| Ordered mesoporous materials, with pore diameter between 2 nm to 50 nm, have drawn researchers interests due to their superb properties including large surface area, uniform and adjustable pore architecture and good mechanical property, which allow a variety of different applications of the mesoporous materials, including catalysis, separation, purification, sensing and energy storage. Researchers have also reported different functionalization strategies of these mesoporous materials to improve the properties, such as improving electrochemical property by heteroatom doping of mesoporous carbon.;One generalized synthetic strategy to synthesize ordered mesoporous materials is soft templating method. The functionalization of these mesoporous materials, such as heteroatom doping, can sometimes to lead ordered porous structure collapse, which is usually due to structure deformation during high temperature treatment. For instance, it is challenging to synthesize ordered mesoporous metal oxide with high crystalline pore wall with soft-templating method, as the growth of the crystals can deform the ordered porous structure. Meanwhile, it is difficult to synthesize ordered mesoporous carbon with high doping level (>10 at%) via soft-templating strategy as well, since the rapid doping reaction at high temperature can lead to ordered structure collapse due to the high vapor pressure generated by doping reactions. Here, we demonstrate several facile synthetic routes to fabricate highly crystalline ordered mesoporous metal oxide and heteroatom doped ordered mesoporous carbon. The application of the nitrogen doped mesoporous carbons in energy storage has also been discussed in this dissertation.;Ordered mesoporous manganese oxide has been reported to be useful in energy storage due to its good electrochemical property, as the transition metal manganese has half-filled 3d orbital, which allows it to donate or accept electrons. However, synthesizing ordered mesoporous manganese oxide with high crystallinity with soft-templating strategy is challenging, as the crystal formation during thermal treatment can deform the ordered porous structure. In this dissertation, the synthesis of ordered mesoporous crystalline manganese oxide films is achieved by microwave-assisted processing to convert manganese carbonate precursor to the oxide, remove the polymeric template and crystallize the Mn3O4, all within 1 min. The microwave heating in this case is primarily induced by the microwave cross-section of the substrate (silicon wafer), together with the absorption of microwaves by manganese oxide to provide local energy, which can provide energy for nucleation/crystallization. Conversely, heating manganese carbonate in a muffle furnace at an analogous surface temperature leads to nanostructure collapse with low crystallinity.;Apart from the synthesis of highly crystalline ordered mesoporous metal oxide, we also demonstrate the functionalization of ordered mesoporous carbon via heteroatom doping. Doped carbons can exhibit enhanced electronic, electrochemical and mechanical properties compared with un-doped carbons. These properties enable their use in applications, such as photovoltaics, catalysis and energy storage. For these applications, nano porosity and high heteroatom doping are generally desirable due to large surface area provided by nanoporous structure and improved properties contributed by heteroatom doping. However, it is challenging to achieve high content of heteroatoms doped carbons as well as maintaining the nanoporous structure. One common method of doping is to use heteroatom containing polymer precursors and carbonizing to synthesize doped carbon, where heteroatom content is limited by the number density of heteroatoms in the precursors. Additionally, during calcination, the nanoporous structure can collapse due to the contraction of pores. In this dissertation, a generalized synthetic strategy for highly doped ordered mesoporous carbons is reported. High concentrations of heteroatom doping in ordered mesoporous carbon is achieved by infiltration of molten dopants into silica reinforced mesoporous crosslinked polymer (phenolic resol) bi-continuous framework and subsequent carbonization. This method is demonstrated to generate ordered mesoporous carbons with high heteroatom content (> 10%) for a wide variety of elements including nitrogen, boron, sulfur and phosphorus, with ordered structure preserved.;With the generalized synthetic route, nitrogen doped multi-shell hollow carbon are fabricated as a matrix material for Lithium-sulfur batteries. The hierarchical hollow structure and chemical decoration (heteroatom doping) of carbon framework can help to suppress polysulfide shuttling, while the macropore provides large pore volume to increase sulfur loading. The nitrogen doped sample shows better cycle stability compared with un-doped sample. Given that this hollow structure with a macropore can increase sulfur loading, the specific capacity is much lower compared with other cases where the pores are much smaller because of the low conductivity of sulfur.;In addition, we also systematically investigate how nitrogen doping influences the rate that molten sulfur can infiltrate and the overall extent of pore filling of highly ordered mesoporous doped carbons via in-situ small angle x-ray scattering (SAXS). Nitrogen doping introduces polar bonds to the carbon framework, which can slow down the diffusion of nonpolar sulfur molecules into porous carbon. These in-situ SAXS measurements provide insights about kinetics information for diffusion of sulfur into mesopores and how the surface chemistry of nitrogen doped carbon can significantly hinder the infiltration of the mesopores by sulfur.;In summary, this dissertation focuses on the functionalization of ordered mesoporous material without losing the ordered structure, as well as the application of nitrogen doped carbon in energy storage. |
