Chemistry Commons^™

Investigation Of Space Charge Effects On Co2 Electrocatalytic Reduction On Gd-Doped Ceria Via Scanning Kelvin Probe And Model-Based Bayesian Analysis, Alejandro Mejia

Graduate Theses, Dissertations, and Problem Reports (ETD)

In studying novel energy conversion and storage systems, such as high-temperature electrolysis, numerous underlying fundamental physical processes remain unclear or inadequately understood. Among these, the modeling and comprehension of surface reaction mechanisms, coupled with the intricate effects of space‑charge interfaces, remains an unclear and challenging area of research.

The work of this dissertation involves the development of a 2D finite element analysis model, leveraging the robust MOOSE framework from INL. This model, featuring inhomogeneous defect thermodynamics for near-surface chemistry, formulated through Poisson‑Cahn variational theory, has been exploited for studying the electrocatalytic reduction of CO₂ on gadolinia doped ceria. The …

Building Smart Textile Sensors From Bottom-Up: Chemically Precise Self Assembled Materials On Textiles As A Modular Platform For Electroanalysis, Lori-Ann Williams

Dartmouth College Master’s Theses

In this present work, we explore the metallization of textiles and sutures for the development of a wearable portable modular platform technology for non-invasive wound healing monitoring. Currently technology for the metallization of nonconductive materials have been mainly on a 2D surfaces which restricts the bulk metallization of textile surfaces which require specialized equipment and operators which are costly, energy ineffective, and prevents miniaturization. Metallization of nonconductive fabrics are achieved through a conventional electroless deposition of copper nanoparticle species on 3D surfaces to create electrodes. These conductive textiles and sutures were characterized by pXRD, ATR-IR, SEM-EDS, and XPS and were …

The Surface Chemistry And Binding Interactions Of Lignin With Polymer-Encapsulated Gold Nanoparticles Acting As Model Microplastics, Oluwaseun Ayodeji Akinsola

All Master's Theses

This study investigates the surface chemistry and molecular-level interactions between lignin, a special type of natural organic matter, and polymer-capped gold nanoparticles, shedding light on the strength of adsorption between lignin and nanoscale polymer surfaces. Specifically, the study presents a variety of nanoscale polymer surfaces displaying different charged functional groups, using layer-by-layer assembly of three polyelectrolytes (polyallylamine hydrochloride (PAH)), polyacrylic acid (PAA), and poly(diallyldimethylammonium chloride (PDADMAC)) on 90 nm citrate-stabilized gold nanoparticles (AuNPs). This approach provides a library of polymer-encapsulated AuNPs for investigating the binding interactions of lignin to nanoscale polymers via spectroscopic techniques. ζ-potential, dynamic light scattering (DLS), …

Mechanisms Of Dendritic Shorting In Lithium Metal Batteries With Li7la3zr2o12 Solid Electrolytes, Lukas Karapin-Springorum

Pomona Senior Theses

Energy storage will play a crucial role in efforts to mitigate the effects of climate change caused by greenhouse gas emissions from human activity. Lithium metal batteries using solid electrolytes like Li₇La₃Zr₂O₁₂ have higher energy density than lithium-ion batteries, which may enable a more rapid and complete electrification of transportation. However, lithium metal batteries suffer from undesirable short-circuiting when metallic lithium deposits connect the two electrodes. It has been debated whether these lithium dendrites generally grow directionally from the anode or are generated by the reduction of lithium ions inside the solid electrolyte, …

B(C₆F₅)₃ Co-Catalyst Promotes Unconventional Halide Abstraction From Grubbs I To Enhance Reactivity And Limit Decomposition, Austin W. Medley, Diya Patel, Calvin Utne, Trandon A. Bender

Chemistry & Biochemistry Faculty Publications

Ruthenium based Grubbs metathesis has become a commonplace reaction for synthetic chemists. Development of new generations of catalysts evolving from Grubbs I (GI) have led to greater stability, functional group compatibility, and superior reactivities. However, these advancements lead to increased costs. To this end, we report here how the addition of the commercially available tris(pentafluorophenyl)borane Lewis acid, which has become a common place catalyst in its own right, leads to enhanced reactivity of GI. Moreover, the increased reactivity arises via halide abstraction rather than traditional phosphine dissociation, providing ring-opening metathesis polymerization products that are divergent from those synthesized without the …

Lessons Learned From Laboratory Study And Field Application Of Re-Crosslinkable Preformed Particle Gels Rppg For Conformance Control In Mature Oilfields With Conduits/Fractures/Fracture-Like Channels, Baojun Bai, Thomas P. Schuman, David Smith, Tao Song

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

This Paper Surveys the Role of Re-Crosslink able Preformed Particle Gels (RPPG) in Addressing Conformance Challenges within Mature Oilfields. Despite Widespread Preformed Particle Gel (PPG) Application in 15,000+ Wells, their Limitations in Sealing Fractures and Conduits Prevalent in Mature Reservoirs Have Driven the Development of RPPG Formulations. Synthesized in Various Sizes from Micrometer to Millimeter Levels, These Environmentally Friendly RPPGs Are Tailored for Diverse Reservoir Conditions. Findings Showcase the Successful Laboratory-Scale Creation and Upscaling of RPPG Products, Offering Adaptability to Temperatures from 20 to 175°C, Customizable Sizes, Swelling Ratios (5 to 40 Times), and Re-Crosslinking Times Spanning Minutes to Days. …

Solar Enhanced Oxygen Evolution Reaction With Transition Metal Telluride, Harish Singh, Taishi Higuchi-Roos, Fabrice Roncoroni, David Prendergast, Manashi Nath

Chemistry Faculty Research & Creative Works

The Photo-Enhanced Electrocatalytic Method of Oxygen Evolution Reaction (OER) Shows Promise for Enhancing the Effectiveness of Clear Energy Generation through Water Splitting by using Renewable and Sustainable Source of Energy. However, Despite Benefits of Photo electrocatalytic (PEC) Water Splitting, its Uses Are Constrained by its Low Efficiency as a Result of Charge Carrier Recombination, a Large overpotential, and Sluggish Reaction Kinetics. Here, We Illustrate that Nickel Telluride (NiTe) Synthesized by Hydrothermal Methods Can Function as an Extremely Effective Photo-Coupled Electrochemical Oxygen Evolution Reaction (POER) Catalyst. in This Study, NiTe Was Synthesized by Hydrothermal Method at 145°C within Just an Hour …

Corrosion Inhibitors: Mitigating The Degradation Of Rebar, Jake R. Hughes

Williams Honors College, Honors Research Projects

Our conjecture was twofold: first, that two compounds historically used as food preservatives could act as environmentally friendly inhibitors against rebar corrosion, and second, that molecular properties have a quantifiable influence on inhibition efficiency (%IE). To evaluate the two compounds, cyclic potentiodynamic polarization was used to determine corrosion current density (i_corr) and %IE. The “green” inhibitor candidates included sodium metabisulfite and ascorbic acid, which yielded maximum %IE values of -123900% and 91%, respectively. Results indicated that sodium metabisulfite is not a suitable inhibitor, while ascorbic acid showed potential to extend reinforced concrete’s design life without posing health or …

Hybridization Kinetics Of Four-Way Junctions Localized On A Dna Scaffold, Katherine N. Taylor

Honors Undergraduate Theses

DNA computing is an ever-growing field with scientists trying to design structures that optimize logic gate communication to develop fast, biologically compatible, computational structures. We hypothesize that by using the principles of DNA computing, it is possible to design a DNA tile capable of studying localized DNA hybridization that can differentiate between oligonucleotides of different structural conformations. This includes synthetically manipulating DNA into a nanostructure that can perform Boolean logic functions to calculate the different rates of hybridization. To test our hypothesis, we designed a DNA Tile that incorporated a 4WJ using YES logic. Linear and hairpin single-stranded (ss) DNA …

Change Of Metal Oxidation State At High Temperature, Impact Of Temperature And Reactive Gases, Yegor Nikitin

Dissertations and Theses

The fundamental understanding of gas-solid reactions enables a wide range of applications to be developed and improved. Specifically, the use of metal-based materials is critical to ensuring robust, safe, and long-term operations. For example, in power systems where boilers are used to generate steam for heat or electricity generation the use of stainless metal alloys is critical to allow high quality steam to be produced in a very harsh environment. Alternatively, in catalysis, the use of metal doped heterogeneous catalysts are essential in achieving selectivity and conversion performance for chemical synthesis to emissions abatement. Typically, these metal alloys must withstand …

Molecular-Level Design Of Heterometallic Precursors For Rechargeable Battery Cathode Materials, Yuxuan Zhang

Electronic Theses & Dissertations (2024 - present)

The synthetic methods for rechargeable battery cathodes are rapidly evolving along with the continuous advancement of the materials themselves. Utilizing precursors for the synthesis of Li- and Na-ion cathode materials are known to ensure a phase-pure product with isotropic element distribution, thereby further enhancing the electrochemical properties of the cathode material. As more cathode materials with complex compositions continue to emerge, the strategies for designing the corresponding precursors are also getting diversified. One of the most promising directions is the employment of single-source precursors (SSPs), defined as molecules that contain all necessary elements in the proper ratio and decomposable under …

Stabilizing Bulk Lead-Free Tin Halide Perovskites, William Rice

Electronic Theses & Dissertations (2024 - present)

Tin halide perovskites are a growing candidate in the semiconducting materials field due to their band gap, and ability to be doped (specifically p-type doped). Halide perovskites are sensitive to light and air which causes the degradation of the material from its preferred cubic perovskite lattice. This thesis introduces a way of stabilizing bulk CsSnCl3 through the Goldschmidt tolerance factor. It will also introduce potential new ways to p-type dope halide perovskites. We attempted to p-type dope our halide perovskite by substitutional, interstitial, and vacancy doping to increase the carrier concentration to compete with current perovskites. During our trials of …

Gas Evolution Of A Nickel-Zinc Cell, Niklas Landgraf

Graduate Theses/Dissertations

Batteries are a foundational technology in some of the industries most essential to humanity. Often, their advancement to achieve better performance impacts human lives positively. There are a wide variety of battery chemistries that have been utilized, and the differences in their properties have caused them to be used in many distinct niche applications. Nickel-Zinc (NiZn) batteries are desirable because of their recyclable materials, high cell voltage, and high cycle-life. However, it experiences undesirable shape-change of its electrode materials and gas production due to the electrolysis of the aqueous electrolyte. These can lead to a decrease in capacity over many …

Compton Scattering Of Mammographic Soft X-Ray Beams By Alkali And Transition Metal Salt Filters Produce X-Ray Interference Zones That May Have Treatment Potential For Localized Cancer Lesions, Subhendra N. Sarkar, Eric Lobel, Sabina Rakhmatova, Derbie Desir, Somdat Kissoon, Daler Djuraev, Katie Tam

Publications and Research

In breast x-ray imaging scattered radiation adds 50% of harmful radiation dose from anisotropic Compton scattering mechanism. We have been working with double layered inorganic salt materials that can induce Compton scattering to the incident mammographic x ray beams (in 20-30 kVp range) with adequate isotropy (angular control). Typically metal nitrates and alkali halide salt layers are shown here to cause low energy radiation interference zones with high and low photon intensities and local flux heterogeneity in terms of flux covariance. Spatial variation of low energy photon flux creates concentrated and sparse radiation zones that may be used to induce …

Addressing The Effects Of Counterion Size On The Properties Of Electrochemically Doped Conjugated Polymers, Kyle Baustert

Theses and Dissertations--Chemistry

Conjugated polymers (CPs) are an emerging class of materials that are attractive for many applications due to their low cost, flexibility, and ease of processing. Both chemical and electrochemical doping of CPs is done to alter important properties such as their electrical conductivities and optical absorbances. This ability to tune their properties allows for their use in devices such as organic electrochemical transistors (OECTs) for biosensing and bioelectronics, electrochromic devices for color changing windows, as well as wearable thermoelectrics to use body heat to power wearable electronics. There are several factors that can influence the properties of doped CPs including …

Single-Atom Catalysts For Electrochemical Energy Conversion: Copper Single-Atom Catalyst For Oxygen Reduction Reaction And Quantification Of Site Density By Co Stripping Voltammetry, Dawatage Perera

Theses and Dissertations--Chemistry

Fuel cells are considered a promising technology for achieving cleaner and more sustainable energy production and utilization. However, one of the current major challenges is the economic viability associated with the extensive use of Pt group metal (PGM) catalysts, particularly on the cathode side. Therefore, non-PGM single-atom catalysts (SACs) have received considerable attention as alternatives for PGM catalysts in the oxygen reduction reaction (ORR), which occurs at the cathode of the fuel cell. Among various SAC structures, the non-PGM/nitrogen-doped carbon-based structure (M-N-C) stands out for its excellent ORR performance.

Chapter 2 illustrates the use of copper metal in place of …

Effect Of Π-Conjugated Ligands And A* Site Organic Cations On The Energetic Properties And Photovoltaic Performance Of Metal Halide Perovskites, Harindi R. Atapattu

Theses and Dissertations--Chemistry

Metal halide perovskites have gained interest in optoelectronic applications such as photovoltaics, lasers, LEDs, transistors, and photodetectors due to their excellent semiconducting properties considering their low cost. Metal halide perovskite (HP) photovoltaics have rapidly increased in power conversion efficiency (PCE), which now exceeds 25%. HPs have gained attention in these applications due to their high tolerance towards defects, long charge carrier diffusion lengths, high charge carrier mobility, high optical absorption, and bandgaps that are tunable over a large range. Even though HP photovoltaic PCEs are improved these are still not commercially available due to them showing lower stability and energy …

Understanding Of Processing Additives Influence In Tin Halide Perovskites: Chemistry, Defect, And Photovoltaic Performance, Syed Rahmath Ullah Joy

Theses and Dissertations--Chemistry

Metal halide perovskite semiconductors have attracted much interest for various applications, such as solar cells, light emitting diodes, photodetectors, and lasers, due to their excellent optoelectronic properties. Photovoltaic cell development is centered on Pb-based perovskites, which have equal photovoltaic performance compared to the traditional silicon photovoltaic. But concerns arising from the usage of toxic lead metal have motivated the research community to seek an alternative derivative. Among those, tin halide perovskites show much promise as an alternative to Pb-counterparts due to their ideal bandgap for single junction photovoltaics and similar optoelectronic properties to Pb perovskites. Nevertheless, tin perovskites suffer from …

Synthesis, Functionalization, And Application Of Polymeric Membrane Blends Of Polysulfone, Poly-Ether Ether-Ketone, And Natural Fiber Additive Biochar For Optimal Water Treatment., Abelline Katusiime Fionah

Theses and Dissertations--Chemistry

According to the Center for disease control (CDC), an estimated 1.7 to 2.2 million persons die from waterborne diseases annually. The majority of individuals dying from diseases resulting from unsafe drinking water, such as diarrhea and gastroenteritis, are children. This has in turn created a global water crisis. Different methods have been developed to treat contaminated water in response to the global water crisis such as adsorption, filtration, ozonolysis, catalysis, etc. Of the methods available, filtration via polymeric membranes has been one of the most successfully applied. A membrane is a thin semi-permeable barrier (often made of a polymer) used …

Stability Of Organic Metal Halide Perovskites, S S M Tareq Hossain

Theses and Dissertations--Chemistry

Perovskites have emerged as a promising candidate for low-cost production of solar cells. However, the most critical barrier for commercialization of perovskite solar cells (PSCs) is the inadequate stability of the organic metal halide perovskites (OMHPs). The degradation of OMHPs is induced by light, heat, air, and electrical bias. The known degradation pathways involve the oxidation of I- and Sn2+, dissolution of perovskites by moisture, irreversible reactions with water, ion migration, and ion segregation. To improve the stability of OMHPs various methods are adopted, such as additive engineering, perovskite surface treatment, and composition engineering. Surface ligands are used on top …

Fundamental Studies Of Optical Properties And Electrocatalytic Properties Of Low Dimensional Nanomaterials Carbon Nano Dots And 2d Transition Metal Dichalcogenides, Nadeesha Kothalawala

Theses and Dissertations--Chemistry

Low dimensional nanomaterials are widely used in a variety of applications such as opto-electronics, energy production and storage, and bio-medical applications due to their unique optical, catalytic, electronic, and mechanical properties. Most of the nanomaterials offer a plethora of modifications in their structure, composition, morphology, and dimensionality that can lead to the manipulation of their physiochemical properties. This dissertation presents insight into two types of compelling nanomaterials: carbon nanodots (CND) and transition metal dichalcogenides (TMD), investigating their optical and electrocatalytic properties respectively.

Carbon nanodots (CND) are a promising class of photoluminescent nanomaterials that hold a significant potential in many optoelectronic …

Investigating The Behavior Of Redox–Active Organic Molecules In Electrochemical Energy Storage Through Experiment–Guided Computational Simulations, Anton Perera

Theses and Dissertations--Chemistry

The long–anticipated implementation of using renewable sources such as solar and wind to meet the world’s energy demand is still limited by not having appropriate grid–level energy storage systems on a global scale. When considering grid–scale energy storage solutions, environmental concerns, and techno–economic viability play a crucial role in the practical implementation of such technology. To address this, redox–active organic molecules (ROMs) have been explored for many uses including serving as redox–active molecules in redox flow batteries (RFBs) and providing overcharge protection in lithium–ion batteries (LIBs).

Nevertheless, in order to be a major player in electrochemical energy storage, further optimization …

Data-Driven Modeling Of Oxygen Kinetics In La0.6sr0.4co0.2fe0.8o3−Δ (Lscf) For High-Temperature Reduction Of Co2 In An Electrolysis Cell, Ferron Campbell

Graduate Theses, Dissertations, and Problem Reports (ETD)

Electrolysis systems are critical to several societal applications, particularly energy storage and conversion. Developing these systems requires a detailed knowledge of the chemistry and thermodynamics of the materials used in the electrolysis cell. This work focuses on using embedded scientific machine learning as an efficient way to build an interpretable model for the reaction and transport kinetics in the LSCF electrode, whose performance directly influences the electrolysis system’s performance. The models developed in this study are trained using the publicly available machine learning package, FoKL-GP. This package incorporates a robust Gibbs sampler that employs a forward variable selection process to …

Concentration Effects Of Ytterbium(Iii) Ions On The Physical, Structural, Thermal, And Optical Properties Of Barium Phosphate Glasses, Richard Amesimenu

College of Graduate Studies: Theses & Dissertations

Ytterbium(III)-doped glasses are widely known for their application in near-infrared (NIR) lasers and nowadays attract attention for solar spectral conversion in photovoltaic cells. In this study, the effects of ytterbium(III) concentration on the physical, structural, optical, and thermal characteristics of Yb-doped phosphate glasses were investigated. The glasses were synthesized using the melt-quenching technique with nominal compositions of 50P₂O₅:(50 – xBaO):xYb₂O₃ (x = 0, 0.5, 1.0, 2.0, 3.0 and 4 mol%). The properties were then examined by density and related parameters, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform-infrared …

Phosphorescent Carbon Dots Doped Silica Nanomaterials Via Microwave-Assisted And Modified Stöber Methods For Anti-Counterfeiting And Biosensing, Weichao Liu

Dissertations and Theses

Phosphorescent materials are essential in bioimaging, anti-counterfeiting, and other applications due to their prolonged light emission. However, current phosphorescent materials face challenges such as complex synthesis, high costs, and instability. Carbon dots (CDs), with size less than 10 nm, are a promising alternative due to their biocompatibility, tunable optical properties, and simple synthesis. This thesis explores the synthesis of CDs using ethylenediamine (EDA) and phosphoric acid via a microwave-assisted method, followed by silica encapsulation using a modified Stöber process to form CDs@SiO2, aiming to enhance their stability and optical properties. Optical characterization showed a slight blue shift in the excitation …

Designing Fluorescent Moscs For Potential Applications In Illicit Drugs Detection, Robyn Nicole Cook

Dissertations and Theses

Illicit and hazardous substances pose a serious effect on the human body which can create longer-term issues on the mental and physical health which potentially lead to fatalities. Current methods for detecting illicit substances include analytical techniques like mass spectrometry (MS) and gas/liquid chromatography (GC/LC) which are known for accuracy and sensitivity. However, these instruments are bulky, costly, time-consuming, and require highly trained personnel. An alternative approach to overcoming these limitations is to employ nanostructured molecule-based chemical sensing technologies that are user-friendly, portable, and cost-effective with the sensitivity for detecting illicit substances. One such candidate is metal-organic super-containers (MOSCs), which …

Real-Time Spectroscopic Ellipsometry For Flux Calibrations In Multi-Source Co-Evaporation Of Thin Films: Application To Rate Variations In Cuinse₂ Deposition, Dhurba R. Sapkota, Balaji Ramanujam, Puja Pradhan, Mohammed A. Razooqi Alaani, Ambalanath Shan, Michael J. Heben, Sylvain Marsillac, Nikolas J. Podraza, Robert W. Collins

Electrical & Computer Engineering Faculty Publications

Flux calibrations in multi-source thermal co-evaporation of thin films have been developed based on real-time spectroscopic ellipsometry (RTSE) measurements. This methodology has been applied to fabricate CuInSe₂ (CIS) thin film photovoltaic (PV) absorbers, as an illustrative example, and their properties as functions of deposition rate have been studied. In this example, multiple Cu layers are deposited step-wise onto the same Si wafer substrate at different Cu evaporation source temperatures (TCu). Multiple In₂Se₃ layers are deposited similarly at different In source temperatures (TIn). Using RTSE, the Cu and In₂Se₃ deposition rates are determined as …

Understanding Catalyst Design Principles In Transition Metal Mixed Anionic Chalcogenides For Electrocatalytic Energy Conversion, Ibrahim Abdullahi

Doctoral Dissertations

"This research focused on the synthetic design of transition metal mixed anionic chalcogenide catalysts containing various ligand types around the central metal atom (chalcogen anion and chalcogen-based organic ligand) generating diverse crystal structure types applied for water splitting and carbon dioxide reduction reactions (CO₂RR).

A series of catalysts were synthesized starting with isolated metal complexes (ME_n) with a central metal core (M = Co, Ni, Cu, and Cr) through molecular clusters, to bulk nanostructured solids of similar M-E coordination. Bis(dichalcogenoimidodiphosphinato) were employed as ligands in the metal complexes, and anionic chalcogen (E = S, Se, and …

Conversion Of Cellulose To 5-Hydroxymethylfurfural As Sustainable Energy: A Bibliometric Analysis By Vosviewer, Royyan Faradis, Ardiansyah Bagus Suryanto, Irmina Kris Murwani

Journal of Environmental Science and Sustainable Development

The developments of the global economy and society impact resources and the environment. This condition requires an alternative to find new, safe, and sustainable energy types. The conversion of cellulose to 5-hydroxymethylfurfural (5-HMF) has become a significant area of research interest. It has triggered the development of research directions related to biomass and energy because it can be an intermediary source for making polymers, solvents, pharmaceuticals, and biofuels. The primary objective of this study is to give a bibliometric analysis of 1753 reports on the development of research on cellulose conversion to 5-HMF from 1965 to 2021. The data were …

Nitrogen-Doped Graphite Felt On The Performance Of Aqueous Quinone-Based Redox Flow Batteries, Heng Zhang, Li-Xing Xia, Shan Jiang, Fu-Zhi Wang, Zhan-Ao Tan

Journal of Electrochemistry

Modification of electrode is vitally important for achieving high energy efficiency in aqueous quinone-based redox flow batteries (AQRFBs). The modification of graphite felt (GF) was carried out by means of urea hydrothermal reaction, and simultaneously, the effects of hydrothermal reaction time on the functional groups and surface structure of nitrogen-doped graphite felt were studied. The surface morphology and defect, element content and surface chemical state of the modified electrode were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) test, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The electrochemical performance of the modified electrodes was evaluated by cyclic voltammetry, electrochemical impedance …