Ternary Eutectic Assembly Synthesis Of Ordered Mesoporous Polymer - Oxide Nano-composite Materials And Carbon Materials

The synthesis and assembly of mesostructured materials represent an exciting direction in the research fields of materials science, chemistry, physics and life science. During the past decades, mesoporous inorganic materials with different mesostructures have been synthesized by organic-inorganic self-assembly, wherein Si(OR)₄, R_xSi(OR')_4-x and MC1_x or their mixture are used as inorganic precursors and amphiphilic supramolecule is used as a template. Recently, mesoporous polymers (carbon) with open frameworks have been developed by organic-organic self-assembly of triblock copolymers with resols. However, up to now, the prepared materials are far from diversified in single compositions. More and more attention focuses on organizing muti-functional (organic, inorganic and biologic) building blocks into integrate nanocomposites, which have remarkable and complementary properties. Moreover, confined-space effects inside the nanospace of mesostructures would certainly modify the unique chemical behaviors. The research presented in this thesis is aimed to present a simple, low-costing and easily reproducible approach to prepare mesoporous nanocomposite, enriching the compositions and to take a further step to exploit their applications, such as electronics and magnetics and energy storage.This thesis is based on an "evaporation induced triconstituent co-assembly method", which was a combination of organic-inorganic self-assembly to ordered mesoporous silicates and organic-organic self-assembly to ordered mesoporous polymers. It consists of two parts: (1) Synthesis of ordered mesoporous carbon-silica and carbon-metal oxide nanocomposites by the evaporation induced triconstituent co-assembly method. And ordered mesoporous carbons can be derived with large pore size, pore volume and high surface area. (2) Studies on the applications of the resultant mesoporous carbons in energy storage and mesoporous carbon-titania nanocomposites in photocatalysis of RhB.In chapter 2, highly ordered mesoporous polymer-silica and carbon-silica nanocomposites with interpenetrating networks have been successfully synthesized by the evaporation-induced triconstituent co-assembly method, wherein soluble resol polymer is used as an organic precursor, prehydrolyzed TEOS is used as an inorganic precursor, and triblock copolymer F127 is used as a template. It is proposed for the first time that ordered mesoporous nanocomposites have "reinforced concrete"-structured frameworks. By adjusting the initial mass ratios of TEOS to resol, we determined the obtained nanocomposites possess continuous composition with the ratios ranging from zero to infinity for the two constituents that are "homogeneously" dispersed inside the pore walls. The presence of silicates in nanocomposites dramatically inhibits framework shrinkage during the calcination, resulting in highly ordered large-pore mesoporous carbon-silica nanocomposites. Combustion in air or etching in HF solution can remove carbon or silica from the carbonsilica nanocomposites and yield ordered mesoporous pure silica or carbon frameworks. The process generates plenty of small pores in carbon or/and silica pore walls. Ordered mesoporous carbons can then be obtained with large pore sizes of 6．7 nm, pore volumes of 2．0 cm³/g, and high surface areas of 2470 m²/g. The pore structures and textures can be controlled by varying the sizes and polymerization degrees of two constituent precursors. Accordingly, by simply tuning the aging time of TEOS, ordered mesoporous carbons with evident bimodal pores at 2．6 and 5．8 nm can be synthesized. Additionally, the synthesis of other topologies of mesostructured nanocomposites has been exploited by using other triblock copolymers, such as P123, F108andB50-6600．In chapter 3, the electrochemical behaviors of ordered mesoporous carbon MP-C-46 (based on chapter 2) in energy storage such as EDLC and lithium battery anode were investigated in detail in comparison with common carbon C-FDU-15, which was obtained by organic-organic self-assembly strategy without the presence of inorganic silicate precursor. In the organic electrolyte of 1 M (C₂H₅) ₄NBF₄/PC, this novel carbon shows a capacitance of 117 F/g, larger than that of other ordered mesoporous carbons that have been reported. The capacitor fabricated by this carbon material shows the rectangular-shape CV curves between 0～3 V over a wide range of scan rates up to 200 mV/s. And in lithium storage, a high specific capacity of about 1048 mAh/g was observed for this carbon at the first cycle. And the charge/discharge process remained at a high reversible capacity level with a good cycle performance. The results show the attractive capabilities of this carbon as a hopeful material in energy storage.In chapter 4, ordered mesoporous carbon-titania nanocomposites with crystalline framework were synthesized by the evaporation-induced triconstituent co-assembly followed by the in-situ crystallization technology. The composition of the nanocomposites can be controlled by adjusting the initial mass ratios of TiCl₄ to resol. The resultant materials possess not only high stability but also high BET surface area and uniform pore size distribution. Specifically, we demonstrate this method for ordered mesoporous crystalline carbon-metal oxides nanocomposites consisting of photocatalycally active nanocrystals and glass-like carbon with strong adsorption ability in the C-TiO₂ system, which show good performance in degradation of Rhodamine B. This approach could be applied to design many other ordered mesoporous crystalline M_xO_y-carbon nanocomposites with functional properties.