Physical Chemistry Commons^™

Facile Synthesis Of A Tailored-Designed Au/Pt Nanoanode For Enhanced Formic Acid, Methanol, And Ethylene Glycol Electrooxidation, Yaser M. Asal Mr., Islam M. Al-Akraa Dr, Ahmad M. Mohammad Prof

Chemical Engineering

The recent revolution in nanoscience and global energy demand have motivated research in liquid fuel cells (LFCs) due to their enhanced efficiency, moving flexibility, and reduced contamination. In line with this advancement, a glassy carbon (GC) electrode was modified with platinum (PtNPs) and gold (AuNPs) nanoparticles to fabricate a nanosized anode for formic acid, methanol, and ethylene glycol electrooxidation (abbreviated, respectively, to FAO, MO, and EGO), of the key anodic reactions of LFCs. The deposition sequence of the catalyst’s layers was important where the Au/Pt/GC electrode (in which PtNPs were directly deposited onto the GC surface followed by AuNPs—surface coverage …

Refinement Of Production Grade Biodiesel, Campbell Axt, Robert B. Hughley Jr., Sydney Ninneman, Jillian Turner

The Corinthian

The modified Burton method for the thermal hydrogen-cracking of peanut oil has been investigated in McGill Research Group since 2009. The successful and reliable production of biodiesel has been achieved since 2014. A hydrocarbon with a viscosity similar to Production Grade Diesel will work in modern diesel engines. The current product has a viscosity significantly lower than production grade diesel. The starting material has a viscosity significantly higher than Production Grade Diesel. Current research is investigating methodologies to mix starting material and product to achieve target viscosity.

Influence Of Applied Potential And Metal Ion Concentraion On Metal Electrodeposition At Micron Gap Gold Electrodes, Krista Michel Riggins

Online Theses and Dissertations

Zamborini and Coworkers developed, a simple, low cost, and highly parallel electrochemical approach for fabricating nano-scale (metal/metal) or molecular (metal/polymer or self-assembled monolayer (SAM)/metal) junctions that should be useful in preparing working sensors and molecular electronic devices. The fabrication of metal/metal junctions involves metal deposition on one set of electrodes (E1), where the metal grows and becomes connected to a second set of electrodes (E2) of an Au interdigitated array of electrodes with a 5 µm separation. However, when different metals were deposited, they deposited in different fashions. Ag grew in the form of wires and Palladium deposited in the …

Acue Reflection From A Stem Perspective, Ashley Vizenor

Q2S Enhancing Pedagogy

The following document contains reflections from various activities of the ACUE workshop. Activities pertain to syllabus editing, classroom conduct, and effective teaching practices.

Reaction Mechanism Between Small-Sized Ce Clusters And Water Molecules: An Ab Initio Investigation On CeN+H2O, Rulong Zhou, Yang Yang, Seema Pande, Bingyan Qu, Dongdong Li, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Reactions of small-sized cerium clusters Ce_n (n = 1–3) with a single water molecule are systematically investigated theoretically. The ground state structures of the Ce_n/H₂O complex and the reaction pathways between Ce_n + H₂O are predicted. Our results show the size-dependent reactivity of small-sized Ce clusters. The calculated reaction energies and reaction barriers indicate that the reactivity between Ce_n and water becomes higher with increasing cluster size. The predicted reaction pathways show that the single Ce atom and the Ce₂ and Ce₃ clusters can all easily react with H …

Au60–: The Smallest Gold Cluster With The High-Symmetry Icosahedral Core Au13, Seema Pande, Xingao Gong, Lai-Sheng Wang, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Among coinage metal nanoclusters with 55 atoms, only Ag₅₅^– and Cu₅₅^– are the geometric magic-number clusters, as both exhibit icosahedral symmetry. Au₅₅^–, however, exhibits much lower symmetry due largely to the strong relativistic bonding effect. In this study, we collect a much larger population (>10,000 isomers) of low-energy isomers of Au₅₅^– to Au₆₀^– by using the combined density-functional theory and basin-hopping global optimization method. We also include the spin−orbit effect in the density-functional theory computation to achieve simulated photoelectron spectra in quantitative fashion. Remarkably, we uncover that the …

A Promising Modification Of Pt Surfaces With Cnts For Decreasing Poisoning Impact In Direct Methanol Fuel Cells, Islam M. Al-Akraa Dr., Yaser M. Asal Mr, Aya A. Khalifa Ms.

Chemical Engineering

Direct methanol fuel cells (DMFCs) are clean energy sources that have many applications due to the high energy density of methanol as a fuel. However, this type of fuel cells (FCs) has limitations that are preventing it from being commercialized. One such limitation is the adsorption of intermediates such as CO into the surface of the Platinum (Pt) catalyst during methanol oxidation (MO) which deactivates its active sites, where the reaction is taking place, and leads to poisoning of the electrode over the long term. In this study, multi-walled carbon nanotubes (MWCNTs) have been introduced to the Pt-modified glassy carbon …

Enhanced Electro-Oxidation Of Methanol At Pt-Au Nanocatalyst For Direct Methanol Fuel Cells, Islam M. Al-Akraa Dr., Yaser M. Asal Mr, Ahmad M. Mohammad Prof

Chemical Engineering

In this investigation, a Pt-Au nanocatalyst prepared by the coelectrodeposition of Pt (PtNPs) and Au (AuNPs) nanoparticles is assembled onto a glassy carbon (GC) electrode for efficient methanol oxidation (MO). Several molar ratios between PtNPs and AuNPs have been used and the corresponding catalytic activity towards MO is tracked. The Pt1:Au1 catalyst showed the highest catalytic activity (5 times higher oxidation peak current (Ip) and a 126 mV negative shift in the onset potential (Eonset) toward MO). The catalyst’s morphology, composition and activity are investigated and the ehancement mechanism is recognized.

A Simple And Effective Way To Overcome Carbon Monoxide Poisoning Of Platinum Surfaces In Direct Formic Acid Fuel Cells, Islam M. Al-Akraa Dr., Yaser M. Asal Mr, Sohair A. Darwish Ms

Chemical Engineering

A glassy carbon (GC) electrode modified with multi-walled carbon nanotubes (MWCNTs) and platinum nanoparticles (PtNPs), Pt/MWCNTs-GC, has been introduced for formic acid electro-oxidation (FAO). A similar loading of PtNPs has been conserved for a proper comparison between the Pt/MWCNTs-GC and the unmodified Pt/GC electrodes. The modification with MWCNTs could enhance the loading of PtNPs onto the GC electrode in a way that minimizes its agglomeration and increases its dispersion in the CNTs network. This not only increases the surface area exposed to the reaction but also interrupts the contiguity of the Pt active sites minimizing the adsorption of the poisoning …

Development And Demonstration Of Sampling Techniques For A Chirped Pulse Fourier Transform Microwave Spectrometer, Frank Edward Marshall

Doctoral Dissertations

"With the introduction of the Chirped Pulse-Fourier Transform Microwave Spectrometer in the past decade, it has become possible to rapidly study the rotational spectra of molecules in the gas phase. It is possible to study molecules that are not normally in the gas phase through the use of various sourcing techniques. The development of both the heated nozzle and the laser ablation sourcing techniques allow for the study of liquids and solids, respectively. The design and performance of these sources will be presented in detail and discussed. Additionally, the development of a Multi-Antennae detection scheme, useful in improving overall sensitivity …

Cold Fusion Thirty Years Later, David W. Ball

Chemistry Faculty Publications

In March 1989, the claim of a revolutionary discovery in nuclear energy production galvanized the scientific community. It turned into a classic case of pathological science—and a textbook example of the self-correcting nature of science.

Developing A Basket-Shaped Host Molecule Based On P-Tert-Butylcalix[4]Arene Featuring Urea Groups For Encapsulating Volatile Guest Molecules, Lokugama Widanelage Vidula Priyadarshana

Masters Theses

Molecular baskets are a group of synthetic host molecules which are designed to govern the inclusion of small guest molecules. The basic structural features of basket-shaped host molecules are a cavity for holding a much smaller guest molecule and tunable gates for keeping the guest molecule inside. These types of gates can be tuned by changing temperature, concentration, pH, etc. In this research group's previous study, a molecular basket of cal ix[ 4]arene with carboxylic acid groups was synthesized by functionalizing calix[4]arene's phenol hydroxyl groups with benzyl bromide building blocks. In the study detailed here, 1 , l '-((5-(bromomethyl)-1,3-phenylene)bis(methylene))bis(3-isopropylurea) was …

Applications Of Chemically Modified Nitrogen Doped Carbon, Zirconium Phosphate, Metal Organic Frameworks, And Functionalized Graphene Oxide Nanostructured Adsorbents In Water Treatment, Ayyob Mohammed A Bakry

Theses and Dissertations

Water contaminations by many pollutants, especially heavy metals such as Pb(II), Hg(II), Cu(II), Cd(II), and Cr(VI) pose many public health and environmental concerns as reported in the list of hazardous substances compiled by the US Environmental Protection Agency due to their high toxicity, refractory degradation, and ease of entering food chain. Adsorption by chelating resins is proven to be the most effective method for the extraction of metal ions from polluted and wastewater. However, traditional absorbents such as activated carbon, activated alumina, clay, zeolite, etc., show limited adsorption abilities for these heavy metal ions. The major goal of this thesis …

Stepwise Solvation Of Organic Radical Cations By Ionic Hydrogen And Halogen Bonding In The Gas Phase, Kyle Mason

Theses and Dissertations

The ability to characterize the interactions between ions and solvent molecules plays a critical role in understanding fundamental aspects of thermodynamics in solution chemistry. These interactions are often difficult if not impossible to observe in solution due to the number of solvent molecules far exceeding that of the ions. However, this challenge can be circumvented in the gas phase which enables the isolation and study of reactions between a single ion and single solvent molecule.

Within the field of ion-molecule chemistry are two sub-categories of interactions known as ionic hydrogen bonds (IHBs) and ionic halogen bonds (IXBs). In these interactions, …

Electron Model Based On Helmholtz’S Electron Vortex Theory & Kolmogorov’S Theory Of Turbulence, Florentin Smarandache, Victor Christianto, Robert Neil Boyd

Branch Mathematics and Statistics Faculty and Staff Publications

In this paper, we explore a new electron model based on Helmholtz’s electron vortex and Kolmogorov theory of turbulence. We also discuss a new model of origination of charge and matter.

Synthesis Of Cadmium Arsenide Semiconductor Nanoparticles, Superatomic Silver Clusters, And Silver Coordination Polymers, Sarthak Jashubhai Patel

Legacy Theses & Dissertations (2009 - 2024)

Nanomaterials have chemical, electronic, optical, and other properties distinct from their bulk counterparts. However, the atom-precise synthesis of these materials remains a challenge, leaving open many scientific questions regarding the size regime between nanoparticulate (quantum confined) and bulk character. In this work, efforts toward the synthesis of nanoparticulate and atom-precise metal and semimetal materials are described. The synthesis of II-V semiconductor Cd3As2 having a near-zero bandgap is discussed. Analysis by UV-Vis absorption spectroscopy and powder X-ray diffraction indicate the formation of material with unexpected crystallinity and absorption properties The interaction between the molecular source of As and the solvent was …

Characterization Of Hydrogen Bonding, Halogen Bonding And Argyrophilic Interactions Using Computational Modeling, Sarah Nicole Arradondo

Electronic Theses and Dissertations

Non-covalent interactions govern multiple important chemical processes throughout nature from those within the human body to the complex environment of the atmosphere. Quantum mechanical electronic structure modeling of these relatively weak interactions can provide molecular level insight that can further our understanding of specific macroscopic properties. In the present work different non-covalent interactions are computationally evaluated within four systems. A small prototypical hydrogen bonded system and the various structural motifs that promoted proton transfer within concentrated acid and water clusters are characterized with sophisticated wavefunction based methods and large robust basis sets in order to accurately predict the structures energies …

A Hydrogen-Bond Stabilized Mechanism Of Oxygen Evolution In Photosystem Ii: A Proposed Computational Experiment, Christopher King

Undergraduate Theses, Professional Papers, and Capstone Artifacts

The ability of plants to take in water and release oxygen into the atmosphere is crucial to the survival of life on Earth. During photosynthesis, water is oxidized to O₂ (dioxygen) at the Oxygen Evolving Complex (OEC) of Photosystem II. Structurally, the OEC resembles a box with an open lid, consisting of metal atoms (four manganese and one calcium) bridged by oxygen atoms. The mechanism of action of this complex, however, is not well understood. Various mechanisms have been proposed in recent years to explain how the OEC oxidizes water to dioxygen, but all of these mechanisms contain gaps …

I3: Isomerization Of Isomer Ions, Krisztián Gabor Torma

University of the Pacific Theses and Dissertations

Photoelectron Photoion Coincidence (PEPICO) spectroscopy is a robust tool for elucidating complex unimolecular dissociation mechanisms and for determining thermochemical and kinetic data of gas-phase ion dissociations with high accuracy. In this work, the dissociative photoionization of two sets of isomeric systems were analyzed with PEPICO: 1) C7H7+ ions of toluene (Tol) and 1,3,5-cycloheptatriene (CHT), and 2) two butyl alcohol isomers, 1-butanol and isobutanol. Threshold dissociative photoionization data on these four molecules of interest were collected on the imaging PEPICO apparatus at the VUV beamline of the Swiss Light Source. Data analysis was aided by ab initio calculations and Rice-Ramsperger-Kassel-Marcus (RRKM) …

Roaming Transition States And Highly Accurate Thermochemistry: A Pepico Study Of Two Small Combustion Systems, Kyle John Covert

University of the Pacific Theses and Dissertations

Two small combustion systems, methyl hydroperoxide (CH₃OOH) and 2-propanol ((CH₃)₂CHOH), were studied using imaging photoelectron photoion coincidence spectroscopy (iPEPICO), which combines photoelectron spectroscopy and photoionization mass spectrometry to detect coincident photoelectron-photoion pairs. In the photon energy range of 11.4–14.0 eV, energy selected CH₃OOH⁺ ions dissociate into CH₂OOH⁺, HCO⁺, CH₃⁺, and H₃O⁺ ions. The lowest-energy dissociation channel is the formation of the cation of the smallest “QOOH” radical, CH₂OOH⁺. A statistical rate model fitted to the …

Recent Trends In Stratospheric Chlorine From Very Short‐Lived Substances, Ryan Hossaini, Elliot Atlas, Sandip S. Dhomse, Martyn P. Chipperfield, Peter F. Bernath, Anton M. Fernando, Jens Mühle, Amber A. Leeson, Stephen A. Montzka, Wuhu Feng

Chemistry & Biochemistry Faculty Publications

Very short‐lived substances (VSLS), including dichloromethane (CH₂Cl₂), chloroform (CHCl₃), perchloroethylene (C₂Cl₄), and 1,2‐dichloroethane (C₂H₄Cl₂), are a stratospheric chlorine source and therefore contribute to ozone depletion. We quantify stratospheric chlorine trends from these VSLS (VSLCl_tot) using a chemical transport model and atmospheric measurements, including novel high‐altitude aircraft data from the NASA VIRGAS (2015) and POSIDON (2016) missions. We estimate VSLCl_tot increased from 69 (±14) parts per trillion (ppt) Cl in 2000 to 111 (±22) ppt Cl in 2017, with >80% delivered to …

Exomol Line List - Xxxiv. A Rovibrational Line List For Phosphinidene (Ph) In Its X³Σ¯ And A¹Δ Electronic States, Jonathan Langleben, Jonathan Tennyson, Sergei N. Yurchenko, Peter Bernath

Chemistry & Biochemistry Faculty Publications

A rovibronic line list for the ground (X³Σ⁻) and first excited (a¹Δ) states of phosphinidene, ³¹PH, is computed. The line list is designed for studies of exoplanetary and cool stellar atmospheres with temperatures up to 4000 K. A combination of empirical and ab initio data is used to produce the line list: potential energy curves (PECs) are fitted using experimental transition frequencies; these transitions are reproduced with a root mean square error of 0.01 cm⁻¹. The nuclear Schrödinger equation is solved using these PECs plus Born–Oppenheimer and spin splitting correction terms. …

Solvent Effects And Charge Transfer States In Organic Photovoltaics, Kangmin Liu

Wayne State University Dissertations

Due to their various advantages, including lightweight, flexible, and cheap manufacturing, organic photovoltaic materials have gained enormous research interest. Over nearly two decades, the power conversion efficiency of organic solar devices has increased dramatically. However, it is still low compared to traditional inorganic semiconductors. In order to improve efficiency, a better understanding of the basic thermodynamic properties of the light-to-electricity power conversion process is needed. One nontrivial aspect of organic solar cells is the low dielectric constant, which leads to tightly-bound excitons upon vertical excitations. The separation of electron-hole pairs requires a larger driving force to overcome the Coulombic binding …

Nanostructured Materials For Photocatalysis, Water Treatment And Solar Desalination, Hiran D. Kiriarachchi

Theses and Dissertations

Maintaining a constant supply of clean drinking water is among the most pressing global challenges in our time. About one-third of the population is affected by the water scarcity and it can only get worse with climate change, rapid industrialization, and the population growth. Even though nearly 70 percent of the planet is covered by water, the consumable freshwater content is only 2.5 percent of it. Unfortunately, the accessible portion of it is only 1 percent. Even so, most of the freshwater bodies are choked with pollution. Considering the vast availability of saline water on the planet and the increasing …

Diisopropylammonium Bromide Based Two-Dimensional Ferroelectric Monolayer Molecular Crystal With Large In-Plane Spontaneous Polarization, Liang Ma, Yinglu Jia, Stephen Ducharme, Jinlan Wang, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

In light of their easy processing, light weight and mechanical flexibility, ferroelectric molecular crystal with large spontaneous polarization (P_s) is highly desired for many advanced applications. Herein, we report the first theoretical study of two-dimensional (2D) ferroelectric molecular crystals via ab initio calculations. Specifically, we show that diisopropylammonium bromide (DIPAB) based 2D ferroelectric monolayer molecular crystal with large in-plane P_s of ∼1.5 × 10⁻⁶ μC cm⁻¹ can be achieved by slicing the bulk DIPAB along a specific plane while keeping the space group unchanged. The important roles of hydrogen bonds are …

Novel Adsorbent For Industrial Wastewater Treatment Applications, Islam M. Al-Akraa, Ahmed Y. Zakaria Eng, Dalia A. Ali Eng, Hany A. Elazab Dr, Hoda A. Elsawy Dr

Chemical Engineering

In this study, the hydroxyapatite powder is investigated for both of methylene blue and thymol blue in aqueous solution. The physical and chemical properties of the adsorbent were evaluated systematically using the different techniques including Microsoft Excel programming, linear regression model and also the coefficient of determination. Batch adsorption experiments were conducted to determine the effect of contact time, solution pH, initial dye concentrations, and also the adsorbent dosage on adsorption. The adsorption kinetic parameters confirmed the better fitting of pseudo-second order kinetic model for both of methylene blue and thymol blue. The isotherm data of methylene blue and thymol …

Tools For Understanding Static Structure Factors And Their Application To Simulations Of Liquids, Travis Mackoy

Graduate Research Theses & Dissertations

Molecular dynamics (MD) simulations can be used to compute static structure factors (��(��)) and provide an interpretation of the underlying periodic atomic ordering. MD simulations complement experimentally measured ��(��) by allowing qualitative assignment of peaks to various ordering, such as cation-anion ordering in ionic liquids, via decomposition of ��(��) into partial ��(��). Here we present a method for classifying interatomic distances that allows for quantitative peak assignment and visualization of atoms that contribute most to each peak in calculated ��(��) for soft materials. The method is illustrated by investigating ��(��) for the ionic liquid 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide (C4C1pyrrTFSI), which shows two …

The Impact Of Post Translational Modification On The Aggregation Of The Ss-Amyloid Peptide In The Presence Or Absence Of Lipids, Albert Walton Pilkington Iv

Graduate Theses, Dissertations, and Problem Reports (ETD)

Alzheimer’s disease (AD) is a neurodegenerative condition afflicting 5.7 million Americans with no effective treatments. The pathology of AD is described by the formation of neurotoxic oligomers formed by the self-assembly of amyloid-β (Aβ). The affinity of oligomers for cellular membranes disrupts calcium homeostasis and is believed to be the underlying cause of neurotoxicity; however, due to the metastability of oligomers, it has been difficult to understand their role in membrane interactions and self-assembly. Here we utilize post translational modifications (PTM) to understand the role of specific amino acids on Aβ₄₀-membrane interactions and self-assembly. We employ ThT, AFM, …

Photoluminescent Zirconium Complexes For Visible Light Photoredox Catalysis, Yu Zhang

Graduate Theses, Dissertations, and Problem Reports (ETD)

Early transition metals like zirconium are attractive candidates for the design of luminescent molecules based on earth-abundant elements. Here, a series of zirconium complexes carrying two pyrrolyl-based ligands have been synthesized and characterized. These complexes are photoluminescent upon excitation with visible light and exhibit remarkably long emission lifetimes of hundreds of μs in solution at room temperature. Computational studies using time-dependent density functional theory (TD-DFT) were conducted to identify the nature of the luminescent excited states as mixed intra-ligand/ligand-to-metal charge-transfer (ILCT/LMCT) states. The electrochemistry studies revealed multiple reversible redox events for each zirconium complex. Furthermore, the excited state of the …

Experimental And Modeling Investigation Of The Oh-Initiated Oxidation Of Semi-Solid And Aqueous Saccharide Aerosols, Hanyu Fan

Graduate Theses, Dissertations, and Problem Reports (ETD)

My research focuses on investigating the impact of moisture-induced and oligomer-induced viscosity changes on OH-initiated oxidation of semi-solid aerosols,and the role of gas-liquid interfaces in regulating aqueous aerosol chemistry. Saccharides, which are a major constituent of aqueous atmospheric aerosols, are chosen as model molecules to form highly oxygenated organic aerosols. The experiments are performed using an atmospheric pressure flow-tube reactor with both online VUV-AMS (Vacuum-Ultraviolet Aerosol Mass Spectrometer) and offline GC-MS analysis techniques. The decay rates of saccharide are determined by measuring the loss signal of saccharide in the particle phase as a function of OH exposure (time-integrated total concentration …