Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"Mesoporosity"”.
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Materials with engineered mesoporosity for programmed mass transport
Transport in nanostructured materials is of great interest for scientists in various fields, including molecular sequestration, catalysis, artificial photosynthesis and energy storage. This thesis will present work on the transport of molecular and ionic species in mesoporous materials (materials …
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Impact of carbon micro/mesoporosity on the adsorption behavior of small molecules
Adsorption studies on carbon play a key role in fields such as environmental remediation, purification, and catalysis. Because of the inherently high surface area, low cost, and inertness of activated carbons, these materials have been the preferable substrate for remediation studies. The …
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Characterization of a Novel Biodegradable Material to Reduce Emission of Ammonia
… showed that RCC exhibited both macroporosity and mesoporosity whilst SECC showed only mesoporosity. It is interesting to note that upon steam exploding RCC, the macropores within RCC collapsed to form more mesopores in SECC. The high uptake of SECC was determined to be its small pore width …
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Porosity control of alkali-activated aluminosilicates via functional alkoxysilane additives
… MIP results was tested and applied. Geopolymer mesoporosity could be minimized through the use of alkoxysilanes with acrylic acid or similar functional groups, which Fourier transform infrared spectroscopy identified as transforming to sodium acrylates in the high pH of the geopolymer system. …
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Ruthenium-Chromium Oxide Aerogels Oxygen Evolution Electrocatalysts: Structure, Activity and Stability
… oxide aerogels provides high surface area and mesoporosity and enhanced OER activity, and the structure and properties can be modified by thermal treatment temperature.
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Glycerol Oxidation with Zeolite and Hierarchical Zeolite as Catalysts and Electrocatalysts
… the efficient formation of an intraparticle mesoporosity with a narrow pore size distribution depends on the duration of the hydrothermal treatment. For ZSM-5 zeolites only disordered interparticle mesoporosity with a heterogeneous pore size distribution was obtained in the two-step …
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A tour-de-force in polymer crosslinked aerogels
… combine electrical conductivity with a high open mesoporosity. Nevertheless, macropores facilitate mass-transfer and they could be beneficial for applications in separations or as fuel cell and battery electrodes. Here, we report a method where an open macroporosity is introduced by pyrolysing RF …
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Formation of Meso-Structured Multi-Scale Porous Titanium Dioxide by Combined Soft-Templating, Freeze-Casting and Hard-Templating Using Cellulose Nanocrystals
… 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 …
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Plastic Waste-Derived CO2 Sorbents and Methods for Enhanced Selectivity and Stability
… through a liquid-salt templating mechanism. More mesoporosity allowed better accommodation of PEI into the carbon pore network. The PEI-carbon sorbent, although having better uptake and selectivity performance, showed poor stability especially in the presence of oxygen. Oxidative degradation …
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Rational design and synthesis of zeolite acid catalysts for applications in biomass conversion
… reveals high external surface area and mesoporosity and strong external acid sites. MFI nanosheets have higher stability and selectivity to larger olefins and aromatics in the conversion of propanal to hydrocarbons due to shorter diffusion path lengths compared to bulk MFI zeolite. MWW …
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Synthesis and Applications of Monolithic Metal-Organic Frameworks
… via the synthetic inclusion of non-crystalline mesoporosity, was also developed. The generality of this synthetic procedure towards Zr-MOFs in general was further explored including functionalised UiO-66 analogues as well as non- isostructural Zr-MOFs. The capacity of monolithMOFs to host …
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Exploring the Synthesis of Monolithic Metal-Organic Frameworks and their Composites for Advanced Water Management Solutions
… by artificially incorporating non-crystalline mesoporosity. The remarkable potential of monolithic MOFs to serve as hosts for nanoparticles was further evaluated through meticulous studies examining how the surface functionality of nanoparticles affects doping levels in both monoZIF-8 and …
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Impact of carbon support chemistry, morphology, and structure on platinum catalyst durability for PEMFC applications
… were more stable than samples with high mesoporosity (5-20μm), but that porosity increases due to the aging process. The total graphite content was also found to be less important that the surface graphite content. It was determined that the speciation of platinum in the samples had an …
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Lignin valorization
… synthesized carbons showed micro-, macro- and mesoporosity and were tested for their electrocatalytic activity towards the oxygen reduction reaction. Mesoporous carbon derived from nitro lignin displayed the highest electrocatalytic activity. Lignins isolated from coconut, beech wood and bamboo …
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Intrinsic and Extrinsic Catalysis in Zirconium-based Metal-Organic Frameworks
… was largely attributed to the introduction of mesoporosity and nanocrystalline particle sizes, which significantly increase the number of reactive sites easily accessible for catalysis. In Chapter 4 the authors examine MOFs as a host for molecular catalysts for use in photoelectrochemical water …
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Nanostructured carbohydrate-derived carbonaceous materials
… (i.e. Type IV isotherm, SBET = 116 m2g-1, 60 % mesoporosity) generating pore size of ca. 4 nm. It is proposed that in both cases as HTC proceeds to generate a polyfuran-like network, the organised block copolymer micellular phase is essentially “templated”, either via hydrogen bonding between …
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Design of silica-based sustainable biomaterial adsorbents from agricultural waste for the microextraction and adsorptive removal of insecticides and antibiotics from wastewater samples
… confirmed high silica content and mesoporosity (BET surface area and pore volume: 115.855 m²/g and 0.358 cm3/g, respectively). Adsorption experiments revealed the dominance of the Langmuir isotherm (R2 > 0.99), indicating monolayer adsorption on a relatively homogeneous surface, …
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Influence of soil bulk density and matric potential on relative gas diffusivity and urea/nitrate-derived N₂O and N₂ losses
… total soil volume) decreased by 23% while soil mesoporosity and microporosity increased by 6 and 2%, respectively. In Chapter 6, data from the previous experiments (Chapters 4 and 5) was compiled to assess the overall impact of increasing soil ρb on urea‐derived cumulative N₂O‐N and N₂‐N fluxes …
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Biocatalysis on nanostructured surfaces : investigation and application of redox proteins using spectro-electrochemical methods
… tin-rich indium oxide film with a well-defined mesoporosity is reported. The transparency and good conductivity, in combination with the large surface area of these materials, allow the incorporation of a high amount of electroactive biomolecules (between 250 and 2500 pmol cm-2) and their …
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Studies of the formation of homogeneous mixed silicon-titanium/zirconium oxides by the sol-gel route
… increased the micropore volume and decreased the mesoporosity of the resulting samples. Generally, decreasing the amount of acid used for the hydrolysis for silica-zirconia and silica-titania gels (prepared by both methods), results in a decrease in the overall surface area and pore volume of the …
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