Physical Chemistry Commons^™

Theoretical Insights Into The Atomic And Electronic Structures Of Polyperyleneimide: On The Origin Of Photocatalytic Oxygen Evolution Activity, Yi-Qing Wang, Zhi Lin, Ming-Tao Li, Shao-Hua Shen

Journal of Electrochemistry

Polymeric perylene diimide (PDI) has been evidenced as a good candidate for photocatalytic water oxidation, yet the origin of the photocatalytic oxygen evolution activity remains unclear and needs further exploration. Herein, with crystal and atomic structures of the self-assembled PDI revealed from the X-ray diffraction pattern, the electronic structure is theoretically illustrated by the first-principles density functional theory calculations, suggesting the suitable band structure and the direct electronic transition for efficient photocatalytic oxygen evolution over PDI. It is confirmed that the carbonyl O atoms on the conjugation structure serve as the active sites for oxygen evolution reaction by the crystal …

Three-Dimensional Melamine Carbon Sponge/Nai As Cathode Materials For Sodium-Ion Batteries, Qian-Ying Huang, Yue Liu, Zi-Xin Lin, Shu-Yi Zheng, Ting-Ting Mei, Yu-Ting Tang, Ying-He Zhang, Jun Liu

Journal of Electrochemistry

The sodium-iodine (Na-I) battery exhibits significant potential as an alternative energy storage device to the lithium-ion battery. However, its development is hindered by inadequate electrical and thermal stability, as well as the dissolution and shuttling of polyiodide. In this study, we report a preparation method for melamine carbon sponge (MC) via carbonizing a commercially available kitchen sponge. It was revealed that the as-prepared MC, composed of unique self-growing carbon nanotubes, could provide both physical and chemical adsorption capabilities for intermediate polyiodides to improve the electrochemical performance of NaI. Consequently, the NaI/MC electrode effectively minimized polyiodide dissolution and reduced the electrochemical …

Optimization Of Renewable Energy Systems: Comparative Analysis Of Advanced Algorithms And Photovoltaic-Electrolyzer Performance For Cost Reduction And Efficiency Enhancement, Mohamed-Amine Babay, Mustapha Adar, Ahmed Chebak, Mustapha Mabroukia

Journal of Electrochemistry

The increasing demand for cost-effective and efficient renewable energy solutions presents significant optimization challenges in hybrid energy systems. This paper addresses these challenges by conducting a comparative analysis of three advanced optimization algorithms—Lévy Flight Optimization (LFO), Archimedean Optimization (AO), and Quantum Gorilla Optimization (QGO)—to minimize the Total Net Present Cost (TNPC) and Levelized Cost of Energy (LCOE) in hybrid renewable energy systems. The study integrates critical cost parameters such as Capital Expenditure (CAPEX), Operational Expenditure (OPEX), replacement costs, and salvage values into an advanced optimization framework. Three system configurations are evaluated: Wind Turbines and Fuel Cells (WT/FC), Photovoltaic Systems and …

Nuclear Magnetic Resonance Dynamics Of Pyrazole-Litfsi Eutectic Solvents As Promising Electrolytes, Emilia Pelegano-Titmuss, Giselle De Araujo Lima E Souza, Muhammad Zulqarnain, Ramez Elgammal, Thomas Zawodzinski, Steven Greenbaum

Undergraduate Research

Deep Eutectic Solvents (DESs) have emerged as promising candidates to replace conventional organic solvents in various technological applications due to their low vapor pressure, non-flammability, and ease of preparation at low costs. In particular, Type IV DESs, which are composed of metal salts and hydrogen bond donors, are possible replacements for lithium-ion battery electrolytes due to their potential of having high lithium transference numbers. In this study, we investigated solvents of Pyrazole and LiTFSI at varying molar ratios using Fast Field Cycling (FFC) NMR Relaxometry. Notably, the 1:2 LiTFSI: Pyrazole sample shows distinct behavior, exhibiting enhanced relaxation rates for ^{1 …}

A Catalytic Pathway For The Formation Of Cyanobenzene In Nitrogen-Rich Environments And The Spectroscopy Of The Reactive Intermediates, Vincent J. Esposito, Silvia Alessandrini, David Dubois, Ryan Fortenberry

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The catalytic reaction of isocyanobenzene (C₆H₅NC) with NCN⁻ produces cyanobenzene (C₆H₅NC) through various highly stable reactive intermediate species. Nitrogen-rich environments such as Titan’s atmosphere serve as favorable locations to study reaction pathways involving nitrogenated species contributing to organic growth. Formation pathways of cyanobenzene have been characterized, but none with the contribution of anions or phenyl groups. In regions with a high abundance of nitrogen anions, such as Titan’s atmosphere, reactions with species such as NCN⁻ may play a role in the formation of cyanobenzene. Highly accurate computational methods are used …

Complementary Design Of Optical And Photochemical Systems, Joshua Plank

Chemistry Theses and Dissertations

The ability to manipulate chemical systems has been prized through history as the bridge between the macroscopic and microscopic worlds. As an example, the camera obscura has arguably existed since the earliest days of humanity; however, it was the discovery of early silver halide chemistry that lead to the ability to fix these images into the earliest photographs. In modern photolithography employed in electronics manufacturing, the primary resolution limits arise not from the chemistry of the molecules involved, but from the limits of the systems used to project light. Thus, as much as photochemistry advances, optical imaging and projection techniques …

Quantum Chemical Methods And Multiscale Modeling In Computer-Aided Drug Design, Hunter W. La Force

Chemistry Theses and Dissertations

Computer-Aided Drug Design (CADD) leverages a diverse toolkit of computational methods to accelerate the discovery and development of novel therapeutics. Among these, quantum chemical calculations provide unparalleled accuracy in understanding molecular interactions, albeit at a higher computational cost. This accuracy is crucial for identifying and quantifying fundamental interactions that dictate drug efficacy and selectivity, as exemplified by our investigation of ruthenium polypyridyl complexes. These metal-based compounds are model systems for studying covalent coordination bonds between ruthenium and its ligands and noncovalent interactions with DNA and protein targets. Local Mode Vibrational Theory emerges as a powerful lens within this framework, enabling …

Trade-Off Between Limonene & Geraniol-Based Reprocessable And Non-Reprocessable Epoxy Thermosets: Role Of Aliphatic Diamines In Polymer Networks Design, Priyankkumar Kanubhai Patel

Electronic Theses & Dissertations

The growing demand for sustainable materials, driven by environmental concerns and the rapid depletion of fossil fuels, has garnered significant attention in the fabrication of bio-based epoxy thermosets as renewable alternatives to petroleum-derived thermosetting polymers. The present study focuses on the synthesis and characterization of epoxy prepolymer resins derived from limonene and geraniol via a two-step process, followed by the fabrication of thermally cross-linked flexible epoxy thermoset films using various traditional aliphatic diamine curing agents, namely 1,2-ethylenediamine (EDA), 1,4-butylenediamine (BDA), and 1,6-hexamethylenediamine (HDA). Additionally, the incorporation of cystamine, a disulfide-containing diamine, enabled the formation of a covalent adaptable network through …

Enabling New Synthetic Platforms For Aryne Synthesis With Aryl Thianthrenium Reagents, Riley Augustus Roberts

Dissertations and Theses

The enormous importance of aromatic rings in organic molecules cannot be understated. Aromatic rings are present in the majority of pharmaceuticals, agrochemicals, and consumer products. The way in which these rings are arranged and substituted results in a molecule’s unique properties. Because of this, the current limitations of the chemical methods used to synthesize these molecules results in limited structural diversity and thus missed opportunities for the development of value-added products. To this end, this work demonstrates novel methods of aryne synthesis, aryl thianthrenium synthesis and a unique approach to structural scaffold hopping. The approaches presented herein allow for rapid …

Effects Of Structure Of Mepegn Polymers On Hydroxide Conductivity In Anhydrous Anionic Exchange Membranes, Athan M. Gregory

Honors Theses

Anhydrous hydroxide ion (OH-) conducting polymer electrolytes composed of a 1-methyl-pyrrolidinium (1mp) head group linked to various MePEGn (n = 3, 7, 12) backbones were prepared. We have examined the structure of these anion exchange membranes to observe how the structure of the electrolyte affects the observed ionic conductivity. The structural parameters investigated were polymer length, viscosity, fractional free volume (FFV), and volume fraction of PEG (Vf,PEG), and each polymer varied in these properties. Through a comparison of the conductivity and structural parameters in the MePEGn-based anion electrolytes, we have shown that each of these structural properties weakly affects the …

Molecular Insights: Advances In Single Molecule And Single Particle Detection For Analysis Of Chemical, Physical, And Biological Phenomena, James Ethan Batey

Chemistry & Biochemistry Undergraduate Honors Theses

This thesis is focused on recent advancements made in the field of chemical imaging, optical microscopy, and recent developments that have improved spatial, temporal, or spectral resolution or have made certain techniques more accessible and cost effective for their wider adoption. This thesis is organized based on the systems of interest we studied with each new technique. Although, it is important to note that many of the methods here can be used with a multitude of systems even if not explicitly mentioned. The first chapter of this thesis will discuss the current state of chemical imaging, common terminology, and important …

Using Gaussian Process Regression To Learn Thermodynamic Equations Of State With Uncertainty Quantification, Austen T. Lee

Chemical Engineering Undergraduate Honors Theses

This study investigates the use of derivative-informed Gaussian Process (GP) models to estimate thermodynamic behavior across temperature and density by building a Helmholtz-based equation of state. Argon, a stable monatomic gas, was chosen as a case study within the vapor region. The GP model was trained using values of experimentally measurable properties found by taking first and second derivatives of the original potential function. Results show that while the GP model offered uncertainty quantification and informed thermodynamic behavior, it predicted values that deviated from the ground truth depending on the property. The model exhibited high confidence in regions with substantial …

A Study Of Ultrafast, Intense-Field Photodynamics In Carbon Dioxide, Carbon Disulfide, And Select Substituted Benzenes, Joshua Edwin Beck

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The study of the photodynamics of molecules in ultrashort pulses of intense radiation continues to be of interest. Electric field strengths in such pulses can approach or exceed the typical electric field strengths binding the electrons to the nuclear framework (ke/a²₀ ≈ 5 × 10⁹ V/cm). The resulting excitation, ionization, and dissociation of molecular targets is of interest in many areas including attosecond science, femtochemistry, atmospheric science, high harmonic generation, and many other fields.

This dissertation investigates the photoionization and photofragmentation behavior of carbon dioxide, carbon disulfide, and the substituted benzenes nitrobenzene, aniline, as …

A Kinetic Analysis On Hydrolysis And Hydrothermal Conversion Of Cellulose To Dodecane, Joel Nyangoka Onyancha

Electronic Theses and Dissertations

Cellulose, the most abundant biomass on Earth, offers a promising pathway for alternative energy through conversion into alkane hydrocarbons. Traditional methods rely on high temperatures and high-pressure hydrogen, often derived from petroleum. In this study, we investigated the conversion of Microcrystalline Cellulose using hydrogen metal oxides (bronzes) under milder conditions. Following ASTM E3417-24 hydrolysis protocols, we employed hydrogen bronzes with toluene for product extraction. This approach enabled conversion at lower temperatures without pressurized hydrogen. Products were analyzed using Gas Chromatography Mass Spectrometer for identification and Gas Chromatography Flame Ionization Detector for quantification. Our findings revealed the formation of a possible …

Synthesis And X-Ray Characterization Of Nickel Phosphide Nanostructures For Water Oxidation, David Thompson

Graduate Theses and Dissertations

The pursuit of earth-abundant 3d transition metal catalysts for alkaline water electrolysis remains an active area of research. While NiFe layered double hydroxides (LDH) are currently the most active catalysts for the oxygen evolution reaction (OER), doping Ni-based catalysts with phosphorus to form Ni metal phosphides has emerged as a promising alternative. However, the complex crystalline and amorphous phases of NiP_x have hindered their characterization, and the OER mechanism and origin of activity remain unclear. This dissertation aims to elucidate the synthesis, OER performance, and in situ reconstruction of amorphous NiP_x-based nanomaterials, with a focus on in …

Computational Study Of The Proton Transfer In The H7o3+ Cluster, Anna James, Martina Kaledin

Symposium of Student Scholars

Proton transfer (PT) from one molecule to another is among the most studied phenomena in chemistry. PT requires the bond cleavage and the formation of a new one, AH⁺ + B -> A+ BH⁺. In protonated water clusters, such a process consists of the interconversion of hydrogen bonds. Experimentally, such a process can be observed as a significant increase of a dipole moment. However, other vibrational transitions often occur with small changes in the dipole moment while large changes in polarizability. In this work, we study the PT process in a protonated water cluster, H₇O …

Variation Of Membrane Electrode Assembly Catalyst Layer In Unitized Regenerative Fuel Cell, Yollanda Nurcholifah, Dedi Rohendi, Edy Herianto Majlan, Nirwan Syarif, Addy Rachmat, Dwi Hawa Yulianti, Nyimas Febrika S

Journal of Electrochemistry

A unitized regenerative fuel cell (URFC) is a device that may function reversibly as either a fuel cell (FC) or water electrolysis (WE). An important component of this device is the Membrane electrode assembly (MEA). Therefore, this study aimed to compare the performance outcomes of MEA using electrodes with single and three catalyst layers. This study measured Electrochemical Surface Area (ECSA), Electrochemical Impedance Spectroscopy (EIS), X-ray Diffraction analysis (XRD), and X-ray Fluorescence (XRF). Furthermore, the round-trip efficiency (RTE) of the MEA, as well as the performance in FC and WE mode, was measured. In comparison, The ECSA values of Pt-Ru/C …

Computational Analysis Of Proton Conductivity Factors In Grotthuss-Style Mechanisms, Brock Dyer

Physics and Astronomy Honors Papers

The mechanism and fundamental molecular properties involved in proton conduction are discussed. Four calculable properties are presented: the proton affinity, binding energy (between protonated and neutral forms), intramolecular tautomerization barrier, and proton hopping barrier. An overview of the computational methods used in this thesis, including an introduction to the many-body Schrödinger equation and Density Functional Theory, as well as a look at Plane-Wave Density Functional Theory and Gaussian-Type Orbital Density Functional Theory are presented. 4,5-dimethyl-[1,2,3]-triazole is used as a model system, with 10 variations being generated with varying amounts and positions of fluorine substitution on the methyl groups. Preliminary calculations …

Electrocatalytic Nitric Oxide Reduction To Yield Ammonia Over Fe3C Nanocrystals, Sen Lin, Lang Zhang, Tong Hou, Jun-Yang Ding, Zi-Mo Peng, Yi-Fan Liu, Xi-Jun Liu

Journal of Electrochemistry

Nitric oxide (NO), which generally originates from vehicle exhaust and industrial flue gases, is one of the most serious air pollutants. In this case, the electrochemical NO reduction reaction (NORR) not only removes the atmospheric pollutant NO but also produces valuable NH₃. Hence, through the synthesis and modification of Fe₃C nanocrystal catalysts, the as-obtained optimal sample of Fe₃C/C-900 was adopted as NORR catalyst at ambient conditions. As a result, the Fe₃C/C-900 catalyst showed an NH₃ Faraday efficiency of 76.5% and an NH₃ yield rate of 177.5 μmol·h^–1·cm^{–2 …}

Ordering Degree Regulation Of Pt2Nico Intermetallics For Efficient Oxygen Reduction Reaction, Chen-Hao Zhang, Han-Yu Hua, Jun-Hao Yang, Qian Zhang, Chang Yang, De-Li Wang

Journal of Electrochemistry

Alloying transition metals with Pt is an effective strategy for optimizing Pt-based catalysts toward the oxygen reduction reaction (ORR). Atomic ordered intermetallic compounds (IMC) provide unique electronic and geometrical effects as well as stronger intermetallic interactions due to the ordered arrangement of metal atoms, thus exhibiting superior electrocatalytic activity and durability. However, quantitatively analyzing the ordering degree of IMC and exploring the correlation between the ordering degree and ORR activity remains extremely challenging. Herein, a series of ternary Pt₂NiCo intermetallic catalysts (o-Pt₂NiCo) with different ordering degree were synthesized by annealing temperature modulation. Among them, the o-Pt …

Performance Of Co2/H2O Co-Electrolysis In A Flat-Tube Solid Oxide Electrolysis Cell Stack Under Air-Free Environment, Xiao-Hui Zhong, Fei Wang, An-Qi Wu, Bei-Bei Han, Jian-Xin Wang, Wan-Bing Guan

Journal of Electrochemistry

This work investigates the transient performance and stability of CO₂/H₂O co-electrolysis in an air-free environment using a flat-tube solid oxide electrolysis cell (SOEC) stack. The results show that the transient behavior of the stack with and without blowing gas in the air electrode is almost the same. With a current density of 0.67 A·cm⁻²@750 °C, the stack operated for over 200 h under co-electrolysis conditions with no air blowing, and the voltage drop rate of the stack was approximately 0.203%/100 hours. Microstructure analysis reveals significant loss of Ni particles and formation of an insulating …

The Delocalized Toolbox: Tuning Strain, Energetic And Optoelectronic Properties Of Aryl Heterocyclic Scaffolds For Application-Driven Endeavors, Michael Josef Holzmann

Chemistry and Chemical Biology ETDs

This is a three-part dissertation. Part 1 is composed of chapters 1-3 which revolves around the optimization of cyclononyne reactivity towards 1,3 dipolar cycloadditions. Specifically, the synthesis and reactivity of sulfate, sulfamate and sulfamide-bearing cyclononynes will be discussed. Chapters 4-5 comprise Part 2 which addresses optimization of ruthenium olefin metathesis towards reversible activation and inhibition. The mechanism of reversible inhibition mediated by a hexaarylbiimidazole photo-inhibitor will be elucidated. Part 3 consists of chapters 6-8 which describes structure-functional relationship studies on carbon dots and harnessing that insight for sensing applications. Data relating to assays performed with explosive analytes will be analyzed …

Predicting PkA Of Flexible Polybasic Tetra-Aza Macrocycles, Tatum K. Harvey, Kristof Pota, Magy Mekhail, David M. Freire, Donatus A. Agbaglo, Benjamin G. Janesko, Kayla N. Green

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We present physics-based pK_a predictions for a library of tetra-aza macrocycles. These flexible, polybasic molecules exhibit highly charged states and substantial prototropic tautomerism, presenting a challenge for pK_a prediction. Our computational protocol combines CREST/xTB conformational sampling, density functional theory (DFT) refinement in continuum solvent, and a linear empirical correction (LEC). This approach predicts known tetra-aza macrocycle pK_a to within a root-mean-square deviation 1.2 log units. This approach also provides reasonable predictions for the most stable protomers at different pH. We use this protocol to predict pK_a values for four novel, synthetically achievable, …

An Open-Framework Iron-Selenite As Cathode For Li- Ion Batteries, Sutapa Bhattacharya, Aleksandr V. Chernatynskiy, Amitava Choudhury

Miners Solving for Tomorrow Research Conference

No abstract provided.

The Effect Of Nanomorphology As Quantified Via The K‑Index On The Drug Delivery Properties Of Isocyanate-Derived Aerogels, Stephen Y. Owusu, A. B. M. Shaheen Ud Doulah, Vaibhav A. Edlabadkar, Kamden J. George, Chariklia Sotiriou-Leventis

Miners Solving for Tomorrow Research Conference

No abstract provided.

Advanced Mathematical And Computational Methods In Quantum Chemistry, Chao Yin

Chemistry Theses and Dissertations

Wave-function based ab initio calculation methods have been gaining significant atten- tion from chemists due to their ability to provide insights into experimental results. However, their application to large systems is limited by the considerable computational cost involved, especially when dealing with high-dimensional tensors inherent to these calculations. To address these challenges, two primary strategies have been explored in this study. First, advancements in hardware architecture and algorithmic development. Graphics Processing Units (GPUs) have facilitated parallel computation, leading to a significant acceleration of these calculations. In this work, we propose a method for evaluating two-electron repulsion integrals (ERIs)—a key component …

Mechanochemical Reaction Kinetics—A Theoretical Modeling And Experimental Study, Maria Dolores Masso Ramirez

Mechanical & Aerospace Engineering Theses & Dissertations

Mechanochemical reactions represent a class of chemical processes triggered by mechanical energy, widely recognized for their efficiency, solvent-free nature, and environmental benefits. They are increasingly applied in synthetic chemistry, a branch of science focused on creating new chemical compounds through controlled laboratory reactions. However, the mechanisms underlying mechanical activation remain poorly understood, primarily due to the difficulty in quantifying energy transfer during milling, where solid reactants are ground together using a ball mill. This thesis aims to bridge the gap in understanding the relationship between mechanical parameters and reaction kinetics by developing and validating a theoretical framework based on dimensional …

Quantum Effects In Collisional Energy Transfer Simulated Using Mixed Quantum/Classical Theory, Dulat Bostan

Dissertations (1934 -)

Mixed quantum/classical theory (MQCT) was used to study collisional energy transfer between the rotational states of molecules with the focus on reproducing quantum effects related to this process. Namely, rotational energy transfer in the N₂ + O system was studied to replicate quantum interference effects observed as oscillations of scattering cross section as a function of collision energy. Both MQCT code and the full-quantum code MOLSCAT were used for calculations, and results were in excellent agreement with the experiment and the full-quantum infinite-order sudden method from literature. The CO + CO system was used as a case study for …

Experimental And Computational Investigation Of Ethylene Oxide Hydrate And Its Mixed Hydrates With Propane And Isobutane, Adebayo Paul Adeleye

Master's Theses (2009 -)

Gas hydrates represent an important class of crystalline solids, where water molecules form cage-like frameworks that encapsulate gas molecules. They have garnered significant attention for their unique properties and diverse applications in energy and environmental science. This study investigates the formation and vibrational properties of the ethylene oxide (EO) hydrate (structure I, sI) and EO-seeded hydrates of propane and isobutane (structure II, sII) using matrix isolation Fourier-transform infrared (FTIR) spectroscopy, supported by Density Functional Theory (DFT) calculations at the B3LYP/6-311++G(d,p) level of theory. Under low-temperature and low-pressure conditions, EO hydrate was formed by co-depositing a premix of EO and argon …

Study On Dopamine Electrochemical Sensing Based On Au@Mos2, Ning An, Ni Su, Xin-Ran Li, Jian-Yu Liu, Qi-Yan Wang

Journal of Electrochemistry

Dopamine (DA) is a vital neurotransmitter, and accurate detection of its concentration is critical for both clinical diagnostics and neuroscience research. Due to its electrochemical activity, DA is commonly detected using electrochemical methods, which are favored for their simplicity, fast response time, and suitability for in vivo analysis. In this work, a highly sensitive DA electrochemical sensor was developed using an Au@MoS₂ composite, created by modifying molybdenum disulfide (MoS₂) nanosheets with gold nanoparticles through HAuCl₄ reduction, and it was aimed at enhancing DA adsorption and improving detection performance. Scanning Electron Microscopy (SEM), transmission electron microscopy (TEM), …