Catalysis and Reaction Engineering Commons^™

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 …

Optimizing Virus Prefiltration For Biopharmaceutical Manufacturing, Solomon Isu

Graduate Theses and Dissertations

Virus filters are single-use devices that use a size-based separation process. In virus filters, contaminating virus particles are retained while the therapeutic molecules pass through the membrane pores. Virus filters are an essential component of the overall virus clearance strategy. Sections 1 and 2 of this dissertation provide an introduction and extensive review of monoclonal antibody (mAb) process development, where virus filtration is pivotal. In section 3, prefiltration studies were performed with an industrially relevant IgG1 type mAb using adsorptive and size-exclusion-based prefilters with different mechanisms of action. This mAb has an isoelectric point range of 7.1 to 8.0 and …

Catalytic Ring Opening Of Mono- And Bicyclic Compounds For The Production Of Renewable Diesel And Jet Fuel, Matthew J. Kline

Electronic Theses and Dissertations

Thermal DeOxygenation (TDO) is a process that converts organic acids produced from cellulose hydrolysis and dehydration into a low-oxygen bio-oil containing substituted naphthene compounds. The high aromatic content is desirable for gasoline fractions, but middle distillates such as diesel and jet fuel require upgrading via hydrogenation and ring opening to achieve better combustion characteristics. Previous research has demonstrated that TDO oil could be hydrogenated over high-surface-area nickel catalysts to improve the combustion characteristics, but the cetane number was still below the specifications.

Multiple supported catalysts were synthesized by ion exchange and incipient wetness impregnation, and the catalysts were characterized by …

Structural, Charge Transport, Gas Sensing, Magnetic, Pseudocapacitive, And Electrocatalytic Properties Of Perovskite Oxides., Surendra Bahadur Karki

Electronic Theses and Dissertations

Perovskites are functional materials with the general formula ABO₃ (A = alkali, alkaline earth or lanthanoid cations and B = transition metal or main group cations). These materials are marked by a variety of crystal structures and interesting properties such as colossal magnetoresistance, ferroelectricity, multiferroicity, superconductivity, pseudocapacitance, gas sensing, charge transport, and electrocatalytic properties. The formula of perovskite can be written as AA’BB’O₆, when there is ordering between two cations over A and B-sites. Such compounds are called double perovskite oxides. Some amount of oxygen could be lost from crystal structure without decomposition of the phase. Such …

Computational Rational Design Of Electrocatalysts For Electrochemical Ammonia And Hydrogen Synthesis, Akash Jain

Doctoral Dissertations

The electrochemical hydrogen evolution reaction (HER) and nitrogen reduction reaction (NRR) offer fossil-fuel-free routes for hydrogen and ammonia synthesis, respectively. However, currently, both processes lack suitable electrocatalysts for practical applications. Thus, this dissertation focuses on the computational rational design of HER and NRR electrocatalysts.

HER is most efficiently catalyzed by platinum (Pt), which is expensive. To reduce the catalyst cost, we investigate core-shell nanoparticles of inexpensive tungsten-carbide (WC) and Pt (WC@Pt). Using first-principles density functional theory (DFT) calculations, we compare the suitability of two WC phases, α-WC and β-WC as support materials for Pt overlayers. We dope WC with titanium …

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, …

Understanding The Photodegradation Mechanism Of Gaseous Acetaldehyde Over Bi2wo6 – Modified Znwo4 Photocatalyst Under Uv Light Irradiation, Mirabbos Hojamberdiev, Ronald Vargas, Shahlo Daminova, Zuhra Kadirova

CHEMISTRY AND CHEMICAL ENGINEERING

Indoor air quality has a significant impact on human health as people spend more time indoors. As a common indoor air pollutant, acetaldehyde is considered toxic when exposed to it for a prolonged period. The aim of this study is the enhancement of the photocatalytic activity of ZnWO₄ with a monoclinic wolframite structure for degradation of gaseous acetaldehyde by modifying its surface with Bi₂WO₆ layered structure. The mechanisms behind the enhanced photocatalytic activity and the pathways for acetaldehyde photodegradation over the Bi₂WO₆-modified ZnWO₄ photocatalyst are discussed.

Modelling Of Reаctive Distillаtion Process For Etherificаtion Reаction, Adham Norkobilov, Olimjon Mаksudov, Abdulaziz Bаkhtiyorov, Orifjon Zаripov, Abbos Elmаnov

CHEMISTRY AND CHEMICAL ENGINEERING

А reаctive distillаtion system is exаmined to produce for the production of Ethyl tert butyl ether (ETBE) viа etherificаtion of isobutene with ethаnol. Optimizаtion methods using heаt integrаtion аre аlso conducted. The molаr reflux rаtio аnd reboiler duty аre cаlculаted using sensitivity аnаlysis. The bottom streаm with the sаtisfied purity of ETBE is integrаted for heаting the feed streаm to the column. Heаt integrаtion from reаctor heаt to the initiаl feed streаm аnd from bottom streаm of the column to the column inlet streаm with the purpose of аchieving tаrget feed temperаture leаds to high conversion in the reаctive distillаtion …

Design And Fabrication Of Nanostructured Electrodes For Complementary Electrochemical And Photoelectrochemical Water Splitting, Kholoud El Sayed Abousalem

Theses and Dissertations

Designing highly active, durable, and nonprecious electrodes for overall water splitting is of urgent scientific importance to realize sustainable hydrogen production. Accordingly, the need to search efficient energy production systems is of crucial necessity. In this thesis, two various systems for sustainable hydrogen production have been reported using electrochemical and photoelectrochemical pathways. In the first part of the thesis, electrochemical water splitting involving both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has been established. To this end, an innovative approach is demonstrated to synthesize flower-like 3D homogenous trimetallic Mn, Ni, Co phosphide catalysts directly on nickel foam via …

Controlling The Emission Of Volatile Platinum Oxides To The Vapor Phase In Diesel Oxidation Catalysts, Arnab Ghosh

Nanoscience and Microsystems ETDs

Pt-based catalysts are used for the treatment of emissions from vehicles, particularly in Diesel oxidation catalysts (DOCs). Three-way catalysts are treated at temperatures ranging from 950℃-1050℃ while DOCs are aged at 800℃ for 50 hrs. At 800°C, Pt reacts with O₂ to form PtO₂ which has a high vapor pressure and can be transported through the vapor phase. These accelerated aging conditions lead to the formation of large Pt particles causing a loss of catalytic activity. In this thesis, we used model thin-film catalysts that made it possible to quantify the emission of Pt to the vapor phase …

Scale-Up Of Flow-Electrode Capacitive Deionization Method For Hard Water Softening, Noah Henry

Williams Honors College, Honors Research Projects

This study’s purpose is to further document a capacitive deionization design that could be capable of purifying H₂O at a household scale where clean water is otherwise unobtainable in applicable regions of the world. The hypothesis behind this study was continuously larger scaled electrochemical cell-units would increase their water softening capabilities in sustainable fashion. The trend at which performance will scale is currently unknown. The units studied were constructed using graphite plates, anion exchange membranes, cation exchange membranes, and Teflon channels. Three streams, two being CaCl₂ solutions in DI H₂O (one being concentrated with CaCl …

Lignin Valorization Via Reductive Depolymerization Using Promoted Nickel Catalysts And Sub- And Supercritical Methanol, Julia Parker

Theses and Dissertations--Biosystems and Agricultural Engineering

While lignin has been regarded as the most promising renewable feedstock for the sustainable manufacture of aromatic compounds, lignin valorization is necessary to improve the economic viability of biorefineries. Reductive catalytic fractionation (RCF), which combines delignification and lignin depolymerization into a single stage while maintaining the structure and integrity of the cellulose component, has evolved as an effective method for processing biomass. The ability of Cu and Fe to promote the performance of a 20% Ni/alumina catalyst when converting native lignin to alkylphenols by RCF in sub- and supercritical methanol was tested. The effectiveness of lignin extraction as measured by …

Synthesis And Characterization Of Hybrid Catalysts For Fischer-Tropsch Jet Fuel Production, Jack M. Steinagel

Honors College Theses

Climate change is a major issue that our world is facing today. Finding renewable options for current infrastructure is paramount to solving this issue. Fischer-Tropsch synthesis of syngas from gasified biomass can produce renewable fuels that can be used in current conventional combustion engines. In order to make this process more industrially viable, a higher selectivity towards the desired range of liquid hydrocarbon products must be achieved. A novel way to do this is to introduce a catalyst to the Fischer-Tropsch reaction. The catalyst’s physical and chemical properties can promote chain growth of specific hydrocarbons. For the purpose of this …

Ethane Dehydrogenation For Light Olefins Production Over Stable Catalyst, Xiaoyan Wang

Graduate Theses, Dissertations, and Problem Reports

Accompanied by the development of modern industry, the demand for light olefins (e.g., ethylene, propylene, butene, butadiene) increases year by year. Light olefins are important intermediates in producing polymers (Polyethylene, Polypropylene, etc.) and rubber (Styrene Butadiene Rubber, Polybutadiene rubber, etc.). The primary process for the production of light olefins is steam cracking of petroleum liquids (naphtha and distillate fuel oil). It is an energy-intensive process, requiring high temperature (750-850℃) and pressure (1.0-4.5 MPa). Meanwhile, due to undesired side reactions, this process has lowered the efficiency of light olefins production and suffers from severe coking issues. Furthermore, as petroleum liquids become …

Towards A Circular Economy: Liquid-Fed Fast Pyrolysis Of Waste Polyolefin Plastics, Daniel G. Kulas

Dissertations, Master's Theses and Master's Reports

Plastic usage has quickly grown in recent years as plastics have become an essential part of everyday life. Unfortunately, recycling rates have not matched the increased growth, with the majority of waste plastic landfilled. The strategy of circular economy has been proposed to reuse the waste plastic to create new polymers, thus avoiding both landfilling and the use of virgin raw materials. Achieving a circular economy for plastics requires the development of new technologies capable of recycling plastic waste under a circular economy perspective. In this dissertation, a novel liquid-fed fast pyrolysis process is introduced towards achieving a circular economy. …

A Novel Pulsed-Plasma Catalytic Reactor For Dry Reforming Of Methane, Benjamin F. Caithamer

Dissertations, Master's Theses and Master's Reports

Concerns over greenhouse gases have led to an increased interest in the Dry Reforming of Methane (DRM) which produces hydrogen and carbon monoxide from the reaction of two greenhouse gases (CO₂ and CH₄) over a catalyst. Currently, DRM is primarily a catalytic process which operates at temperatures between 700°C - 900°C, and 10 to 20 bar using a 1–1.5 ratio of CH₄/CO₂. Unfortunately, these conditions also promote the water-gas shift reaction, which produces additional CO₂. Catalyst coking and sintering can also be significant problems at these harsh conditions. We have developed …

Biodiesel Production From Castor Oil: Mixing Optimization During Transestrification, Islam M. Al-Akraa

Chemical Engineering

No abstract provided.

A Competent Mwcnt-Grafted Mnox/Pt Nanoanode For The Direct Formic Acid Fuel Cells, Islam M. Al-Akraa, Ahmad M. Mohammad, Moutaz Mamdouh, Yasser M. Asal

Chemical Engineering

No abstract provided.

Effect Of Palladium Loading On Catalytic Properties Of Pd/Gce For The Electro-Oxidation Of Methanol, Formic Acid, And Ethylene Glycol, Islam M. Al-Akraa

Chemical Engineering

No abstract provided.

A Competent Mwcnt-Grafted Mnox/Pt Nanoanode For The Direct Formic Acid Fuel Cells, Islam M. Al-Akraa, Moutaz M. Mamdouh, Yaser M. Asal, Ahmad M. Mohammad

Chemical Engineering

No abstract provided.