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Supported Metal Bifunctional And Bimetallic Catalysts With Precisely Controlled Structures And Properties, Anhua Dong

Theses and Dissertations

In heterogenous catalysis, metallic nanomaterials play vital roles in numerous chemical processes. However, monofunctional catalysts are greatly impeded in their applications especially in the systems including tandem and/or sequential reaction steps. Besides, the catalytic performance can also be greatly influenced by the particle size, morphology, and geometry of the surface metal atoms.

The goal of this work is to synthesize bifunctional or bimetallic nanoparticles with high metal dispersion and homogenous alloys by rational synthetic strategies to facilitate the catalyst function. Strong electrostatic adsorption (SEA) is an effective and facile methodology to produce well dispersed and uniform nanoparticles. Metal-acid bifunctional catalysts …

Recent Advances In Catalytic Ethylene Epoxidation: Synthesis, Characterization, And Evaluation, Benjamin Thomas Egelske

Theses and Dissertations

First synthesized in 1859 by French chemist Charles-Adolphe Wurtz, ethylene oxide (EO) is produced from the direct epoxidation of ethylene and molecular oxygen over a low surface area α-Al₂O₃ supported silver (Ag) catalyst [1-6]. With a production capacity over 35 Mt/year, EO is the largest chemical by volume synthesized from a heterogeneously catalyzed process and is used in the production of ethylene glycol, ethoxylates, and ethanolamines [6, 7]. State-of-the-art catalyst formulations contain high loadings of Ag, typically 12-30wt%, required to recover activity in the presence of promoter elements which increase EO selectivity from ~75% for unsupported Ag to 80% for …

Insights Into Rational Catalysts Synthesis, Abolfazl Shakouri

Theses and Dissertations

Atomically distributed metal centers with maximized atom utilization efficiency called single-atom catalysts (SACs) have attracted significant attention in catalysis. SACs with the advantages of both homogeneous and heterogeneous catalysts have been rising as a new frontier in the field of catalysis. New catalytic technologies are ever-growing, considering 90% of all chemical processes employ catalysts, securing modern society’s sustainable future. A classical field in catalysis has been dedicated to catalysis by supported metals. Recently, a vast effort has been devoted to smaller catalyst particles where size is restricted to a single atom on a surface. Single atoms supported or embedded on …

Solvent Effect Modeling In Heterogenous Catalysis, Mehdi Zare

Theses and Dissertations

In recent years, the biorefining industry and biofuels have emerged as a major American energy sector. Biofuels are fuels produced from plant and animal material, also referred to as biomass. This includes wood products, manure, and corn, among other materials. Compared to fossil fuels, biofuels are significantly more environmentally friendly and thus pose less of a threat to environmental health. In 2019, the United States consumed around 14.54 billion gallons of ethanol and around 1.81 billion gallons of biodiesel. By 2030, the United States is expected to consume around 95 Mtoe of biofuels. In order to meet current demand and …

Investigation Of Oxidized Carbon Supported Au Catalysts Synthesized Via Strong Electrostatic Adsorption Of Au(En)2Cl3 For The Hydrochlorination Of Acetylene To Vinyl Chloride Monomer, Sean Reginald Noble

Theses and Dissertations

Over 20 million tons of vinyl chloride monomer (VCM) is produced every year using acetylene hydrochlorination using a supported mercuric chloride catalyst. During this process mercury is reduced and sublimes into the environment harming all living animals and humans, so carbon-supported Au catalysts have been developed in attempts to replace it. Various techniques have been used to make these catalysts including several variations of dry impregnation. In this study we investigate the ability of Strong Electrostatic Adsorption (SEA) of Au(en)₂Cl₃ onto various supports to demonstrate the ability to rationally and consistently synthesize gold catalysts with ultra-small particle …

Solid Materials Discovery For Thin Films, Oxide Catalysts, And Polymer Sealants, Benjamin Ruiz-Yi

Theses and Dissertations

Solid materials are made up of multiple classes, including metals, ceramics, and polymers. While each class can be developed for general purpose applications or highly specialized, discovery of new materials in order to improve upon desired properties is a non-trivial task for any type of material. A wide variety of materials encompass expansive design spaces, consisting of parameters such as chemical compositions, synthesis conditions, and post-processing. Due to this, narrowing down the design space to fit within a given figure-of-merit and economic viability becomes time consuming at best and infeasible at worst. High-throughput experimentation

High-throughput experimentation (HTE) is a methodology …

The Synthesis Of Solid Supported Palladium Nanoparticles: Effective Catalysts For Batch And Continuous Cross Coupling Reactions, Kendra W. Brinkley

Theses and Dissertations

Catalysis is one of the pillars of the chemical industry. While the use of catalyst is typically recognized in the automobile industry, their impact is more widespread as; catalysts are used in the synthesis of 80% of the US commercial chemicals. Despite the improved selectivity provided by catalyst, process inefficiencies still threaten the sustainability of a number of synthesis methods, especially in the pharmaceutical industry. Recyclable solid supported catalysts offer a unique opportunity to address these inefficiencies. Such systems coupled with continuous synthesis techniques, have the potential to significantly reduce the waste to desired product ratio (E-factor) of the production …

Theoretical Investigation Of The Catalytic, Liquid-Phase Hydrodeoxygenation Of Organic Acids And Esters, Sina Behtash

Theses and Dissertations

With worldwide fossil fuel resources dwindling and greenhouse gas emissions rising, it is urgent to find renewable liquid fuel alternatives from e.g. biomass to meet the world’s growing energy demand. Lipid feedstocks and pyrolysis oils from woody biomass can be utilized for the production of second-generation biofuels via a catalytic hydrodeoxygenation (HDO) process. The conversion of fatty acids and esters plays an important role in the activity and selectivity of these processes. Understanding the HDO reaction mechanism of organic acids and esters on metal surfaces is a prerequisite for the rational design of new HDO catalysts specifically designed for upgrading …

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 …

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 …

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 …

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.