Catalysis and Reaction Engineering Commons^™

Xanthan Gum Isolation Alternative Via Ultrafiltration, Anna Beth Malone, Jeffrey Greer, Lareesa Thomas, Lucy Moore

Chancellor’s Honors Program Projects

No abstract provided.

Electrode Development Of Water Electrolyzer Cells For Low-Cost And High-Efficiency Hydrogen Production, Shule Yu

Doctoral Dissertations

A worldwide increase in energy demand and a latent crisis in the fossil fuel supply have spurred broad research in the renewable energy. Currently, most renewable energy resources (e.g., hydro, wind, solar, tide) face supply challenges as they are known to be intermittent, unstable, and locally shackled, which calls for urgent development in energy storage and conversion. Hydrogen is regarded as an ideal energy carrier with its advantages (e.g., high energy density, environmentally friendliness, and low weight). In practice, the proton exchange membrane electrolyzer cell (PEMEC) is considered to be one of the optimal hydrogen production and energy storage devices …

Study Level Recovery Processes Of Thorium And Several Rare Earth Elements From Monazite Ore, Makayla Hyde, Jaclyn Choate

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

Monazite ore is composed of several minerals including several rare earth element (REE) and thorium phosphates. Many past research projects have looked at the extraction of REE from monazite ore but have discarded the thorium phosphate compound as waste. Since thorium could be a possible fuel for state-of-the-art future nuclear reactors, this research focuses on a way to recover thorium from the monazite ore. The overall purpose of this research is to develop a conceptual recovery process that recovers thorium dioxide from monazite ore. In some parts of the world where uranium sources are limited; then, thorium could be used …

Development Of Density-Functional Tight-Binding Methods For Chemical Energy Science, Quan Vuong

Doctoral Dissertations

Density-functional tight-binding (DFTB) method is an approximation to the popular first-principles density functional theory (DFT) method. Recently, DFTB has gained considerable visibility due to its inexpensive computational requirements that confer it the capability of sustaining long-timescale reactive molecular dynamics (MD) simulations while providing an explicit description of electronic structure at all time steps. This capability allows the description of bond formation and breaking processes, as well as charge polarization and charge transfer phenomena, with accuracy and transferability beyond comparable classical reactive force fields. It has thus been employed successfully in the simulation of many complex chemical processes. However, its applications …

The Controlled Synthesis Of Hydrogen Electrocatalysts For Alkaline Exchange Membrane Fuel Cell And Electrolysis Applications Via Chemical Vapor Deposition, Stefan Thurston Dubard Williams

Doctoral Dissertations

The development of catalysts for the electrochemical processes of hydrogen systems (e.g., fuel cells and electrolyzer systems) continues to be an attractive area of research for renewable energy technologies. One significant challenge has been developing hydrogen catalysts suitable for alkaline environments, mainly due to the sluggish kinetics of hydrogen reactions. In alkaline environments, the kinetics are decreased by two orders of magnitude when compared to acidic environments. Chemical vapor deposition (CVD) is a conventional method used to synthesize these types of catalysts. This effort discusses extending work being done using a modified CVD process known as “Poor Man’s” CVD (PMCVD) …

Thorium Dioxide Extraction From Monazite Ore, Katherine Glass

Chancellor’s Honors Program Projects

No abstract provided.

Manufacturing Of Carbon-Based Hybrid Nanocomposites With Engineered Functionalities Via Laser Ablation Synthesis In Solution (Lasis) Techniques, Erick Leonardo Ribeiro

Doctoral Dissertations

Carbon-based composite materials have long been fabricated and extensively used in our daily lives. In the past decades, with rapid development of nanotechnology, these class of material have gained even more attention owing to their outstanding properties which directly results in their prospects to revolutionize technological development in many fields, ranging from medicine to electronics. Nevertheless, for certain applications, including electrochemical energy storage/conversion devices, the chemically inert nature of these materials creates obstacles and thus requires their coupling with other active species. This thesis explores the use of Laser Ablation Synthesis in Solution (LASiS) in tailoring promising strategies and pathways …

Electrochemical Hydrogen Separation Via The Solid Acid Electrolyte Cesium Dihydrogen Phosphate, David Leon Wilson

Doctoral Dissertations

Abundant, inexpensive, high purity molecular hydrogen as a medium for energy distribution is potentially enabling for adoption of alternative electricity generation schemes. Steam reforming of natural gas remains the dominant method of producing large amounts of hydrogen. However, this process also creates by-products, most notably, carbon monoxide and carbon dioxide. Separation to ultra-high purity hydrogen from these syngas reformate streams by traditional methods, such as pressure swing absorption, has its disadvantages including long cycle times, contamination and a large equipment footprint. Alternative methods of hydrogen separation, such as electrochemical pumping, are a viable alternative to this separation dilemma due to …

An Exploration Of Basic Processes For Aqueous Electrochemical Production Of Hydrogen From Biomass Derived Molecules, Brian Fane

Doctoral Dissertations

Polymer electrolyte membrane fuel cells(PEMFCs) are energy conversion devices with significant potential. The factors preventing them from becoming widespread concern production and distribution of hydrogen. Developing an efficient hydrogen infrastructure with an approachable rollout plan is an essential step towards the future of fuel cells. Water electrolysis is limited by the thermodynamics of the process, which leads to high electrical consumption and significant materials challenges. Alternative methods for cleanly generating hydrogen while using a lower cell voltage are required. PEM based electrolyzers can operate with a "depolarized anode", whereby they become significantly less power hungry.

This thesis explores two techniques …

Multiscale Modeling Approach To Understand Active Sites In Non-Conventional Catalyst Layers For Fuel Cell Applications, Diana Constanza Orozco Gallo

Doctoral Dissertations

Fuel cells development required stable, active and more abundant catalytic materials. Oxygen reduction reaction (ORR) is the key process to enhance better activity and reduce the fabrication costs. Pt-based has proven to be the best catalyst for ORR and greater efforts has been made in terms of reducing the Pt content in the electrodes, reduce electrode thickness and enhance better catalytic activities. To overcome many of the challenges present, the catalyst layer studies are the great importance in the fuel cell community. Understanding catalyst layer with new catalytic materials, and configurations requires the development of methodological approach to relate structure, …

Simulating Microbial Electrolysis For Renewable Hydrogen Production Integrated With Separation In Biorefinery, Christian James Wilson

Masters Theses

Biomass conversion to hydrocarbon fuels requires significant amounts of hydrogen. Fossil resources typically supply hydrogen via steam reforming. A new technology called microbial electrolysis cells (MECs) has emerged which can generate hydrogen from organic sources and biomass. The thermochemical route to fuels via pyrolysis generates bio-oil aqueous phase (BOAP) which can be used to make hydrogen. A process engineering and economic analysis of this technology was conducted for application in biorefineries of the future. Steam methane reforming, bio-oil separation and microbial electrolysis unit operations were simulated in Aspen Plus to derive the mass and energy balance for conversion of biomass. …

Catalytic Hydrodeoxygenation And Dehydration Of Bioderived Oxygenates To Renewable Hydrocarbon Building Block Molecules: Enabling Renewable Carbon Fiber, Andrew Walter Lepore

Doctoral Dissertations

It is our goal to develop inexpensive catalytic pathways that can effectively remove oxygen from bio-derived carboxylic acids and alcohols under mild reaction conditions to produce propene which can be converted to renewable carbon fibers. Carboxylic acid hydrodeoxygenation and alcohol dehydration are necessary for successfully producing propene from bio-mass derived precursors and are also broadly relevant to bio-oil upgrading. This body of research adds to the understanding of both known and novel catalyst materials and develops and optimizes pathways for valorizing oxygenates. Dehydration and hydrodeoxygenation catalysts were examined under both batch and continuous flow operation. Product selectivity and reactant conversion …

Innovative Electrode Nanocomposites For Energy Storage And Conversion Systems, Yiran Wang

Doctoral Dissertations

Nanocomposites emerged as suitable alternatives for electrode materials, are defined as “two or more materials with different properties remain separate and distinct on a macroscopic level within one unity and with any dimension in any phase less than 100 nm”. Recently, polymer/carbon based nanocomposites have attracted significant research interests for energy applications due to their multi-functionalities, improved structure stability and ease of production. This dissertation work focusing on the development of innovative electrode nanocomposites for proton exchange membrane fuel cell, supercapacitor and electrochromic applications.

Chapter 1 is an introduction. Chapter 2 & 3 focus on the synthesis of Pd-based nanocatalysts …

Impedance-Resolved Performance And Durability In Redox Flow Batteries, Alan Michael Pezeshki

Doctoral Dissertations

The realization of redox flow batteries (RFBs) as a grid-scale energy solution depends on improving the performance and lifetime of the technology to decrease the high capital costs. The electrodes are a key component in the RFB; performance enhancement is often achieved through chemical or thermal treatments of commercially available porous carbon materials.

This dissertation uses impedance spectroscopy-based methods to gain insight into performance and durability in RFBs, enabling intelligent cell design. Initial work focused on understanding the impact of improved electrode and membrane properties on system performance. An accelerated stress test was then developed that can be used to …

Effects Of Ultrasonic Transducers On Heat Transfer In Packed Particle Beds, David Patrick Moseley

Masters Theses

The objective of this study was to determine the effects of ultrasonic transducers on heat transfer in a packed particle bed heat exchanger. Although substantial research has been devoted to ultrasound, and the associated improvements in heat transfer, data regarding the effects on packed particle beds is non-existent. This is of particular interest given the potential to improve heat transfer in a wide variety of packed particle bed systems. A 42.9% increase in the heat transfer rate was demonstrated as the result of improved fluid convection throughout the packed particle bed. Secondary effects, including acoustic cavitation, acoustic streaming and local …

Lignin Maximization: Analyzing The Impact Of Different Feedstocks And Feedstock Ratios Using Organosolv Fractionation, Marc Banholzer

Masters Theses

Over-exploitation of fossil fuels coupled with increasing pressure to reduce carbon emissions are prompting a transition from conventional petrochemical feedstocks to sustainable and renewable sourced carbon. The use of lignocellulosic biomass as a feedstock for integrated biorefining is of current high interest, as separation into its component parts affords process streams of cellulose, hemicellulose and lignin, each of which can serve as a starting point for the production of biobased chemicals and fuels. Given the large number of potential sources of lignocellulosic feedstocks, the biorefinery will need to adapt to the supplies available over a normal growing season. Of particular …

Tandem Laser Ablation Synthesis In Solution-Galvanic Replacement Reaction (Lasis-Grr): A Facile Route For The Synthesis Of Complex Intermetallic Nanomaterials With Engineered Functionalities, Sheng Hu

Doctoral Dissertations

Tailoring the heteronanostructures of nanoscale materials to tune their structure-property relations for desirable interfacial energetics is imperative for their catalytic, optoelectronic and electrochemical applications. Current PhD thesis develops a facile, yet “green” synthesis route that uses laser ablation synthesis in solution in tandem with galvanic replacement reaction (tandem LASiS-GRR) as a one-pot, one-step technique for manufacturing diverse and complex heteronanostructures of metal oxides, hydroxides, nanocomposites (NCs), and nanoalloys (NAs). The scientific concept here is that the non-equilibrium thermodynamics and kinetics of high-energy LASiS-GRR can be tuned by laser parameters and solvent chemistry to form complex NCs/NAs of tailored sizes/shapes, metastable …

Synthesis Of Ptcuco Ternary Alloy Using Laser Ablation Synthesis In Solution-Galvanic Replacement Reaction (Lasis-Grr), Kangmin Cheng

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

Laser ablation synthesis in solution in tandem with galvanic replacement reaction (LASiS-GRR) is a newly-developed, facile and environmental friendly synthesis technique for manufacturing a variety of complex nanostructures including hydroxides, metal/metal oxides nanocomposites (NCs), metal-metal nanoalloys (NAs), core-shell nanostructures, etc. This synthetic technique incorporates both “top-down” pulsed laser ablation synthesis in solution approach (LASiS) and the “bottom-up” chemical reduction method (CRM). The setup houses a Q-switched Nd:YAG pulsed laser (1064 nm) with the laser beam focused at a metal target in liquid medium inside a sealed stainless steel reactor cell. The cell is mounted with a gas inlet/outlet, viewing windows, …

Computational Simulation Of Mass Transport And Energy Transfer In The Microbial Fuel Cell System, Shiqi Ou

Doctoral Dissertations

This doctoral dissertation introduces the research in the computational modeling and simulation for the microbial fuel cell (MFC) system which is a bio-electrochemical system that drives a current by using bacteria and mimicking bacterial interactions found in nature. The numerical methods, research approaches and simulation comparison with the experiments in the microbial fuel cells are described; the analysis and evaluation for the model methods and results that I have achieved are presented in this dissertation.

The development of the renewable energy has been a hot topic, and scientists have been focusing on the microbial fuel cell, which is an environmentally-friendly …

Oxygen Reduction Reaction By Copper Complex Based Electrocatalysts, Congling Zhang

Doctoral Dissertations

My research focuses on catalysis of oxygen reduction reaction (ORR) by a series of Cu(II) [copper with positive two valence] -1,2,4-triazole complex-based electrocatalysts at the cathode of PEMFC (polymer electrolyte membrane fuel cell), an efficient and environmental friendly energy conversion system compared to internal combustion engines in use today. The sluggish kinetics of ORR considerably limited the performance of PEMFCs. Understanding of ORR mechanism is important for developing affordable, active and durable ORR catalysts for such devices.

The first part of my work focused on improving the ORR performance of Cu(II)-1,2,4-triazole complex-based catalysts in an acidic environment by exploring synthesis …

Development And Demonstration Of Critical Components Of Aluminum Based Energy Storage Devices Using The Chloroaluminate Ionic Liquids, Mengqi Zhang

Doctoral Dissertations

This dissertation considers the development of porous carbon materials as the substrates for Al deposition/dissolution in an Al based ionic liquid flow battery (ILFB) and demonstration of an Al based hybrid supercapacitor. The Aluminum chloride/ 1-ethyl-3-methylimidazolium chloride chloroaluminate ionic liquid is utilized as the electrolyte for these Al based energy storage devices. The ILFB has less capital cost than the all-vanadium redox flow battery because of the inexpensive AlCl₃. The feasibility to equip a tank of solid aluminum chloride in an ILFB system aiming to improve energy density is investigated. A critical range of temperature data (50-130 celsius …

Membrane And Performance Study In Polymer Electrolyte Membrane Fuel Cells And Hydrogen Bromine Redox Flow Batteries, Yujia Bai

Doctoral Dissertations

This dissertation represents the consideration of the problems of polymer electrolyte membrane fuel cells (PEMFC) and hydrogen-bromine redox flow batteries (RFB). Due to the importance of water management in PEMFCs, all the experiments were strictly controlled at different water hydration conditions. Water uptake and densities were measured for Nafion^® and a series of 3M ionomer membranes. The thermodynamics of water and polymer was analyzed based on water uptake experiment and calorimetry. Furthermore, partial molar volumes (PMV) of water/membrane system was defined for the first time and used to analyze the interaction between water and polymers. Three states of water …

A Study About Aqueous Reversible Air Electrode- Catalyst, Electrolyte And Structure, Ming Qi

Doctoral Dissertations

Developing a better high energy density rechargeable battery has becoming critically important for several industries. For building such kind of battery, reversible air electrode has been widely accepted as one of the key components. One of the major challenges for reversible air electrode is finding a good bifunctional catalyst to greatly reduce the recharge overpotential and increase the system efficiency. To achieve this goal, a new air battery chemistry based on cobalt salen modified Au catalyst is proposed in this dissertation as a very promising solution. The unique catalytic activity of this catalyst is found to be a two electron …

Structure And Energetics Of Nanoparticles And Ionomer Films In Fuel Cell Catalyst Layers, Qianping He

Doctoral Dissertations

Improving the durability and utilization efficiency of the platinum-on-carbon (Pt/C) catalyst is of vital importance to the commercialization of the polymer electrolyte membrane fuel cell (PEMFC). This body of work provides molecular level insights to aid the fulfillment of this goal. Chapter 1 describes the use of molecular dynamics (MD) simulation in an effort to understand the Pt/C degradation issue from the nano-adhesion point of view. The roles of catalyst nanoparticle size, shape, Pt/C surface oxidation and the extent of ionomer film hydration are investigated to study their effects on nano-particle adhesion. It is found that the adhesion force strengthens …

The Impact Of Biodiesel-Based Na On The Durability Of Cu-Zeolite Scr Catalysts And Other Diesel Aftertreatment Devices, Daniel William Brookshear

Doctoral Dissertations

Biodiesel fuel has increased in popularity in recent years as an alternative fuel choice, but there are concerns related to the impact it will have on diesel engines and aftertreatment systems relative to conventional diesel fuel. One major concern is the presence of sodium (Na) in finished biodiesel fuel due to the use of Na-hydroxyl as a liquid-phase catalyst during biodiesel synthesis. The current study focuses on determining the impact of biodiesel-based Na on the performance and materials characterization of diesel aftertreatment devices including lean NOx traps (LNT), diesel oxidation catalysts (DOC), diesel particulate filters (DPF), and Cu-zeolite selective catalytic …

Lignin Yield Maximization Of Lignocellulosic Biomass By Taguchi Robust Product Design Using Organosolv Fractionation, Anton Friedrich Astner

Masters Theses

Lignin, a byproduct of the organosolv pretreatment process using lignocellulosic biomass from switchgrass (Panicum virgatum) and tulip poplar (Liriodendron tulipifera) is currently being explored for its potential use in the production of value-added chemicals and biobased polymers. Pretreatment is one of the most expensive processing steps in cellulosic biomass conversion. Optimization of the process is one of the major goals of the biomass-toethanol conversion process. Taguchi Robust Product Design (TRPD) provides an effective engineering experimental design method for optimizing a system and designing products that are robust to process variations. Given the results of several preliminary …

The Synthesis And Characterization Of Novel Group 13 Nanostructured Building Block Heterogeneous Silicate Catalysts, Joshua G. Abbott

Doctoral Dissertations

A building block approach and sequential addition methodology were utilized to prepare heterogeneous silicate catalysts containing atomically dispersed group 13 metal (B, Al, Ga) centers. The octa(trimethyltin) silsequioxane, Si8[sub]O12[sub](OSnMe3[sub])8[sub], was used as the building block for the synthesis of these materials. Reaction of the building block with a variety of group 13 metal chlorides led to the formation of cross-linked matrices. All prepared materials were characterized by gravimetric analysis, gas absorption, IR, and NMR. In addition, aluminum and boron samples where characterized by 27[sup]Al and 11[sup]B solid state NMR, and gallium samples were studied using x-ray absorption techniques.

Studies found …

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 …

Gas To Liquids (Gtl), Andrew David Hix, Mark Moore, Rachel Kendall, Rachel Svoboda, William Maningas

Chancellor’s Honors Program Projects

No abstract provided.

Roles Of Non-Thermal Plasma In Gas-Phase Glycerol Dehydration Catalyzed By Supported Silicotungstic Acid, Lu Liu

Doctoral Dissertations

Acrolein is an indispensable chemical intermediate with a rising demand in recent years. The concern of the increase of propylene prices due to the shrinking supply of nonrenewable crude oil makes the acid-catalyzed gas-phase glycerol dehydration to acrolein a prime candidate for research. Our analysis showed that the sustainable acrolein production from glycerol was both technically and economically viable. Alumina2700^® (Al) and Silica1252^® (Si) loaded with silicotungstic acid (HSiW) possessed distinct features while provided equally good acrolein yield (73.86mol% and 74.05mol%, respectively) optimally.

Due to the unique non-equilibrium characteristics, non-thermal plasma (NTP) could promote a variety of chemical …