Engineering Commons^™

Computationally-Driven Insights Into The Ligand Environments Of Materials For Catalysis And Separations, Stephen Vicchio

All Dissertations

Designing new catalytic and sorption materials is necessary to limit global temperature rise below 1.5 ◦C by 2050, while also meeting global energy demands. Climate change and energy production are not mutually exclusive; global population growth has direct impacts on global energy demands and climate. In both catalysis and adsorption applications, new technologies are needed to address these challenges. Catalysis can provide alternate, low-energy routes for converting low-value gases into higher-value chemical commodities, thus altering our current energy production. Likewise, new sorption materials can capture previously emitted CO₂ from decades of energy production from fossil fuels, thus helping to …

Catalytic Consequences Of Catalyst Pellet Architecture On The Methanol To Oxymethylene Process, Sebastian M K Cook

Electronic Thesis and Dissertation Repository

A critical step for the synthesis of renewable oxy methyl ethers (OME) targeted towards diesel substitution, is the catalytic production of a dimethoxymethane/formaldehyde mixture from methanol and air. The bifunctional catalyst requirements needed for methanol to undergo both the acidic and oxidative steps required for dimethoxymethane formation have been recently established for TiO₂-supported vanadia catalysts. However, translating these requirements to a catalyst capable of industrial operation remains a challenge. This thesis examines the considerations and adjustments needed to translate the molecular active phase to a large-scale catalytic pellet, including active phase distribution and possibility of hot-spot creation during …

Phosphorus-Containing Zeolites For Biofuel Production, Jason Gulbinski

Doctoral Dissertations

Fossil fuel consumption increases 2% a year due to transportation fuels and specialty chemicals for plastics and synthetic fibers such as p-xylene, a monomer of polyethylene terephthalate. p-Xylene demand was over 50 million tons in 2021 and will increase by 5% a year through 2026. Therefore, sustainable p-xylene production is desired. p-Xylene is produced renewably through Diels-Alder cycloaddition of biomassderived 2,5-dimethylfuran (DMF) with ethylene from bio-ethanol and dehydration over an acid catalyst. Industrial aluminosilicate zeolite catalysts achieve a selectivity of 75%, with loss to side products and coking. A new class of catalysts, phosphoric acid-containing aluminum-free zeolites, P-zeosils, like dealuminated …

Ambient Ammonia Synthesis Via Microwave-Catalytic Materials And Plasma Chemistry, Siobhan Brown

Graduate Theses, Dissertations, and Problem Reports

Ammonia is critical to supporting human life on earth because of its use as fertilizer. The Haber-Bosch process to produce ammonia has been practiced for over 100 years. This process operates at high pressure and temperature to overcome the thermodynamic and kinetic limitations of the ammonia synthesis reaction thus researchers have tried to overcome it for decades. At present this process represents 1% of global energy usage and 2.5% of global CO₂ emissions. The proposed chemical looping ammonia synthesis approach seeks to reduce the environmental impact of this critical process and to elucidate microwave-catalytic principles.

This research aims to …

Elucidation Of Active Site And Mechanism Of Metal Catalysts Supported In Nu-1000, Hafeera Shabbir

All Dissertations

Advances in extraction of shale oil and gas has increased the production of geographically stranded natural gas (primarily consisting of methane (C1) and ethane (C2)) that is burned on site. A potential utilization strategy for shale gas is to convert it into fuel range hydrocarbons by catalytic dehydrogenation followed by oligomerization by direct efficient catalysts. This work focuses on understanding metal cation catalysts supported on metal-organic framework (MOF) NU-1000 that will actively and selectively do this transformation under mild reaction conditions, while remaining stable to deactivation (via metal agglomeration or sintering). I built computational models validated by experimental methods to …

Modeling Solvent Extraction Of Lignin From Hardwoods, Su Pan

McKelvey School of Engineering Theses & Dissertations

This study interprets the observed behavior of solvent extraction of lignin from hardwoods by adapting the framework of the FLASHCHAIN theory (Niksa and Kerstein, 1991; Niksa, 2017). A constitution submodel specifies distributions of molecular weight and reactive sites for native lignin. The model simulates delignification as depolymerization of lignin macromolecules into fragments small enough to be soluble. This process competes with intrachain condensation that consumes labile bridges without forming new fragments, and with recombination that forms larger chains and inhibits further depolymerization. After the soluble fragments are transported from the particle into the bulk solvent, all chemistry continues as long …

Intersections Of Environmentalism, Chemistry, And Racism: An Experimental Study Of Halobenzene Hydrogenolysis And Critical Communication Studies Of Equitable Learning Practices Rooted In Black Feminism, Lauren O. Babb

Electronic Theses and Dissertations

Increasing concentrations of fluorinated aromatic compounds in surface water, groundwater, and soil pose threats to the environment. Fundamental studies that elucidate mechanisms of dehalogenation for C-X compounds (where X represents a halide) are required to develop effective remediation strategies. For halogenated benzenes, previously published research has suggested that the strength of the C-X bond is not rate-determining in the overall rate of dehalogenation. Instead, the rate-determining step has been hypothesized to be adsorption of the C-X compound onto the surface of a catalyst. Building on this hypothesis, in this work, we examine the reaction kinetics of fluorobenzene conversion to benzene, …

Engineering Lewis Acidic Materials For Biomass Conversion And Battery Applications., Md Anwar Hossain

Electronic Theses and Dissertations

My long-term goal is to develop catalytic systems to produce renewable energy for a sustainable society. The overall research objective of my dissertation is to advance understanding of Lewis acidic materials for (1) conversion of renewable lignin into phenolics and (2) enhanced cycling stability of lithium metal batteries to safely store renewable electricity from wind and solar, thereby laying the groundwork for our transition to a sustainable society. Petroleum is a conventional feedstock for current transportation fuels (gasoline, diesel, and jet fuels). However, petroleum is a finite resource and produces greenhouse gases (CO₂ and CH₄) upon processing, …

Computational Study Of The Reactions Of Heteroatomic Compounds On Ceo2, Suman Bhasker Ranganath

LSU Doctoral Dissertations

The mechanisms of ambient-temperature reactions of heteroatomic compounds catalyzed by ceria (CeO₂), an archetypical reducible oxide, for enzyme mimetics, environmental protection, and chemical synthesis are investigated in this dissertation using theoretical methods. CeO₂ is modeled with thermodynamically stable low-index surfaces exposed by commonly studied ceria thin films and nano particles. To understand phosphatase-like dephosphorylation activity, stable adsorption states and surface reactions of model phosphates are examined. Binding of the central P-atom to surface lattice oxygen (O_latt) supplemented by phosphoryl O-Ce interaction is the only stable adsorption state for the un-dissociated molecule. Deprotonation of phosphate monoesters, …

Microwave-Assisted Carbon Nanotube Growth From Methane On Surface Catalyst Exsolving Perovskite Oxide, Angela M. Deibel

Graduate Theses, Dissertations, and Problem Reports

The novel method of using a perovskite exsolution catalyst, strontium titanium nickel oxide (STNO), proved capable of simultaneously producing carbon nanotubes (CNTs) and CO_x-free hydrogen during methane decomposition under microwave irradiation. An optimization of common perovskite materials was conducted for microwave-responsiveness with the results reported in this study. Out of the materials screened, strontium titanium nickel oxide (STNO) was the best candidate to achieve an acceptable methane conversion rate as well as a decent responsiveness to microwave. STNO was further optimized through Ni content, reduction dwell time, and reduction temperature to produce the best methane conversion and CNT …

Modified Electrode Surfaces With Hydrogen Evolution Reaction Catalysts Derived From Electropolymerized Complexes With Redox Active Ligands., Amanda Mae Arts

Electronic Theses and Dissertations

The demand for energy is growing exponentially, and to keep up with these demands new technologies for renewable energy have received increased attention. Hydrogen is one of the most promising energy sources for the future and plays a vital role in water electrolysis and fuel cells, as the hydrogen evolution reaction (HER) is the main step in the water splitting process. To increase the reaction rate and improve efficiency for the water electrolysis, catalysts are used to minimize the overpotential.

Most of the current electrocatalysts for HER are heterogeneous in nature and are dominated by platinum and other precious metals …

Simultaneous Activation Of Stable Molecules- Methane And Nitrogen- Using Microwave Reactor With And Without Plasma- To Produce Ethylene And Ammonia, Sarojini Tiwari

Graduate Theses, Dissertations, and Problem Reports

The discovery of stranded natural gas around the world has made shale gas cheaper and widely accessible. This has driven the relevant research towards the direct utilization of Methane (CH4), a major component of natural gas. CH4 is a highly stable molecule, hence its activation and consequent formation of value-added chemicals in a direct and efficient manner is a relevant problem of the 21st century. All the commercial processes convert natural gas to chemicals indirectly, via the formation of syngas followed by several reactions. The conventional systems are energy intensive and one of the major contributors to green-house gas emissions. …

Microwave-Assisted Natural Gas Conversion To Value-Added Chemicals, Xinwei Bai

Graduate Theses, Dissertations, and Problem Reports

Stranded gas is a raw gas mixture of volatile hydrocarbons where the main composition is methane. The producers flare the stranded gas at the site because the cost of collecting and transporting the gas is higher than the value of the gas itself. To reduce the waste of this natural resource, it is worthwhile to utilize the on-site stranded natural gas as feedstock to produce value-added chemicals without emitting greenhouse gas. Direct natural gas conversion process is more desirable because of lower capital investment. Methane and ethane, the two major components of natural gas, are very stable molecules that usually …

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. …

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 …

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 …

A Study Of Protein And Peptide-Directed Nanoparticle Synthesis For Catalytic Materials, Abdollah Mosleh

Graduate Theses and Dissertations

Nanoparticles have received much attentions due to their unique properties that makes them suitable candidates for a broad range of applications. As the size of particles decreases, their surface area-to-volume ratio would increase which is the main cause of much attention. In addition to the size, their morphologies and compositions may also play important roles for defining unique properties. Nanoparticle synthesis include both bottom-up and top-down strategies. To control the process of inorganic nanoparticles synthesis one could follow the bottom-up approach to have atom-level control over their compositions, morphologies, phases, and sizes which is the subject of this work. Due …

Development Of A Ws2 Catalyst For Hydrogen Evolution And Improvement Via Platinum Nanoparticle Decoration, Alexander O'Brien

Chemical Engineering Undergraduate Honors Theses

In response to a growing global need to improve utilization of green energy, the concept of renewable energy storage via electrolytic hydrogen production has gained popularity in recent years. However, the prohibitive expense of the bulk platinum catalysts currently used for the hydrogen evolution reaction prevents such a concept from being widely adoptable. This research focuses on a possible alternative catalyst, nanolayer WS₂, which is capable of promoting the hydrogen evolution reaction while maintaining economic viability. Bulk WS₂ was prepared in semiconducting, nanolayer form through liquid phase exfoliation. Prepared catalyst inks consisting of this material demonstrated successful …

Elucidation Of The Catalytic Partial Oxidation Of Methane Utilizing The One-Of-A-Kind Catalytic Shock Tube Technique, Robyn E. Smith

Dissertations and Theses

The mechanism for the catalytic partial oxidation of methane has been debated in scientific literature for over 20 years. This is a seemingly simple reaction producing CO, CO₂, H₂ and H₂O through either partial oxidation followed by complete oxidation or complete oxidation followed by reforming steps. What is happening when the reaction is allowed to occur in an environment absent of transport limitations, absent of temperature gradients and temperature changes, absent of boundary layers must be understood and, until now, has yet to be achieved in one experimental technique.

A novel method using a one …

Computational Modeling Of The Structure And Catalytic Behavior Of Graphene-Supported Pt And Ptru Nanoparticles, Raymond Gasper

Doctoral Dissertations

Computer modeling has the potential to revolutionize the search for new catalysts for specific applications primarily via high-throughput methodologies that allow researchers to scan through thousands or millions of potential catalysts in search of an optimal candidate. To date, the bulk of the literature on computational studies of heterogeneous catalysis has focused on idealized systems with near-perfect crystalline surfaces that are representative of macroscopic catalysts. Advancing the frontier to nanoscale catalysis, in particular, heterogeneous catalysis on nanoclusters, requires consideration of low-symmetry nanoparticles with realistic structures including the attendant complexity arising from under-coordination of catalyst atoms and dynamic fluxionality of clusters. …

First-Principles Study On The Catalytic Role Of Cerium Dioxide In The Conversion Of Organic Compounds, Chuanlin Zhao

LSU Doctoral Dissertations

Ceria is an earth-abundant material that has been widely used in heterogeneous catalysis, environmental catalysis, and energy applications thanks for its ability to readily convert between different oxidation states. The objective of this study is to theoretically elucidate the reaction mechanisms for the conversion of model organic compounds on ceria, in order to gain insights for the design of cost-effective and selective ceria-based catalysts. Acetaldehyde, acetic acid, and para-nitrophenyl phosphate monoester were selected as the model compounds to probe ceria surfaces. Density functional theory calculations can provide accurate predictions of adsorption and reaction energetics, which can be used to …

Spectro-Electrochemical Platforms For Dynamic Analyses Of Catalytic Cascade Systems, Nalin I. Andersen

Nanoscience and Microsystems ETDs

The development of spectro-electrochemical platforms that facilitate the dynamic analyses of complex catalytic cascade systems was explored in this research. These systems facilitated multiple modalities of catalysts and were used as platforms for monitoring catalytic transformations quasi-in situ. The analytical platforms allowed for the characterization of intermediates and products using surface-enhanced Raman spectroscopy (SERS). The design and fabrication of these devices proved to be reproducible, made of materials that can be manipulated for multiple applications, and incorporate fluid mechanics, electrochemistry, and multimodal catalysis. Microfluidic technology offers capabilities for understanding catalytic cascade systems by providing precise dynamic control of …

Hydrothermal Decarboxylation Of Fatty Acids And Their Derivatives For Liquid Transportation Fuels, Md Zakir Hossain

Electronic Thesis and Dissertation Repository

Due to the depletion of fossil fuel reserves, renewable resources are required to produce tomorrow’s fuel range hydrocarbons. This thesis focuses on the hydrothermal decarboxylation of fatty acids and their derivatives derived from renewable sources. These are required for liquid transportation fuels which have similar properties to conventional fuels. Detailed catalytic studies were performed for the decarboxylation of oleic acid as a model compound and corn distiller’s oil (CDO) as a real feedstock. Commercial activated carbon and laboratory prepared Ni-Al₂O₃, MgO-Al₂O₃, Mo-Al₂O₃ catalysts were also examined as catalysts. Fatty …

Creating Renewable Tunable Polymers From Hydroxymethylfurfural, Meredith C. Allen

Electronic Theses and Dissertations

The research here deals with the conversion of 5-hydroxymethylfurfural (HMF) into a tunable polymer. HMF is a known derivative that can be acquired from biomass via hydrolysis of cellulose followed by isomerization and finally selective dehydration. The process considered here is being developed to create tunable polymers from HMF and involves several different steps, three of which are covered here. The first step, an etherification, is the reaction of HMF with an alcohol. This step is significant because in this step the R-group from the alcohol is added to HMF and the branching portion formed is carried over to the …

Nanoporous Solid Acid Materials For Biomass Conversion Into Value-Added Chemicals: Synthesis, Catalysis, And Chemistry, Hong Je Cho

Doctoral Dissertations

Growing environmental concerns associated with diminishing reserves of fossil fuels has led to accelerated research efforts towards the discovery of new catalytic processes for converting renewable lignocellulosic biomass into value-added chemicals. For this conversion, nanoporous solid acid materials have been widely used because of their excellent hydrothermal stability and molecular sieving capability. In the thesis, hierarchical Lewis acid zeolites with ordered mesoporosity and MFI topology (three dimensionally ordered mesoporous imprinted (3DOm-i) Sn-MFI) were successfully synthesized within the confined space of three dimensionally ordered mesoporous (3DOm) carbon by a seeded growth method. The obtained 3DOm-i Sn-MFI showed at least 3 times …

A Study Of Iron-Nitrogen-Carbon Fuel Cell Catalysts: Chemistry – Nanostructure – Performance, Michael J. Workman

Nanoscience and Microsystems ETDs

Fuel cells have the potential to be a pollution-free, low-cost, and energy efficient alternative to the internal combustion engine for transportation and small-scale stationary power applications. The current state of fuel cell technology has already achieved two of these three lofty goals. The remaining barrier to wide-scale deployment is the high cost, which is primarily caused by dependence on large amounts of platinum to catalyze the energy conversion reactions. To overcome this barrier and facilitate the integration of fuel cells into mainstream applications, research into a new class of catalyst materials that do not require platinum is needed.

There has …