Engineering Commons^™

Understanding Biomass Upgrading Through Hydrogenolysis Reactions: Kinetics And Mechanism, Jalal Tavana

Electronic Theses and Dissertations

This dissertation involves several hydrogenolysis reactions but is mainly focused on hydrodechlorination (HDC) of chlorobenzene (PhCl) and hydrodeoxygenation (HDO) of 2-furancarboxylic acid (FCA). Hydrodechlorination of PhCl has been the subject of research for some time. Here, we used a Pd/C catalyst to study this reaction though rigorous kinetics and mechanistic analyses in a CSTR reactor. The H₂/D₂ kinetic isotope effect (KIE) experiment revealed that H₂ is not involved in a rate controlling step. The kinetics data are in agreement with similar systems reported before and follow a first-order dependence on chlorobenzene, half order for hydrogen and …

The Effect Of Moox Reducibility On Its Activity For Anisole Hydrodeoxygenation, Chantal Walker

Electronic Thesis and Dissertation Repository

Catalytic hydrodeoxygenation (HDO) is a process for upgrading crude bio-oil as it has a high oxygen content which causes several undesirable properties. Current methods for HDO use sulfided NiMo and CoMo or supported noble metal catalysts which hydrogenate aromatic rings, leading to less valuable products and increasing the hydrogen consumption. Using 10 wt. % MoO3 supported on ZrO2, TiO2, γ-Al2O3, SiO2 and CeO2, we investigated the atmospheric HDO of anisole, a model compound, at 350 °C. All catalysts achieved C – O bond cleavage, preserving the aromatic ring. In situ UV-Vis spectroscopy showed a peak corresponding to intervalence charge transfer …

Understanding The Role Of Atom Trapping In The Evolution Of Hydrocarbon Transformation Catalyst Morphology, Griffin Canning

Chemistry and Chemical Biology ETDs

Converting alkanes to other, more chemically and economically valuable molecules requires catalysts that can survive elevated temperatures and highly reducing environments. These environments can cause many metal-nanoparticle based catalysts to sinter rapidly, causing a loss of activity. They must also tolerate the coke formation, as well, since coke can restrict access to active sites by gas phase molecules, thus lowering catalytic activity. While there are routes to improve both the sinter and coke resistance of catalysts, an alternative strategy is to develop a protocol for regenerating the activity of the catalyst in question when coke formation or sintering becomes problematic. …

Rational Design Of Non-Noble Metal Intermetallic Compounds With Tunable Surface And Catalytic Chemistry Via Combined Computational And Experimental Method, Yuanjun Song

Doctoral Dissertations

This study focuses upon understanding and rationally tuning the surface reactivity towards C, H, and O of non-noble metal intermetallic compounds (IMCs) catalysts in olefin production and hydrocarbons reforming reactions. In these reactions, different degrees of surface reactivity towards C, H, and O are required to achieve high activity and selectivity as well as stability. A combined computational and experimental method was performed to build this understanding how to rationally design catalysts. Investigations based on quantum chemical calculations indicate surface reactivity towards C, H, and O is a function of element size of constituent elements as well as bulk and …

Advanced Materials For Air Pollutants Removal In A Combustion System, Sungyoon Jung

McKelvey School of Engineering Theses & Dissertations

Air pollutants directly or indirectly impact human health and the environment. Large quantities of CO2, volatile organic compounds (VOCs), and particulate matter are emitted from combustion systems, and cause climate change, smog formation, and pose serious health risks. The increasing demand for the remediation of air pollutants at the source has drawn much attention to the use of advanced materials due to their high reactivities and special properties. In order to achieve the successful application of advanced materials for the remediation of problematic emissions, three aspects, (1) synthesis method, (2) characterization of materials’ structural properties, and (3) evaluation of materials’ …

Development And Characterization Of Robust And Cost-Effective Catalysts For Selective Biomass Upgrading To Fuels And Chemicals By Deoxydehydration, Bryan E. Sharkey

Doctoral Dissertations

The use of biomass-derived ligno-cellulose as a possible alternative source of fuels and chemicals to fossil-based hydrocarbons, however, biomass offers many challenges based on processing and its high oxygen content. One promising upgrading route is deoxydehydration, a reaction which combines a deoxygenation by a sacrificial reductant and dehydration in a single step to selectively convert vicinal diols into an olefin. This reaction is highly selective when using homogeneous oxo-rhenium catalysts, which can easily undergo the necessary changes in coordination and oxidation state, however the high cost of rhenium and difficulty of homogeneous catalyst recovery make these catalysts untenable for large …

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 …

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 …

Engineering Dopant Position In Structure-Controlled Ceo2-Zro2 Catalysts, Behnam Safavinia

LSU Master's Theses

CeO₂-ZrO₂ (CZO) nanoparticles (NPs) have application in many catalytic reactions, such as methane reformation, due to their oxygen cycling ability. Ni doping has been shown to improve the catalytic activity and acts as an active site for the decomposition of methane. In this work, Ni:CZO NPs were synthesized via a two-step co-precipitation/molten salt synthesis to compare Ni distribution, oxygen vacancy concentration, and catalytic activity relative to a reference state-of-the-art catalyst. To better understand the effects of Ni position and dispersion, and oxygen vacancy formation in these materials, the Ni concentration, reaction time, and deposition methods were varied. …

Engineered Nanoparticles For Site-Specific Bioorthogonal Catalysis: Imaging And Therapy, Riddha Das

Doctoral Dissertations

Bioorthogonal catalysis offers a strategy for chemical transformations complementary to bioprocesses and has proven to be a powerful tool in biochemistry and medical sciences. Transition metal catalysts (TMCs) have emerged as a powerful tool to execute selective chemical transformations, however, lack of biocompatibility and stability limits their use in biological applications. Incorporation of TMCs into nanoparticle monolayers provides a versatile strategy for the generation of bioorthogonal nanocatalysts known as “nanozymes”. We have fabricated a family of nanozymes using gold nanoparticles (AuNPs) as scaffolds featuring diverse chemical functional groups for controlled localization of nanozymes in biological environments, providing unique strategies for …

Nanostructured Metal Thin Films As Components Of Composite Membranes For Separations And Catalysis, Michael J. Detisch

Theses and Dissertations--Chemical and Materials Engineering

Novel metallic thin film composite membranes are synthesized and evaluated in this work for improved separations and catalysis capabilities. Advances in technology that allow for improved membrane performance in solvent separations are desirable for low molecular weight organic separation applications such as those in pharmaceutical industries. Additionally, the introduction of catalytic materials into membrane systems allow for optimization of complex processes in a single step. By adding a nanostructured metallic thin film to its surface, a polymer membrane may be modified to exhibit these improved properties. Using magnetron sputtering, thin metal films may be deposited on commercially available membranes to …