Synthesis And Applications Of Ordered Mesoporous Metal Phosphonate And Sulfonate Materials

Environmental pollution and energy crisis have become two of the most serious problems with the rapid development of the modern society. In response to those petroleum crisis and environmental problems, the principles of green energy and sustainable living movements gain popularity. Development of multifunctional and advanced energy materials is essential for alternative and renewable sources, reducing emission of harmful substances, clean production, as well as attaining stable energy provision. Chemically designed mesoporous organic-inorganic hybrid solids are considered to be promising candidates for environmentally friendly materials with multifunctionality, which have attracted much attention because of the combination of superior properties due to the organic and the inorganic components.They are not just physical mixtures of organic and inorganic moieties, but considered as nanocomposites with organic and inorganic components that are intimately mixed on a molecular level. The incorporation of mesoporosity with extra large surface area, pore size and pore volume could contribute to the enhanced performances in gas storage, catalyst supporting and macromolecule adsorption.Periodic mesoporous organosilicas (PMOs), which contain organic groups in siloxane bridges of the silica framework, were the most widely investigated. However, besides the limited choices and the high cost of the organosiloxane, the functions of silica are limited to physical properties concerned with catalytic supports and adsorbents. Thus, the preparation of porous hybrid materials was further extended to non-silica-based organic-inorganic hybrid mesoporous materials, in which the metal phosphonate mesoporous materials are one of the important families. Organophosphorus acids and their derivatives (salts, esters) are quite complementary of organosilicon coupling molecules for the preparation of mesoporous hybrid organic-inorganic materials by sol-gel processing or surface modification, because of their low cost and great variety. Noticeably, some polyphosphonic acids are of very wide sources and low cost, which·have already been used as the main components in industrial detergents, such as1-hydroxy ethylidene-1,1-diphosphonic acid (HEDP), amino tri(methylene phosphonic acid)(ATMP), ethylenediamine tetra(methylene phosphonic acid)(EDTMP) and diethylenetriamine penta(methylene phosphonic acid)(DTPMP).However, the reported mesoporous metal phosphonate materials still suffer from poorly structured mesopores with low surface area and pore volume, low crystallinity and stability, etc. There are some examples of ordered mesoporous aluminum phosphonates, which were prepared only by alkyl bridged diphosphonates. The ordered mesoporous metal sulfonates were scarcely reported. Therefore, it is important and challenge for the synthesis and application of ordered metal phosphonates and sulfonates with various organic functional groups and metal centers. The following results and conclusions have been obtained in this dissertation:1. Mesostructure adjustment. Hexagonal mesoporous titanium phosphonate materials were synthesized by an autoclaving process combined with the evaporation-induced self-assembly (EISA) strategy, with the assistance of surfactant Brij56(C16EO10). EDTMP was used as the coupling molecule. The organophosphonate groups were homogeneously incorporated in the network of the mesoporous solids. The obtained materials were thermally stable up to450℃. The hybrid materials could be used as not only efficient adsorbents for heavy metal ions in the water but also as outstanding photocatalysts. By changing the molar ratios of adding raw materials, namely, Ti/P molar ratio and CTAB/Ti molar ratio, cubic mesoporous titanium phosphonates could also be synthesized, which exhibited multifunctionality in photocatalysis and adsorption;2. Post-treatments. Ordered mesoporous titanium phosphonates were prepared using HEDP as the anchoring molecule. The alkyl hydroxyl groups of HEDP made it possible for the further functionalization by ClSO3H treatment. The modified materials acted not only an ion exchanger with large ion exchange capacity but also a strong acid catalyst possible for some room-temperature reactions. Moreover, the organic-inorganic hybrids were proved to be molded and incised into various shapes facilely, making them practical materials for industrial scale manufacture. The homogeneous integrity of organic groups inside the hybrid framework also allowed Cu2+ions extensively coordinated with these organic ligands. And further calcination of the Cu2+ion-dispersed matrix resulted in the highly dispersed CuO active components on the pore surface of mesoporous titanium phosphonates, making them promising catalysts for low-temperature CO oxidation;3. Crystalline mesopore walls. Ordered hexagonal mesoporous metal (Ti, Zr, V, Al) phosphonate materials with microporous crystalline walls were synthesized through a microwave assisted procedure by using triblock copolymer F127as the template. Corresponding metal chlorides and EDTMP were chosen as the inorganic precursors and the coupling molecule, respectively. The metal phosphonate materials could be thermally stable up to around450℃with the pore structure and hybrid framework well preserved. For the first time, the mesoporous hybrid materials were employed as the stationary phase in open tubular capillary electrochromatography (OTCEC) technique for the separation of various substances including acidic, basic and neutral compounds, showing good selectivity and reproducibility;4. Mesoporous sulfonates. Ordered hexagonal mesoporous titanium tetrasulfonate materials were synthesized through a hydrothermal process with the assistance of surfactant F127, by using the copper(II) phthalocyanine-tetrasulfonic acid tetrasodium salt (CuPcS4) as coupling molecules. A novel model of isolated dye centers surrounded by semiconductor oligomers was set, which could effectively suppress the aggregation of dye molecules. The synthesized materials exhibited a photoelectric conversion efficiency of0.53%. Ordered mesoporous metal-organic frameworks were prepared by a bottom-up strategy through the simple self-assembly of metal sulfonate ligands, metal ions and block coplymer template F127, with the aid of crown ether to control the coordination rate between metal ions and sulfonate ligands. The synthesized materials have high stability upon thermal treatment to300℃and guest molecule adsorption.