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Molecular Dynamics (MD) simulations and Quasi Elastic Neutron Scattering (QENS) experiments are used to investigate the dynamics of industrially relevant catalysis reactions. Despite the widespread industrial applications of mesoporous materials there is often little understanding of the dynamical processes within the catalytic pores. In fact the rate limiting step is often the diffusion of the reactants within the pores and so therefore to be able to quantify the diffusion behaviour within these pores, and as bulk liquids to provide a comparison, is important. The dynamics and associated diffusion behaviour of benzene, cyclohexane and cyclohexene both as unconfined liquids and confined in MCM-41 and the catalyst Pt/MCM-41 were obtained. Similar combined MD and QENS studies were carried out on toluene and methylcyclohexane as well as on the three xylene isomers, mesitylene and trifluorobenzene. The time and length scales investigated was on the order of ps to ns and Å in both the MD simulations and QENS experiments. According the QENS experiments the effect of confining a liquid is a decrease in mobility as evidenced by a lower diffusion coefficient for confined liquids. This is true for all five liquids. All confined liquids have similar diffusion coefficients suggesting MCM-41 has the same effect on all liquids. MD simulations were carried out using a three different framework models of MCM-41; a rigid, a semi-flexible and a novel fully flexible to test the effect of framework flexibility on the dynamics of confined sorbates. Both MD and QENS found decreases in the mobility of confined sorbates compared to unconfined. Comparing the bulk diffusion coefficients obtained through QENS experiments and MD simulations shows it is possible to achieve acceptable agreement. The MD simulations underestimate the QENS results for most of the liquids and have larger errors between theory and experiment then the confined systems. The confined systems show much better agreement than the bulk liquids between the MD and QENS studies. In addition the fully flexible MCM-41 framework proved superior in matching the experimental QENS translational diffusion coefficient results. In addition to the dynamical behaviour studied some structural information is obtained through the MD simulations namely distribution functions and probability densities. Through this the effect of confinement on each sorbate is studied. In conclusion the combination of neutron scattering and molecular simulations has provided insight into the dynamics of hydrocarbons both as unconfined bulk liquids and confined in mesoporous materials; namely the mobility of confined liquids is reduced. It is also possible to conclude that framework flexibility is necessary for MD simulations to match experimental results.

The history of ordered mesoporous materials starts with the discovery of MCM-41(Mobil Composition of Matter-41) in 1992 using an organic template as structure directing agent. Mesoporous materials have not only proved to be ideal candidates in various fields like, for example, catalysis but could also be potentially used as a hard template for synthesising other useful mesoporous materials. The aim of this research was to develop industrially feasible and environmentally friendly methods for the preparation of ordered mesoporous materials, to characterise these and to study their applications. The main techniques used for the characterisation of these mesoporous materials were N₂ physisorption, XRD and TEM. In the first part of the study, metal- and halogen-free ordered mesoporous polymer and carbon materials having 2D hexagonal (P6mm) and body centered cubic (Im3̅m) mesostructures were made using a modified two phase method employing alternative polymerisation and condensation catalysts. These materials had high surface area and pore volume and had narrow pore size distributions. Their physical evolution with increasing calcination temperature was examined as were the effects of varying synthesis parameters on the nature of the final mesostructure. The second part of the study was focused on the synthesis of ordered mesoporous ceria using metal- and halogen-free ordered mesoporous carbon materials - made in the first part of the study - as the hard template. The mesoporous ceria having 2D hexagonal arrangement of pores were successfully synthesised using a solid-liquid method which is a solvent free, easy to use and environmentally friendly method. The carbon template calcined at 400 °C was found to be the best template in terms of giving high loading of precursor and giving high quality product. The synthesis of body centered cubic ceria was less successful than hoped due to the small pore openings in this template material. The third part of study involved the preparation of mesoporous carbon supported Pd catalysts and their use in the hydrodechlorination of trichloromethane (TCM). The results were very promising, and 100 % conversions were obtained at 175 °C with high selectivity to alkanes and low selectivity to intermediate chlorinated products.

The development of mesoporous titania (meso-TiO2) films is a considerable research goal in the field of mesoporous material development due to their proven applicability in solar cells and phtocatalysts. In this work, the meso-TiO2 films were fabricated through different methods and these home-made titania structures were applied in DSSCs and photocatalysts. Meso-TiO2 powders were first prepared from ethanol/water or ethanol solvent. The meso-TiO2 made from the ethanol/water solvent did not have an ordered mesostructure, but that made from ethanol solvent had 2D-hexagonal mesostructure. Films were prepared by adding ordered meso-TiO2 particles into paste formulations of P25 nanoparticles with weight proportion ranging from 0 to 100%. These were used to form films by doctor blading, and the influence of paste composition on film structure, morphology, porosity, optical properties and cell performance were investigated. Secondly, ordered meso-TiO2 films were fabricated by dip coating from aqueous or ethanol solvent. Both films had cubic mesostructures, but the film coated from aqueous solvent was not uniform. The film formed from ethanol solvent was doped with sulphur. The effects of doping on the mesostructure, morphology, structure, optical properties and photocatalytic activity were studied. The thickness of films was increased by repeated coating. The number of layers had an influence on the mesostructure, morphology, optical properties and cell performance when these films were applied in DSSCs Finally, a novel method was adopted to prepared meso-TiO2 films. Molecular titania precursors or titania colloidal seeds were used as the titania source. Both of them can be used to prepare free-standing hybrid films at air-water interface by a self-assembly method, however the one synthesised from the molecular titania precursor did not contain very much titania and became a powder after calcination. In contrast, after calcination, the films formed from the colloidal titania solution remained intact, and were composed of mixtures of TiO2 nanoparticles and nanowires with mesopores arising from interparticle porosity. These films were applied in DSSCs. This interfacial method was also successfully extended to prepare free-standing ZnO films from a molecular precursor. After calcination, the free-standing ZnO films were found to be composed of rough spheres formed by flocculation of smaller nanoparticles.

Ordered mesoporous materials have attracted much attention recently for use in a wide range of applications. The oxidising materials, ceria (CeO₂) and CGO (Ce₀.₉Gd₀.₁O[subscript(2-δ)]) have both been synthesised with ordered mesopores, but a method for the simple fabrication of these materials in high yields with crystalline pore walls has not yet been reported in the literature. This thesis details the development of the vacuum impregnation method for the synthesis of ordered mesoporous materials with emphasis on ceria and CGO. Using the vacuum impregnation method both materials were successfully prepared. The materials exhibited the porous single crystal morphology in high yields, with unusual crystallographic features. Nitrogen physisorption, transmission electron microscopy (TEM), TEM tomography and temperature programmed studies were employed. Temperature programmed studies showed the materials to be catalytically active at lower temperatures than traditionally-prepared ceria. Photovoltaic studies showed that the materials exhibited efficient exciton quenching. The observation of nanowire extrusion during the synthetic procedure assisted in the postulation of a mechanism for product formation in the vacuum impregnation method. The vacuum impregnation method was subsequently shown to be applicable to the synthesis of other materials, with encouraging results presented for ordered mesoporous carbon and Zr₀.₈₄Y₀.₁₆O[subscript(2-δ)]. The syntheses of ordered mesoporous La₀.₈₅Sr₀.₁₅GaO[subscript(3-δ)] and La₀.₇₆Sr₀.₁₉CoO[subscript(3-δ)] were unsuccessful.

The experimental data and results demonstrated here illustrate the preparation and application of mesoporous metal oxides in energy storage, adsorption, and catalysis. First, a new method of controlling the pore size and wall thickness of mesoporous silica was developed by controlling the calcination temperature. A series of such silica were used as hard templates to prepare the mesoporous metal oxide Co₃O₄. Using other methods, such as varying the silica template hydrothermal treatment temperature, using colloid silica, varying the materials ratio etc., a series of mesoporous β-MnO₂ with different pore size and wall thickness were prepared. By using these materials it has been possible to explore the influence of pore size and wall thickness on the rate of lithium intercalation into mesoporous electrode. There is intense interest in lithium intercalation into titanates due to their potential advantages (safety, rate) replacing graphite for new generation Li-ion battery. After the preparation of an ordered 3D mesoporous anatase the lithium intercalation as anode material has been investigated. To the best of our knowledge, there are no reports of ordered crystalline mesoporous metal oxides with microporous walls. Here, for the first time, the preparation and characterization of three dimensional ordered crystalline mesoporous α-MnO₂ with microporous wall was described, in which K+ and KIT-6 mesoporous silica act to template the micropores and mesopores, respectively. It was used as a cathode material for Li-ion battery. Its adsorption behavior and magnetic property was also surveyed. Following this we described the preparation and characterization of mesoporous CuO and reduced Cu[subscript(x)]O, and demonstrated their application in NO adsorption and delivery. Finally a series of crystalline mesoporous metal oxides were prepared and evaluated as catalysts for the CO oxidation.

By replacing the intercalation electrode with a porous electrode and allowing lithium to react directly with O₂ from the air, the new rechargeable Li/O₂ battery system was studied. The porous cathode is comprised of carbon, catalyst and binder. The effect of every component was investigated. The catalyst was believed to play an important role in the performance of the electrode. A number of potential materials have been examined as the catalyst for the O₂ electrode. It suggests that the nature of the catalyst is a key factor controlling the performance of the O₂ electrode. Several catalysts based on first row transition metal oxides each with three different morphologies, bulk, nanoparticulate and mesoporous were studied. The influence of the morphology on the discharge and charge voltage, discharge capacity and cyclability were examined. Among all the catalysts studied, α-MnO₂ nanowires was found to be the best candidate. The reversible capacities of 3000 mAhg⁻¹(normalised by the mass of carbon) or 505 mAhg⁻¹ (based on the total mass of cathode + O₂ ) was obtained. Some of other factors, such as type of carbon, type of binder, type of electrolyte, the construction of cathode and the modification of the catalyst were also investigated, even just in the early stage. Capacity fading during cycling is the main problem in all the cases. A number of experiments were carried out to understand and attempt to avoid the fading problem. After successful synthesis of mesoporous α-Fe₂O₃ with unique properties (by Jiao et al.), the application of these materials in conventional Li battery was studied. Mesoporous α-Fe₂O₃ with ordered walls, mesoporous α-Fe₂O₃ with disordered walls and Fe₂O₃ nanoparticles were examined. It was also applied to examine the different factors that influence the rate of conversion electrodes, i.e., Li⁺ and e⁻ transport to and within the particles, as well as the rate of the two-phase reaction, demonstrating that for this conversion reaction electron transport to and within the particles is paramount.

Mesoporous monocrystalline metal oxides (e.g. Co₃O₄, Cr₂O₃, NiO, CeO₂, In₂O₃ and WO₃) templated by SBA-15 or KIT-6 were synthesised successfully by using a simple solvent-free approach, the so-called solid-liquid method, which was the principal development of methodology in this project. A metal-containing precursor, whose melting point is lower than its decomposition temperature, was directly ground with a mesoporous silica and impregnated into the pores of the silica template after melting when the temperature was increased above its melting point. The liquid precursor then decomposed to form metal oxide inside the silica pores when the temperature was further increased to its decomposition temperature and crystallization temperature of the oxide. The structural characterisations of these porous metal oxides were performed by using TEM, XRD and N₂ adsorption/desorption techniques. The solid-liquid method is convenient and solvent-free. On the other hand, its limitation is that the precursor must have a melting point lower than its decomposition temperature. A novel porous single crystal of rutile TiO₂ as well as anatase nanocrystal-silica composite was also synthesised successfully for the first time using SBA-15 and KIT-6 as templates. These materials have interesting properties of proton conductivity, Li insertion and photoactivity. Likewise, the characterisation of porous TiO₂ was achieved by using XRD, TEM, SAED and N₂ adsorption/desorption. The residual SiO₂ component in porous TiO₂ was detected by using the EDX technique. Porous cubic metal oxides of Co₃O₄, NiO, CeO₂ and In₂O₃ were prepared using novel mesoporous silicas FDU-12 and SBA-16, which contain spherical nanocavities linked together by smaller windows. These porous materials have larger surface areas than those templated by SBA-15 and KIT-6. Unlike the cubic metal oxides, syntheses of porous crystals of non-cubic metal oxides such as rhombohedral Cr₂O₃, Fe₂O₃ and hexagonal TiO₂, WO₃ were not successful when using cage-containing mesoporous silicas as templates. The three-dimensional arrangements of nanospheres in porous crystals of cubic oxides mentioned above were observed by TEM and the corresponding larger surface areas were confirmed by N₂ adsorption/desorption technique. Additionally, fabrication of porous crystals of other metal oxides such as MgO, ZnO and ZrO₂ were unsuccessful by using either mesoporous silicas or mesoporous carbons as templates. Possible drawbacks of using mesoporous silica and carbon as templates were discussed.

A range of mesoporous materials based on SBA-15, KIT-6 and FDU-12 have been prepared using neutral block copolymers Pluronic P123 and F127 and characterised using methods including electron microscopy and nitrogen adsorption. Typically the materials have a hexagonal (p6mm) or cubic (Fm3m and Ia-3d) symmetry and pore geometry and are rendered porous by either calcination or solvent extraction. Organic functional groups were incorporated into the silica walls of the materials by co-condensation in the form of propyl thiols and additives in the form of alkanes were added to control pore size and geometry. The effects of temperature, additives, organic functionalisation, synthesis time and sol-gel composition were investigated and the resulting materials were tested as supports for protein adsorption, enzyme immobilisation, and drug delivery. Two FDU-12 materials of differing entrance and cavity sizes were used to adsorb a range of proteins with molecular weight 17 to 160 kDa to determine if there was a size exclusion effect. It was seen that the larger pore material was able to adsorb proteins of a larger size (molecular weight 105 kDa) and an exclusion effect was observed when the dimension of the proteins became too great (larger than 130 kDa). There was no clear trend for the smaller pore material where each protein was adsorbed to some extent by the material but apart from the smallest protein, myoglobin, mainly on the surface and not within the pores. The adsorption of the lipase B from Candida Antartica, CALB, was studied on a range of mesoporous supports with their templates removed by either calcination or extraction. The effect of pore size and functionalisation was investigated in terms of maximum loading and rate of loading. By functionalising the KIT-6 material the maximum loading of CALB was reduced from 45.5 to 32 mg/g whereas functionalising the FDU-12 material increased the maximum from 33 to 42.5 mg/g. The activity of the immobilised CALB was measured by enantioselective transesterification of (R)-1-phenylethanol in methyltetrabutyl ether (MTBE). The effect of loading, surface functionalisation and reusability in organic media were investigated. Functionalisation with propyl thiol was seen to increase the rate of conversion after 30 minutes for both KIT-6 and FDU-12 materials. Selected FDU-12 and KIT-6 materials with window sizes from 6 to 12 nm and with and without functionalisation were used to carry out a drug release study using Bovine serum albumin (BSA). BSA was loaded onto the material and the uptake quantified using nitrogen adsorption, elemental analysis, and thermogravimetric analysis. The release of BSA into simulated body fluid at 37 ºC was measured using HPLC. Functionalisation was seen to have little effect. The type of cubic morphology controlled the rate at which the BSA was released. The KIT-6 3D channel material exhibited a burst release initially followed by a steady release of BSA whereas the mesocage FDU-12 material had a slower and more linear release profile, closer to that desired.

A range of mesoporous materials based on SBA-15 have been prepared and characterised. The materials were templated by neutral block copolymer P123, and typically have a hexagonal (p6mm) pore structure, with high surface areas and narrow pore size distributions. The removal of the surfactant template by calcination and solvent extraction has been investigated. The aqueous stability of this material, and the hydrolysis of the surface was studied. Organic functional groups were incorporated into the silica surface by co-condensation, or by post synthesis grafting. A range of functional groups were incorporated, including amine, carboxy, allyl and thiol groups. The pore size of the materials was controlled by the addition of trimethoxybenzene during synthesis, which significantly increased the pore size and uptake capacity of the materials. The adsorption of CALB by SBA-15 was investigated, with support materials extracted by calcination or solvent extraction. Rapid uptake at high loading was observed, with a maximum loading of 450 mg g-1 measured. The leaching of the enzyme from the support was investigated, and found to be high with unfunctionalised supports. The leaching from functionalised supports incorporating sulfur groups was significantly reduced. The activity of the immobilised CALB was measured by tributyrin hydrolysis in aqueous media, and by enantioselective transesterification of (R)-1-phenylethanol in organic media. The effect of surface functionalisation for reusability and thermal stability in aqueous systems was investigated. Preliminary studies of supported CALB for dynamic kinetic resolution were carried out, with an investigation of acidic zeolites and a mesoporous supported catalyst for 1-phenylethanol racemisation. The encapsulation of immobilised CALB was investigated, and the activity and reusability of these systems studied.

The creation of next-generation functional materials will require fine control of nanoscale surface characteristics. Two common approaches to this problem are the formation of nanoparticles and the synthesis of mesoporous materials. By incorporating nanoscale structural features, not only can a greater proportion of the material be devoted to active surface area, but properties can also emerge that are absent in the corresponding bulk material. For example, metals can be miscible on the nanoscale despite being immiscible in the bulk, and restrictive mesopores can lead to increased catalytic selectivity. Mesoporous LaMnO₃-SiO₂ composites were synthesized by several different nanocasting routes using SBA-15 silica as the hard template. The final composites were stable in refluxing NaOH solution, indicating encapsulation of the remaining SiO₂ in each case, although the exact structure of the composites depended on the solvent mixture in which they were prepared. All three composites displayed respectable pseudocapacitative capabilities, with normalized specific capacitances over 200 F g⁻¹. The next project revolved around the synthesis of RhPd alloy nanoparticles and the examination of their hydrogenation activity. RhPd alloy nanoparticles were synthesized using both microwave and conventional heating and a range of reaction times. Application of these particles to the hydrogenation of cyclohexene revealed that particles synthesized at very short reaction times showed comparable reactivity to particles that had been heated for hours longer. In addition, the empirical finding that RhPd alloys have a hydrogenation activity between those of the two pure metals was further supported by DFT calculations. Third, RhPdAu alloy nanoparticles were synthesized for use as hydrogenation catalysts. Tuning the exact composition of this alloy system is expected to influence the catalysts’ activity, and the inclusion of gold may promote selective hydrogenation of the carbonyl bond in unsaturated aldehydes. A series of alloy compositions has been successfully synthesized, but their catalytic properties remain untested. Finally, Rh nanoparticles supported on Co₃O₄ are also being studied for this selective hydrogenation of unsaturated aldehydes. Preliminary results suggest the mesoporosity of the support may play a crucial role in controlling the orientation of the substrate molecule, and therefore the selectivity toward the desired product.

Macroscopic alignment of block copolymer domains in thin films is desired for many applications, such as cell responsive surfaces or optical polarizers. Alignment generally requires specialized tools that apply external fields, shear force gradient, or produce topological patterned substrates. This requirement limits the broad academic application of aligned BCPs. Here, we describe a simple modification of commonly utilized solvent vapor annealing (SVA) process for macroscopic alignment of BCPs. Adhering a flat, crosslinked elastomer pad to the BCP film leads to differential swelling between the elastomer pad and BCP to produce a shear force that aligns the ordered BCP domains. The role of elastomer properties, solvent quality, drying rate and degree of segregation of the block copolymer will be discussed to provide generalized rules for alignment with this technique. By proper selection of the BCP and functional precursors, functional nanopatterns can be obtained such as silica nanolines, rhombic arrays and highly aligned porous carbon films. Roll-to-roll (R2R) processing enables the rapid fabrication of large-area sheets of cooperatively assembled materials for production of mesoporous materials. Evaporation induced self-assembly of a nonionic surfactant with sol-gel precursors and phenolic resin oligomers produces highly ordered mesostructures for a variety of chemistries including silica, carbon, tin oxide and titania. The cast film can be easily delaminated from the carrier substrate after crosslinking the resol to produce meter-long self-assembled sheets. The pore textures including surface areas, pore size and pore volume can be effectively controlled by tuning the processing conditions. Moreover, inclusion of dopants in the multi-component solution for cooperative assembly leads to additional functionality of these mesoporous materials. The performance of as-synthesized materials as electrodes for batteries or for dye removal will also be discussed in this dissertation.

Mezoporowate nanocząsteczki krzemionkowe są stosunkowo nowymi związkami. Od momentu pierwszej syntezy ich potencjalne zastosowanie upatrywano w unikatowych właściwościach, które wynikają z ich struktury. Krzemionki posiadają mezopory o jednolitej i regularnej wielkości oraz bardzo dużej objętości. Ponadto nanocząsteczki te charakteryzują się regularną wielkością oraz bardzo dużą powierzchnią zewnętrzną. Ich silną bioaktywność wynika z obecności licznych grup funkcyjnych na zewnętrznej i wewnętrznej powierzchni. Krzemionki mogą być w łatwy sposób modyfikowane. Umożliwia to dołączanie organicznych i nieorganicznych grup, łączników czy całych cząsteczek, które pozwalają osiągnąć pożądane właściwości krzemionek. Szeroka charakterystyka materiałów mezoporowatych przyczynia się do ich lepszego poznania, określenia ich potencjalnego użycia w naukach biomedycznych i wyselekcjonowania najlepszych materiałów do poszczególnych zastosowań. Niniejsza praca jest charakterystyką czterech typów mezoporowatych nanocząsteczek krzemionkowych: SBA-OH, SBA-SH, SBA-NH2 oraz SBA-COOH. Nanocząsteczki te różnią się miedzy sobą grupami powierzchniowymi oraz modyfikacjami organicznymi, a także wielkością porów. Krzemionki te zostały także porównane z krzemionką amorficzną. Celem niniejszej rozprawy było określenie czy i w jakim stopniu modyfikacje organiczne oraz grupy funkcyjne wpływają na właściwości krzemionek. Badano wpływ mezoporowatych nanocząsteczek na czerwone komórki krwi poprzez ocenę stopnia hemolizy w próbkach erytrocytów oraz erytrocytów w obecności albuminy surowicy człowieka (HSA). Określono zdolność krzemionek do adsorbowania hemoglobiny (Hb). Badano również cytotoksyczność krzemionek względem linii komórkowej prawidłowej (B14) oraz linii nowotworowych (HL60, 1301 i BRL) wykorzystując testy MTT oraz AlamarBlue. Kolejnym etapem były badania oddziaływania mezoporowatych krzemionek z białkiem – albuminą surowicy ludzkiej z wykorzystaniem dichroizmu kołowego, gaszenia fluorescencji HSA oraz wolnego L-tryptofanu, a także oznaczenia adsorpcji albuminy. Ostatnim etapem było poznanie właściwości powierzchni krzemionek poprzez badanie rozmiaru porów, ich objętości oraz powierzchni właściwej nanocząsteczek. Ponadto zbadano potencjał zeta oraz za pomocą mikroskopu sił atomowych AFM oraz transmisyjnego mikroskopu elektronowego TEM obserwowano morfologię krzemionek. Wszystkie badania oraz porównanie krzemionek mezoporowatych i krzemionki amorficznej pozwoliły stwierdzić, iż zarówno struktura, jak i modyfikacje organiczne oraz przyłączanie grup powierzchniowych wpływają na właściwości tych materiałów. Znacznie niższa hemo- i cytotoksyczność, a także oddziaływanie z białkiem ukazują przewagę mezoporowatych krzemionek nad krzemionką amorficzną.

Controlling the structure of inorganic materials on the mesoscale (2-50 nm) is desirable for many applications and can influence the materials' properties and performance in devices. Amphiphilic block copolymers (BCPs) have been used extensively to structure-direct transition metal oxides, controlling their mesoscale morphology. By selectively incorporating metal oxide precursors into one block of the BCP and removing the BCP through thermal decomposition, ordered mesoporous metal oxides with well-defined mesoscale morphologies can be achieved that are interesting, e.g. for energy conversion and storage applications. This dissertation reports on the amphiphilic block terpolymer poly(isoprene)-blockpoly(styrene)-block-poly(ethylene oxide) used in combination with sol-gel metal oxide precursors to generate ordered three-dimensionally (3D) mesoporous metal oxides. 3D cocontinuous cubic network structures such as the alternating gyroid are particularly interesting for energy applications due to their chirality, co-continuity, and high porosity. In particular, the high porosity and mesoscale dimensions can facilitate rapid diffusion of gases/liquids, but limit solid state diffusion lengths in the inorganic structure during chemical conversions of the oxides, e.g. nitriding. Freestanding gyroidal mesoporous metal oxides can be further processed into gyroidal mesoporous metal nitrides by heating under flowing ammonia gas. Transition metal nitrides are of interest due to their electrical conductivity and electrochemical stability. The development of a synthesis for 3D ordered mesoporous nitrides opens paths for studying the effects of welldefined block copolymer mesostructures on superconductivity, an exciting new field.

The depletion of fossil fuels and the climate change have spurred tremendous research interest in the development of electrochemical technologies such as water splitting for conversion and storage of electricity produced from renewable sources such as solar and wind. However, the sluggish kinetics of the anodic oxygen evolution reaction (OER) in water splitting remains a major challenge for widespread application of the technology. Catalysts play a key role in reducing the OER energy barrier, and improving the overall efficiency. Currently, the most efficient OER catalysts are noble-metal based materials including RuO2 and IrO2. However, these noble metals are expensive and the supply is unsustainable, and is not suitable for large-scale application. Therefore, the development of highly efficient and cost-effective electrocatalysts is highly demanded for substitution of these noble metal-based catalysts. In this thesis, two novel non-precious metal-based mesoporous multi-metallic catalysts are developed for enhanced OER. Specifically, i) Fe embedded mesoporous Co3O4 (Fe/mCo3O4) is prepared via hard-template direct nanocasting method for OER. Attributed to an unusual synergistic effect between mCo3O4 and Fe, Fe/mCo3O4 is capable of delivering current density of 30 mA cm-2 at the overpotential of 440 mV showing higher catalytic activity than conventional Co3O4 nanoparticles. ii) A freestanding, hierarchically structured 3D electrode comprising of topmost mesoporous NiFe nanosheets, in-between nanoporous NiCo2O4 nanoflakes and bottom macroporous Ni foam (NiFe/NiCo2O4/NF) is achieved for highly efficient OER at high current densities. The electrode can deliver a current density of 1200 mA cm-2 at 1.57 V vs. RHE, which is comparable to the benchmark IrO2 and RuO2 catalysts. The physical properties of the catalysts are characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and N2 adsorption-desorption isotherms. The electrochemical performances are evaluated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry. The results obtained in this thesis highlight that by proper design of nanoporous structures of the catalysts and smart utilisation of metal-metal synergistic interactions, multi-transition metal-based catalysts offer promising substitutes for the noble metal-based catalysts for use in commercial water splitting systems.

Model materials consisting of metal nanoparticles loaded onto oxide supports were synthesized, characterized, and investigated in a number of catalytic chemical reactions. By varying the size, shape, and composition of nanoparticle, as well as the material used to support the nanoparticles, it was found that small changes to the catalyst can have enormous changes to the reaction activity and selectivity. Investigation of these carefully synthesized catalysts via in situ characterization, and reaction studies, leads to a deeper understanding of the molecular level parameters that govern catalysis. Through study of the properties of the nanoparticles it was discovered that nanoparticle size and shape have a dominant role in the chemoselective catalysis of furfural over platinum nanoparticles. When vapor phase furfural and hydrogen gas were passed over Pt nanoparticles ranging in size from 1.5 to 7.1 nm, the catalytic selectivity was found to be dominated by the size of the nanoparticle. Large nanoparticles promoted hydrogenation of furfural to furfuryl alcohol, while smaller nanoparticles favored decarbonylation to furan. The same size specific selectivity was found in the hydrogenative reforming (the transformation of hydrocarbons to branched isomers) of C6 hydrocarbons, in which Pt nanoparticle size controls isomerization selectivity. Methylcyclopentane was found to be extremely size dependent at lower temperatures (553 K). It was found that smaller sized nanoparticles favored isomer formation, while larger sizes catalyzed the aromatization reaction more efficiently. n-hexane was found to be much less dependent on particle size, but still showed an increase in isomerization with small particles over larger sized Pt nanoparticles. The composition of PtxRh1-x bimetallic nanoparticles was also studied. These catalysts were characterized under hexane reforming conditions with Ambient Pressure X-ray Photoelectron Spectroscopy (AP-XPS), in order to find the actual surface atomic composition under real catalytic working conditions. By using AP-XPS and catalytic data in tandem, it was found that an optimum Rh loading occurred when the surface ensemble statistically favored one Rh atom surrounded by Pt atoms. By utilizing different oxide materials for catalytic supports the flow of charge can play a role in the reaction at the surface or interface in a phenomenon known as the strong metal-support interaction (SMSI). When Pt nanoparticles were loaded onto mesoporous supports made of Co3O4, NiO, MnO2, Fe2O3, and CeO2 it was found that their activity for carbon monoxide oxidation was greatly enhanced relative to the support alone or Pt loaded onto inert mesoporous silica. This finding demonstrates that the interface of the metallic Pt nanoparticle and the oxide support is able to produce turnovers that are orders of magnitude higher than the two materials separately. When the same type of experiments were investigated with n-hexane as the reactant and macroporous Al2O3, TiO2, Nb2O5, Ta2O5, and ZrO2 were utilized as supports, it was found that the reaction selectivity was greatly altered depending on the catalytic support material. TiO2, Nb2O5, and Ta2O5 (all of which are strong Lewis acids) were found to be much more selective for isomer production than the standard SiO2 mesoporous silica supported Pt nanoparticle catalyst. Finally, an acidified mesoporous silica material was utilized as the support. This material was synthesized by using AlCl3 to modify the surface of mesoporous silica. This support was found to have no activity for hexane isomerization alone. However, when Pt nanoparticles were supported on the material, the activity and isomer selectivity in hexane reforming was increased several orders of magnitude as compared to the same nanoparticles supported on unmodified mesoporous silica. This dissertation builds on the existing knowledge of known concepts in catalysis science such as structure sensitive reactions, the metal-support interaction, and acid-base chemistry. The results show how small changes in the active sites of a catalyst can create large changes in the catalytic chemistry. This research demonstrates how careful material control, characterization and reaction study can help to elucidate the molecular level components necessary to design efficient catalysts.

In the present study, we report the synthesis of thermally stable mesoporous gallium oxide and novel gallium-niobium mixed oxides employing Evaporation Induced Self-Assembly (EISA), Self-Assembly Hydrothermal-Assisted (SAHA) and Self-Assembly Microwave-Assisted approaches. These methods offer the possibility to synthesize thermally stable mesoporous oxides with controlled morphological, textural and structural properties. EISA led to partially crystalline meso porous gallium oxide phases displaying unimodal pore size distribution in the ~2-5 nm range and surface areas as high as 300 m2/g. SAHA led to nanocrystalline mesoporous uniform micron-sized gallium oxide spheres (~0.3-6.5 11m) with narrow size distribution displaying cubic spinel type structure. These mesophases displayed surface areas as high as 220 m2/g and unimodal pore-size distribution in the 5-15 nm range. Microwave-assisted approach led to the formation of nanocrystalline mesoporous gallium oxide phases at low reaction temperature (l30°C) and short reaction times (~15-120 min). Novel semicrystalline mesoporous Gallium-Niobium mixed oxide phases were prepared via Self-Assembly Hydrothermal-Assisted (SAHA) method. This method led to the formation of uniform ~ 0.3-2 11m micron-sized mesoporous mixed gallium-niobium oxide spheres with narrow size distribution displaying surface areas as high as 360 m2/g and unimodal pore size distribution in the 3-6 nm range. Due to their high surface areas, tunability of pore sizes and their acidic nature these single phase and mixed mesoporous gallium-niobium oxides were employed as catalysts in the epoxidation of cyclooctene and isomerization of methyl oleate. For the epoxidation of cyclooctene to epoxycyclooctane carried out at 60°C the mesoporous gallium oxide displayed 100% selectivity towards epoxide with the conversion of cyclooctene in the 4 to 16% range. As the reaction temperature was increased to 80°C, an increase in the cyclooctene conversion was observed. The highest cyclooctene conversion observed was ~52% with a selectivity of 83% toward the epoxide. A clear correlation was observed between the cyclooctene conversion and gallium oxide particle size at both reaction conditions. Agglomerate size between 2-3 11m led to higher cyclooctene conversion, whereas the agglomerate sizes between 4.5-7.5 11m led to lower cyclooctene conversions. For the isomerisation of methyl oleate, highest conversion of 57% with the selectivity of 86% and yield of ~50% was observed over a sample with gallium-niobium composition of 0.3:0.7 wt%. The superior catalytic performance of the gallium-niobium mixed oxide was attributed to its high acidity, crystallinity and mesoporosity.

The design of nanoparticles in mesoporous supports is explored through synthetic strategies of electrophoretic deposition and electroless deposition with application towards energy storage. Electrophoretic deposition of nanoparticles into a mesoporous thin film is examined using charged nanocrystals in a low-permittivity solvent. To provide a basis for the deposition, the mechanism of particle charging in a low-permittivity solvent was studied. Dispersions of carbon black particles in toluene with an anionic surfactant were characterized using differential-phase optical coherence tomography with close electrode spacing to measure the electrophoretic mobility. The particle charge in concentrated dispersions was found to decrease as a function of increasing surfactant concentration. Partitioning of cations between the surfactant-laden particle surface and micelle cores in the double-layer was found to govern the dynamics of particle charging. Subsequently, charged Au nanocrystals were deposited by electrophoresis within perpendicular mesochannels of a TiO2 support. High loadings of 21 wt% Au with good dispersion were achieved within the mesoporous TiO2 support using electrophoretic deposition, which would otherwise be inhibited by the weak nanocrystal-support interaction. According to a modified Fokker-Planck equation, the mean penetration depth of a single nanocrystal inside of the perpendicular pores was found to be dependent on the electric field strength, electrophoretic mobility, pore diameter, nanocrystal size, and local deposition rate constant. Nanocomposites for electrochemical capacitors were designed via electroless deposition of redox-active MnO2 in a high surface area mesoporous carbon support. Disordered mesoporous carbon supports with a pore size of ~8 nm were used both in amorphous (AMC) and graphitic (GMC) form, with a ~1000-fold larger conductivity for GMC. High loadings of 30 wt% MnO2 were achieved in the AMC in the form of ~1 nm thick domains, which were highly dispersed throughout the support. Oxidation of the GMC was necessary to facilitate wetting and deposition of the MnO2 precursor in order to achieve high loadings of 35 wt% MnO2 with ~1 nm thickness. High gravimetric MnO2 pseudocapacitances of >500 F/gMnO2 were achieved at low loadings and low scan rate of 2 mV/s for both carbon supports. However, at high scan rates ≥100 mV/s, the MnO2 pseudocapacitance is twofold larger for MnO2/GMC, relative to MnO2/AMC. Sodium ion diffusion throughout both MnO2/AMC and MnO2/GMC was shown to be facile. For the GMC versus AMC support, the higher MnO2 pseudocapacitance is attributed to the higher electronic conductivity, which facilitates electron transport to the MnO2 domains.

The complex structures of the Templated Mesoporous Materials (TMMs) are difficult to capture using experiments. On the other hand, detailed structural information is required in order to study the confinement effects and predict material properties. We therefore present a methodology to prepare realistic molecular models of the TMMs using molecular simulations. Mimetic simulations are used to simulate the synthesis of the TMMs resulting in mesoscale models of the materials. Using this technique, we have developed models for SBA-15 and the Mesostructured Cellular Foams (MCF). The mimetic simulations also allow us to study the phase diagrams of the surfactants involved in the synthesis. We have investigated the ternary phase diagrams (surfactant-oil-water and surfactant-silica-water) of model triblock surfactants and have highlighted the effects of oil on the ordered structures. The simulation results for the effect of oil are in partial agreement with the experiments. Next, we devise a technique to convert the mesoscale TMM models into atomistic ones. The method has been demonstrated by preparing atomistic models for SBA-15. The physical properties of the models (pore size distribution, surface area, TEM and AFM images) are compared to the experimental ones. The porosities and the surface areas of the models are in quantitative agreement with those of the experimental SBA-15, whereas the pore size distribution and TEM results agree qualitatively with the experiments. We also present new methods for characterizing model structures including a fast technique for computing pore size distributions. The results from our new technique show speed increases of several orders of magnitude compared to the existing method. Finally we simulate the adsorption of Argon inside the model SBA-15 using Grand canonical Monte Carlo simulations. The adsorption isotherm from the model is in semi-quantitative agreement with that of an experimental SBA-15. The adsorption behavior of several different pore models are investigated, which provides new light on the roles of surface roughness and micropores in determining adsorption properties. We conclude by saying that the pore models developed in this work may be used in studying phase transitions, adsorption, diffusion and reactions inside nanopores, and in preparing new mesoporous material models such as the CMK carbons.