Preparationlication, Characterization And Application Of Microporous Composite Materials

With the continuous progress of science and technology, the performance ofthe single-component materials has been unable to meet the growing demand forpractical application. Composite materials have displayed a variety of novelproperties and superior performance which are not available in the single-componentmaterials. Therefore, the research on the composite materials underwent a rapiddevelopment in the past two decades. More and more new composite materials havebeen synthesized, and their specific properties have shown good prospects forapplications. Among the inorganic composite materials, microporous molecularsieve is undoubtedly one of the most ideal host materials. Its special pore structureand good mechanical and thermal stability make it favored by scientific researchers.Molecular sieve-based composite materials have great applications in a variety range.For example, in the field of gas storage and separation, drug delivery, industrialcatalysis and so on, they have exhibited good performance and promoted the relatedresearch. Therefore the exploiture of molecular sieve-based composite materials hasa great significance both for the scientific research and the practical application.In this paper, firstly, microporous molecular sieve was chosen as the hostmaterials to synthesize a series fluorescent composite material with goodphotoluminescence performance. Secondly, on the basis of previous work, we usethe synthesized molecular sieve-based composite materials and biomaterial defoliation as the raw material to prepare two kinds of water-soluble carbogenicnanoparticles. These nanoparticles are almost nontoxic for human cells and idealcellular imaging agents. Finally, according to the principles of CVD, a set of vacuumchemical vapor reaction system was designed, which was used to prepare zincphosphide and zinc nitride semiconductor nanomaterials in the host microporousmolecular sieve. This thesis is divided into four parts.In chapter one, we introduced the research background of this thesis andsummarized the development process and status of host-guest composite materials.Then emphasis was given to the prospect of porous material-based luminescentmaterial on the development of its synthesis and property, as well as the practicalapplication and potential barriers of luminescent material in the biomedical field.After that, we focused on the situation of low-dimensional materials synthesized inthe condition of vacuum. Finally, the significance and achievement was brieflydescribed.Well-defined synthesis conditions allow microporous molecular sieve materialsto be highly transparent in the UV and visible regions. In chapter two, CNP-loadedmagnesium-aluminophosphate solid phosphors have been prepared through thermaldecomposition of the occluded template or loaded organic molecules. It is revealedthat the carbogenic species in the phosphors is responsible for the observedphotoluminescence, and the emission wavelength depends on the carbon content inthe materials. XPS and ESR spectroscopies demonstrate that the PL property arisesfrom defects which render electron localization in the CNPs possible. Uponirradiation with UV light, the surface states with the localized electrons in the CNPsare excited, whereas the radiative relaxation of the excited surface states releasesenergy, emitting visible light. The emission intensity is also correlated with thecarbon content in the phosphor materials. At a lower carbon content, the emissionintensity increases with the content, whereas at a higher carbon content, the emissionintensity is inversely proportional to the content because of the competition betweenconcentration contribution and quenching of the luminescent centers in the phosphor. These phosphor materials possess high thermal stability and tunable emissionwavelength. Through varying the thermal treatment condition, the emissionwavelength can be tuned from420to550nm.In chapter three, we use an aqueous route to synthesize three samples of watersoluble carbogenic nanoparticles. The solid phosphors in the previous chapter and twokinds of biomaterial defoliation were used as the raw materials. Their performance inphotoluminescence, cytotoxicity and cellular imaging was investigated in detail. Theresults showed that, the defoliation-derived carbogenic nanoparticles exhibited thetypical excitation-dependent emission, which may reflect not only effects fromparticles of different sizes in the sample but also a distribution of different emissivesites on the carbogenic nanoparticles. On the other hand, the solid phosphor-derivedsample displayed the excitation-independent emission, implying its relatively simplechemical environment. All the three samples have good photostability and are stablein a solution at high ionic strength of5M. NaCl. In the HeLa cell survival test, all thecarbogenic nanoparticles exhibited low cytotoxicity. Especially in the highconcentration, the performance of all the samples were superior to that of thetraditional quantum dots, which render them better prospects for the biologicallabeling. In the following cell imaging to human embryonic kidney cells, all thesamples enter into cells without any further functionalization, and exhibit obviousphotoluminescence signal. In particular, the solid phosphor-derived sample penetratedinto the karyon without the modification with specific transferrable protein, and usingits fluorescence property, it is possible track the carbogenic nanoparticles. All thebiological results indicates that the three samples of carbogenic nanoparticles is ableto used as fluorescent probe molecules in cellular imaging and bio-detection.Moreover, there is no distinct difference in the photoluminescence property,cytotoxicity, and cell labeling results of these two kinds of defoliation-derivedcarbogenic nanoparticles, suggesting that the aqueous route we used for thepreparation of water soluble carbogenic nanoparticles is generally universal, and maybe extended to various defoliations. In chapter four, the elemental zinc was introduced into the cages of microporousmagnesium-aluminophosphate and silicoaluminophosphate molecular sieve,respectively, using the designed vacuum chemical vapor reaction system. Elementalzinc reacted with the proton in the framework and the univalent zinc was generated.For the magnesium-aluminophosphate system, the formation of univalent zinc leadedthe dephosphorization on the framework. The removed phosphorus reacted withpartial univalent zinc, and generated zinc phosphide. We use the zincphosphide-loaded composite material as the evaporation source to synthesize a seriesof low-dimensional nanostructures of zinc phosphide on one substrate, includingnanoparticles, nanowires, and dense zinc phosphide films. The results show that thegrowth of zinc phosphide nanostructures follows the vapor-solid mechanism. On theother hand, for the silicoaluminophosphate system, ammonia molecules areintroduced into the univalent zinc-contained molecular sieve in sequence. At roomtemperature, the univalent zinc reacted with ammonia, resulting in zinc nitride in themicroporous, and the reaction is exothermic. The resulted zinc nitride-loadedmicroporous composite material displayed a certain room temperaturephotoluminescence. Since the high temperature or complicated equipment is alwaysneeded in its preparation, zinc nitride directly synthesized from ammonia at roomtemperature have not been achieved yet prior to our work.