Engineering Commons^™

Phenol Deoxygenation Over Hydrotreating Catalysts, Madelyn R B Ball

Honors Theses and Capstones

Phenol deoxygenation has been investigated as a model reaction for the deoxygenation of fatty acid methyl esters in biodiesel. Hydrodeoxygenated biodiesel is a drop-in fuel for petroleum diesel, and is a premium diesel with a high cetane number. As the first step in this research, two molybdenum catalysts were prepared, characterized and tested in a small-scale reactor. These catalysts were found to produce small amounts of benzene and cyclohexanol in the product stream, and confirmed the activity of the catalyst. A commercial cobalt molybdenum catalyst (Harshaw HT-400) was also tested and benzene, cyclohexanol, and cyclohexane were identified as products. Future …

Preparation Of Mesoporous Silica Supported Ruthenium Oxides And The Application And Kinetic Study In The Catalysis Of Water Oxidation, Yang Zhang

Open Access Dissertations

Photo-induced water splitting of water into H2 and O2 has been a major focus in the development of clean and renewable energy. The development of viable and efficient catalysts that facilitates O2 production remains the major challenge in the study of the corresponding half-reaction of water oxidation. There are plenty of metal oxides reported active in the catalysis of water oxidation. However, several important performance bench marks of those materials, such as the non-stoichiometric production of O2, slow reaction rate and/or low quantum efficiency, remain to be improved.

Ruthenium oxide (RuO2) has long been known as one of the most …

High-Pressure Vapor-Phase Catalytic Hydrodeoxygenation Of Lignin-Derived Compounds To Hydrocarbons On Bimetallic Catalysts In The Range Of 0.2-2.4 Mpa., Sara Lynn Yohe

Open Access Dissertations

Biomass, as the only renewable source of carbon, presents a sustainable alternative to liquid fossil fuels for the production of renewable transportation fuels and chemicals. The lignin portion of biomass poses a significant challenge in the upgrading and conversion of lignocellulosic biomass to fuels and chemicals, and in many current biorefineries is not utilized. However, the lignin fraction is a valuable feedstock due to its aromatic structure, lower O:C ratio than cellulose and hemicellulose, and high energy content (up to 40%) and weight fraction (average 25 wt%) of biomass. Several processes (including fast-pyrolysis, fast-hydropyrolysis, and liquid phase processing) are able …

Effect Of Nanoparticle Size, Support, And Potassium Dopant On Ruthenium Activity For Levulinic Acid (La) Hydrogenation To Γ-Valerolactone (Gvl), Shuo Cao

Theses and Dissertations

The purpose of this thesis is to study the effect of nano-particle size, support and potassium dopant on ruthenium activity on the levulinic acid (LA) hydrogenation to ã-valeroactone (GVL).In hydrogenation reaction, H2 as the gas phase reactant reacts with the metal atoms at the surface of particle size, thus a high level of metal dispersion is critical to maximize the amount of atoms on the surface. This reaction has been widely investigated by varied metal supported catalysts and proved that Ru is the most active metal for it. However, most of researchers only focused on the reaction pathway, rather than …

Model Pt- And Pd-Based Electrocatalysts For Low Temperature Fuel Cells Applications, Selasi Ofoe Blavo

USF Tampa Graduate Theses and Dissertations

In the search for alternative energy technologies, low temperature fuel cells continue to feature as technologies with the most promise for mass commercialization. Among the low temperature fuel cells, alkaline and proton exchange membrane fuel cells are the most popular. Alkaline fuel cells have typically been used for water generation as well as auxiliary power for space shuttles. Their bulkiness however makes them undesirable for other applications, especially in automobiles, where there is a great demand for alternative technologies to internal combustion engines. Proton exchange membrane fuel cells on the other hand possess numerous qualities including their compact size, high …

Utility Of 1,2,4-Triazoles As Catalysts For Orr In Fuel Cells, Chinmay Nagesh Dabke

Masters Theses

The Oxygen Reduction Reaction (ORR) taking place at the cathode of a fuel cell is catalyzed by Platinum due to its high activity and good stability in the acidic polymer electrolyte membrane fuel cell (PEMFC) environment. Due to its prohibitive cost and limited reserves, it is not practical to use Pt as the catalyst for mass commercialization. By taking inspiration from nature, we have devised a series of catalysts which will help in replacing Platinum at the cathode in commercial fuel cells. To gauge the activity of various ligands, metal salts and carbon surfaces, adsorbed experiments were carried out and …

Homogeneous Viologens For Use As Catalysts In Direct Carbohydrate Fuel Cells, Dane C. Hansen

Theses and Dissertations

Deriving electrical energy from glucose and other carbohydrates under mild conditions is an important research objective because these biomolecules are abundant, renewable, and can provide 12 to 24 electrons per molecule, yielding substantial electrical power. It was previously observed that disubstituted viologens, salts of N,N'-disubstituted 4,4'-bipyridine, are able to oxidize glucose under alkaline conditions. Building on that initial result, the objective of this work was to understand and quantify the effectiveness and utility of viologens as catalysts for use in direct carbohydrate fuel cells.The extent that viologens oxidize carbohydrates, the conditions under which that oxidation occurs, and the mechanism for …

Synthesis, Characterization, And Testing Of Atomically-Precise Au Clusters Supported On Tio₂ For Co Oxidation, Sarthak Gaur

LSU Doctoral Dissertations

Supported Au catalysts have been studied extensively for CO oxidation. These catalysts are known to catalyze this reaction even at sub-ambient temperatures. While recent literature demonstrates catalytic activity of gold nanoparticles <2 nm, the next stage in fine tuning this catalysis process is to develop gold clusters prepared with atomic precision. Such atomically precise gold catalysts supported on TiO2 hitherto have not been investigated for CO oxidation. The main objective of this work is to synthesize atomically-precise Au38 clusters in a flask-based method using principles of wet chemistry, to characterize these clusters using various advanced spectroscopic techniques, and to test these clusters as potential catalytic materials for CO oxidation. Furthermore, we have tested TiO2-supported Au38 clusters and a commercially purchased Au/TiO2 catalyst for CO oxidation at 30 °C and 60 °C, and used DRIFTS as a probe spectroscopic technique to correlate kinetics with the mechanism occurring on the surface of both catalysts in order to device the mechanistic pathways for CO oxidation. The work reported in this dissertation is the first spectroscopic observation of the phenomena where sulfur may have beneficial effect on the catalytic activity of Au/TiO2 catalysts. Such an interesting observation where sulfur has beneficial effect on catalytic activity of Au/TiO2 catalysts has never been observed in the past. We have also synthesized and tested Fe3O4@Au core-shell nanoparticles supported on TiO2 for CO oxidation. We show for the first time that, core-shell type nanogold catalysts are better suited compared to pure gold nanoparticles for heterogeneous gas phase catalysis of CO oxidation. By conducting comprehensive experiments towards understanding CO oxidation catalysis using X-ray photoelectron spectroscopy, infrared spectroscopy, and temperature programmed reduction, we show that the enhanced catalytic activity is due to a combination of factors ranging from synergistic interaction between Au and Fe, complete removal of organic capping ligands and the presence of metallic gold (Au0) in the active catalyst.

Nickel-Based Catalysts For Gasification Of Glucose In Supercritical Water, Muhammad Badrul Islam Chowdhury

Electronic Thesis and Dissertation Repository

Gasification of waste biomass to form hydrogen, H2, is a promising new source of green energy; while providing the additional benefit of treating challenging and hazardous waste streams that pollute the environment. Gasification of biomass in supercritical water (SCW) offers an attractive alternative to avoid the energy intensive drying process. In this approach, biomass is hydrolyzed by water into smaller molecules in the presence of a suitable catalyst. This study was aimed at developing an alumina supported nickel based non-noble metal catalyst suitable for biomass gasification in SCW. A lack of detailed characterization on fresh and spent catalysts in SCW …

Catalytic Fast Pyrolysis Of Biomass For The Production Of Fuels And Chemicals, Torren Ryan Carlson

Open Access Dissertations

Due to its low cost and large availability lignocellulosic biomass is being studied worldwide as a feedstock for renewable liquid biofuels. Currently there are several routes being studied to convert solid biomass to a liquid fuel, which involve multiple steps at long residence times thus greatly increasing the cost of biomass processing. Catalytic fast pyrolysis (CFP) is a new promising technology to convert directly solid biomass to gasoline-range aromatics that fit into the current infrastructure. CFP involves the rapid heating of biomass (~500˚C sec-1) in an inert atmosphere to intermediate temperatures (400 to 600 ˚C) in the presence of zeolite …

X-Ray Absorption Spectroscopy Applied To Mixed-Metal Iron-Based Fischer-Tropsch Catalysts, Andrew Allen Campos

LSU Doctoral Dissertations

Synthetic fuels derived from methane, coal or biomass are essential in addressing future transportation fuel demands which are expected to exceed petroleum-derived capacities. The Fischer-Tropsch synthesis (FTS) is the most studied technique for the conversion of coal or biomass-derived syngas into transportation fuels. Fe-based catalysts are typically used for the FTS of biomass and/or coal-derived syngas due to: the relatively low cost of iron, water-gas shift activity, and low methane selectivity at industrial FTS conditions. Fe/Cu/SiO2 Fischer-Tropsch catalysts promoted with Cr, Mn, Mo, W, or Zr were studied in-situ, using Fe K-edge TPR XANES (temperature programmed reduction X-ray absorption near-edge …

Microkinetic Model Of Fischer-Tropsch Synthesis On Iron Catalysts, Uchenna Prince Paul

Theses and Dissertations

Fischer-Tropsch synthesis (FTS), developed in the early 1900's, is defined as the catalytic conversion of H2 and CO to hydrocarbons and oxygenates with the production of H2O and CO2. Accurate microkinetic modeling can in principle provide insights into catalyst design and the role of promoters. This work focused on gaining an understanding of the chemistry of the kinetically relevant steps in FTS on Fe catalyst and developing a microkinetic model that describes FTS reaction kinetics. Stable Al2O3-supported/promoted (20% Fe, 1% K, 1% Pt) and unsupported Fe (99% Fe, 1% Al2O3) catalysts were prepared and characterized. Transient experiments including temperature programmed …

Heterogeneous Catalysis And Biodiesel Forming Reactions, Dora Lopez

All Dissertations

Biodiesel, defined as 'a fuel comprised of mono-alkyl esters of long chain fatty acids derived from vegetable oils or animal fats', is finding favor commercially worldwide. The objective of this study is to evaluate the use of solid catalysts for triglyceride transesterification and carboxylic acid esterification to produce biodiesel fuel.
Processes using mainly homogeneous alkali catalysts (such as NaOH, KOH, and methoxides) have been shown to be effective for biodiesel synthesis when dealing with virgin oil feedstocks. Use of acid catalysts (e.g., H2SO4) becomes important when processing low quality feedstocks that contain appreciable amounts of free fatty acids, such as …

Catalytic Partial Oxidation Reforming Of Jp8 And S8, Thomas G. Howell

Theses and Dissertations

Catalytic partial oxidation (CPOX) reforming experiments were performed using a 10 kW Aspen Products Group, Inc. fuel processing prototype utilizing military logistic fuels JP8 and S8. S8 is a sulfur-free Fisher-Tropsch fuel, while JP8 is a multi-fuel blend, which could impact reforming efficiency, product distribution and byproduct production. Sulfur contained within the JP8 will adversely affect the product distribution; therefore, desulfurization beds, capable of removing up to 1000 ppm sulfur, were incorporated into the system. The catalyst used in the prototype is noble metal dispersed on cordierite monolith. The goal of this experiment was to evaluate the efficiency and product …

Generation Of Biomarkers From Anthrax Spores By Catalysis And Analytical Pyrolysis, Phillip R. Smith

Theses and Dissertations

Anthrax spores, in weaponized form, are dangerous biological warfare agents. Handheld technology for the rapid detection of anthrax is greatly needed to improve national security. Methods to detect anthrax spores are diverse, with most taking at least an hour for positive identification. A viable option for rapid detection is analytical pyrolysis (AP), which produces chemicals containing taxonomical information (biomarkers). AP methods are reviewed and critically analyzed to show that reproducible detection of anthrax spores in a rapid manner (< 5 min) with a handheld device is not currently possible. A promising alternative to AP is the use of a catalyst to produce biomarkers from anthrax spores with improved selectivity and reproducibility. Catalytic materials having promise for this include platinum, nickel, and superacids. Experiments evaluating several of these materials are described. A biomarker mass spectral library was created, based on information available in the scientific literature, to facilitate analysis and identification of the biomarkers produced experimentally. The RAMFAC algorithm was used to deconvolute chromatographic peaks to produce clean mass spectra and match them against entries in the biomarker library. While the library is not complete, its use with the RAMFAC algorithm enabled detection of many important biomarkers in experiments involving catalytic breakdown of anthrax spores. Experimental results from preliminary tests of several catalysts are presented and discussed. Addition of catalysts in the form of platinum nanoclusters and superacids to bacterial spores in a commercial pyrolyzer effected an increase in the amount of biomarkers produced at mild conditions over traditional pyrolysis methods. Electroformed nickel mesh, on the other hand, demonstrated low catalytic activity for the production of biomarkers, likely due to poor contact of the spores with the mesh. Biomarkers similar to those published in the literature were observed, including dipicolinic acid, picolinic acid, propionamide, acetamide, diketopiperazines, fatty acids, furfuryl alcohol, and DNA bases. A statistically designed factorial study was used to determine the importance of temperature, spore loading, and nanocluster loading on the production of three important biomarkers. The relative importance of these variables differs for each of the three important biomarkers, suggesting they are produced by different reaction mechanisms.

The Heterogeneous Catalytic Decomposition Of Isopropyl Alcohol Over 0.5% Platinum On 4-8 Mesh Charcoal Catalyst Support, Thomas Michael Kudenchak

Theses

The heterogeneous catalytic decomposition of isopropyl alcohol vapor over 0.5% platinum on (4-8 mesh) charcoal support catalyst was studied at bench-top in a fixed-bed tubular micro-reactor of about 1 cm ID, six inches long containing one or two grams of catalyst. Reactor feed and exit gas analysis was obtained by gas chromatography.

Experimental runs aimed at determining the Arrhenius parameters and the reaction order (assuming the applicability of a simple power law model) were performed with 1 and 2 grams of catalyst at various residence times ranging from 0.24 to 2.3 seconds and temperatures of 150°, 175°, 200°, 225°, and …