: Common template synthesis of microporous aluminophosphate AlPO-21 and Analysis and Adsorption of its structure. In the 1940s, the first human synthetic zeolites. Research shows that zeolite is a type of stone structure having a regular pore aluminosilicate, a skeleton is composed of silicon and aluminum tetrahedral SiO4 tetrahedra AlO4 connected together. To the 1980s, people first artificial synthesis of aluminophosphate molecular sieves (AlPO-n), which is a synthetic zeolite milestone. Was synthesized AlPO-n The structure is composed of phosphorus and aluminum tetrahedra PO4 tetrahedra AlO4 components. In a later series of synthetic AlPO-n, not only the known structure of zeolite with AlPO, but also found a number of new structures AlPO. AlPO-n the significance of the discovery is that it can only be broken by a zeolite of silicon and aluminum tetrahedra SiO4 tetrahedra AlO4 composed of traditional values. Since then, people can explore a wider range of new zeolite synthesis. Recent advances include synthetic ZnPO4, CdPO4, CoPO4 other people break through the traditional concept bound result, this kind of zeolite catalysis, adsorption and separation applications such as exhibit many unique properties. Aluminophosphate molecular sieves in the discovery process, a class with a greater difference between the traditional zeolite AlPO been synthesized that contain high coordination number of Al AlPO. This type of pore structure contained in the skeleton AlO5 trigonal bipyramid, AlO6 octahedral basic structural unit. Studies on the structure of such materials allows us to further the understanding of zeolite, namely zeolite skeleton may not be entirely constituted by the tetrahedron, the other under appropriate conditions polyhedron can become the basic structural unit of the skeleton. The research work is mainly based on two high-coordinated Al containing microporous aluminophosphate structure AlPO-CJ2 and AlPO-21 expanded. AlPO-CJ2 from Jilin University in dragons first synthesized in 1990 a new type of aluminum phosphate microporous structure. Its skeleton by the phosphorus and aluminum oxide PO4 tetrahedra tbp AlO5, octahedral AlO6 aluminum or aluminum oxyfluoride octahedra AlO5F components. In this work we Al2O3-P2O5-NH4F-H2O and Al2O3-P2O5-CO (NH2) 2-NH4F-H2O two systems synthesized AlPO-CJ2, and proved true templating agent is not an organic amine, but ammonium ion. Since there are a lot of backbone end groups oxygen, so that the structure of AlPO-CJ2 poor thermal stability (over 200 degrees skeleton collapse). Thus, the aluminum phosphate microporous structure, although very new, without much practical use. We are through the AlPO-CJ2 structured data found in the skeleton of aluminum oxide end groups formed Al-O bond lengths than the oxygen bridge bond of Al-O bond length is shorter about 0.1?. As end group has a relatively high oxygen electron density, it is possible by electronic charge transfer transitions energy absorption process. Such structural features in a number of light-emitting materials can often be seen. Thus, we were inspired, consider AlPO-CJ2 as a matrix for the luminescent material. Because of the presence of charge transfer, the matrix energy absorption increases if the center of the matrix of the light emitting efficiency of the energy transfer, it is possible to obtain very excellent light. Under certain conditions, even without the emission center can be born charge migration itself luminous efficiency. Taking into account the structural features of AlPO-CJ2, we will make a rare earth element Eu lt; WP = 5 gt; as the luminescent center doped in AlPO-CJ2, get a hetero atom skeleton of Eu AlPO-CJ2 (EAPO) Compound thereof. The complexes of XRD showed that the skeleton structure and AlPO-CJ2 structure is very similar, Eu does not result in the introduction of changes in the skeleton obvious, but much larger than the radius of Eu Al, so that there was a serious polyhedron distortion, which leads to the symmetry of the compound of the subtle changes appear. ICP analysis showed that the data, Eu content is very low therein, the atomic ratio of Eu: Al: P = 0.058:0.917:1. Because (Eu + Al): P? 1, so we may replace Al infer the location of Eu. In order to study the state in which the Eu and position of the compound of the Mossbauer us a test signal. The results showed that, Eu +3 in which is, at a lower symmetry environment. 31P MAS NMR data show, AlPO-CJ2 the two crystallographic position signal P chemical shift changes the compound, in both the main signal in the two shoulder signals appear. This is further described in the backbone are substituted Eu Al position, and thus the impact of P nuclear magnetic resonance signal. Fluorescence analysis showed that the excitation spectrum contains a charge transfer band, and the emission spectra show, Eu low symmetry environment, should belong to the C1, C2 or Cn point group, which we infer Eu should replace Al (V) position . The significance of the above work is that, under hydrothermal conditions (200? C less), Eu strong elements of the metal and the skeleton O atoms can form a covalent bond, which is not easy. Generally only the high temperature solid phase reaction, Eu and other elements can form a covalent bond. These studies on the synthesis of novel catalyst has a certain significance. Because in the past, people hoping catalytic properties of rare earth elements and molecular sieves combined to obtain efficient catalysts. Conventional ion exchange method, a catalyst obtained by this method shorter life because RE easily lost. If RE backbone atoms can form, may get more excellent catalysts. The second part of this article is another multi-ligand Al containing aluminum phosphate AlPO-21 molecular sieve structure and nature of research. AlPO-21 was first synthesized in 1982, and its structure was identified in 1985. And later under other conditions synthesis AlPO-21. Analysis indicated that the different conditions of AlPO-21 with some differences. This work is based on a total of RB and diethylamine as templating agent (co-template), with water - ethanol as dual solvent synthesis. The data show that the single crystal analysis, AlPO-21 containing the skeleton of Al (IV) and Al (V) bit two configurations aluminum. However, doublet splitting 10.02 degrees with the temperature suggests that node?

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