Indiana University-Purdue University Indianapolis (IUPUI) / Three parts consist of my thesis work centered on the synthesis of inorganic phosphates and then metal organic frame work (MOF). The first part is the synthesis of mesoporous chromium phosphates using the room temperature solid state reaction (SSR)approach. One of the major aims of this work is to fill the gap of lacking a low cost, low or zero pollution, easy method to synthesize phosphates. The room temperature solid state reaction has been demonstrated in this work is such a method. Mesoporous chromium phosphates were prepared using the solid state reaction at low temperature using CrCl3.6H2O, and NaH2PO4.2H2O as precursors and the surfactant cetyltrimethyl ammonium bromide (CTAB) as template. The synthesized chromium phosphates were characterized by XRD, EDS, HR-TEM, N2-physisorption, TG-DSC and UV-Vis spectroscopies. The results indicate that chromium phosphate mesophases were formed only at atomic ratios of P/Cr ≥ 1.8. The mesophase for P/Cr = 2.0 phosphate possessed the highest ordering of pore array, with a specific surface area as high as 250.78 m2/g and an average pore size of 3.48nm. The catalytic performance of the chromium phosphates was examined by employing a model reaction, namely the dehydration of isopropanol to propene. The results indicated that all synthesized chromium phosphates exhibited significantly higher isopropanol conversions and propene yields than that synthesized via the conventional precipitation route. The highest propene selectivity (96.43%) at the highest isopropanol conversion (93.10%) has been obtained over the mesoporous chromium phosphate catalyst synthesized with a P/Cr atomic ratio of 2.0. The formation mechanism of the mesoporous chromium phosphate was investigated by FTIR technique.The results show that CTAB template plays a key role in the formation of mesoporous chromium phosphates. Mesoporous lithium manganese phosphates were also successfully synthesized using the same approach of solid state reaction (SSR) at low temperature by using LiC2O3.6H2O, MnCl2.6H2O and NH4H2PO4.2H2O as precursors and the surfactant cetyltrimethyl ammonium bromide (CTAB) as template. The synthesized lithium manganese phosphates were characterized by XRD, EDS, SEM, HR-TEM, N2-physisorption. The results show that the synthesized meoporous lithium manganese phosphates exhibited a high specific surface area (256.63 m2/g) and a narrow pore size distribution. The electrochemical tests of Li-ion batteries were performed and the results show that the charge voltage could increase to be 3.60 V while the first time discharge capacity could be as high as 100 mAh/g. The Nitro-Cu-MOF complexes, a new class of metal organic frameworks, have been successfully synthesized using a conventional thermal reaction. The obtained Nitro-Cu-MOFs have a specific surface area of 576.27 m2/g and a pore volume of 0.32 m3/g.The gas uptake of the obtained Nitro-Cu-MOFs at 60 psi is 68 mg/g (sorbate/sorbent) at 298 K for carbon dioxide, which is much higher than that of the Cu-MOFs, 31 mg/g at 298 K for carbon dioxide.

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Hierarchically structured inorganic materials are everywhere in nature. From unicellular aquatic algae such as diatoms to the bones and/or cartilage that comprise the skeletal systems of vertebrates. Complex mechanisms involving site-specific chemistries and precision kinetics are responsible for the formation of such structures. In the synthetic realm, reproduction of even the most basic hierarchical structure effortlessly produced in nature is difficult. However, through the utilization of self-assembling structures or "templates", such as polymers or amphiphilic surfactants, combined with some favorable interaction between a chosen inorganic, the potential exists to imprint an inorganic material with a morphology dictated via synthetic molecular self-assembly. In doing so, a very basic hierarchical structure is formed on the angstrom and nanometer scales. The work presented herein utilizes the self-assembly of either surfactants or block copolymers with the desired inorganic or inorganic precursor to form templated inorganic structures. Specifically, mesoporous silica spheres and copolymer directed calcium phosphate-polymer composites were formed through the co-assembly of an organic template and a precursor to form the desired mesostructured inorganic. For the case of the mesoporous silica spheres, a silica precursor was mixed with cetyltrimethylammonium bromide and cysteamine, a highly effective biomimetic catalyst for the conversion of alkoxysilanes to silica. Through charge-based interactions between anionic silica species and the micelle-forming cationic surfactant, ordered silica structures resulted. The incorporation of a novel, effective catalyst was found to form highly condensed silica spheres for potential application as catalyst supports or an encapsulation media. Ordered calcium phosphate-polymer composites were formed using two routes. Both routes take advantage of hydrogen bonding and ionic interactions between the calcium and phosphate precursors and the self-assembling copolymer template. Some evidence suggests that the copolymer morphology remained in the composite despite the known tendency for calcium phosphates to form highly elongated crystalline structures with time, as is commonly the case for synthetic hydroxyapatites. Such materials have obvious application as bone grafts and bone coatings due, in part, to the osteoconductive nature of calcium phosphate as well as to the mesoporosity generated through the cooperative assembly of the block copolymer and the inorganic. Future work, including potential experiments to determine osteoconductivity of as-prepared composites, is also presented herein

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This thesis identifies a facile and versatile technique for creating multi-scale porous titania with tunable meso-scale morphology. Three templating approaches were simultaneously utilized in achieving this; namely, soft-templating by template-free self-assembly of an aligned macroporous structure, freeze-casting for the preservation of particle dispersion found in suspension, and hard-templating by the use of cellulose nanocrystals (CNCs) as sacrificial material. A systematic study was conducted wherein three synthesis parameters (water content, alcohol solvent content, and drying method) were varied in the hydrolysis of titanium tetra-isopropoxide (TTIP) by the sol-gel method to determine their contribution to the formation of multi-scale porous titania exhibiting aligned macrochannels and mesoporosity. The optimal synthesis settings for producing multi-scale porous titania were identified as H2O/TTIP molar ratio of 30, without any isopropanol (acting as solvent), and freeze-drying after freezing at -40°C. Subsequently, CNCs were added in various quantities (0-50vol%) to the hydrolysis of TTIP using these optimized settings to achieve more direct and precise control of the final titania meso-structure. Morphological studies revealed that the final titania bodies maintained the formation of macrochannels 1-3 μm in diameter as a result of hydrolysis in excess water in the absence of an organic solvent and exhibited successful templating mutually affected by CNC addition and freeze-casting. Freeze-drying preserved particle dispersion in the colloid suspension, hindering agglomeration otherwise found after oven-drying and enhanced the CNCs' role of disrupting titania aggregation and increasing interconnectivity. Thus, meso-structured multi-scale porous titania was prepared by a combined templating strategy using template-free self-assembly, freeze-casting, and CNC hard-templating. / MS / Titanium dioxide (TiO₂) has been shown to exhibit desirable properties including physical and chemical stability and biocompatibility making it a material of great interest in a variety of fields including pigments and biomedicine. Furthermore, the material’s photocatalytic activity (i.e. ability to absorb light energy to generate usable charge) has led to its implementation in solar cells, in the production of hydrogen as an eco-friendly fuel, and in decontaminating water from organic pollutants. While TiO₂ has shown great promise in these applications, there remains a need to identify a simple strategy to synthesize TiO₂ with a tunable multi-scale porous structure with pores of different sizes and shapes to improve its performance. To this end, a facile and versatile procedure was used to prepare multi-scale porous TiO₂ with tunable morphology. In investigating the effect of water content, alcohol content and drying method on the final morphology, a multi-scale structure was achieved by synthesizing TiO₂ in the absence of an alcohol solvent and within a new moderate range of water content that had not been previously explored. Lacking an effective and easy strategy to further manipulate the multi-scale morphology, this self-assembly technique was modified by incorporating cellulose nanocrystals (CNCs) into the synthesis procedures to further tune the structure on the nanometric scale by altering the final porosity and surface area. The final TiO₂ samples exhibited multi-scale porous structures that could be manipulated by combining the self-assembly and CNC-templating techniques in an adaptable strategy to tailor the TiO₂ morphology for its various uses in photocatalysis and biomedicine.