Physical Chemistry Commons^™

Atomic Force Microscopic Characterization Of Solid Electrolyte Interphase In Lithium Ion Batteries, Qing-Yu Dong, Yan-Li Chu, Yan-Bin Shen, Li-Wei Chen

Journal of Electrochemistry

In recent years, the rapid growing in the electric vehicle market has raised higher requirement on the lithium-ion batteries (LIBs) performance towards energy density and safety. However, considering the successful development of LIBs techniques in the past 30 years, there is little room left for improving the LIBs performance on the aspects related to the electrode materials, battery structure design and production processes. It is important to pursue more comprehensive fundamental understanding in the entire system and working principle of LIBs. Solid electrolyte interphase (SEI), existing between the electrode material and the electrolyte, has been proved to be an important …

In-Situ Raman Spectroscopic Study Of Electrochemical Reactions At Single Crystal Surfaces, Min Su, Jin-Chao Dong, Jian-Feng Li

Journal of Electrochemistry

Since the 1970s, in-situ spectroscopy (Raman, infrared, etc.) has been used to systematically study the electrochemical interfacial reactions which can provide more information about surface reactions and reveal the mechanisms from microscopic view due to its excellent surface sensitivity and energy resolution. With the development of nano-technology, surface-enhanced Raman scattering effect spectroscopy has made rapid progress. Recently, the emergence of SHINERS provides a good in-situ spectroscopic technique for the study of catalytic reactions on single crystal model electrodes with deterministic surface structure. In this paper, we have summarized the application of SHINERS in the study of …

Encouraging More Frogs In Electrochemistry, Yan-Xia Chen, Jun Huang, Dong-Ping Zhan

Journal of Electrochemistry

No abstract provided.

Research Progresses In Ni-Co-Mn/Al Ternary Concentration Gradient Cathode Materials For Li-Ion Batteries, Chun-Fang Zhang, Wen-Gao Zhao, Shi-Yao Zheng, Yi-Xiao Li, Zheng-Liang Gong, Zhong-Ru Zhang, Yong Yang

Journal of Electrochemistry

Nickel-rich ternary materials with large reversible capacity as well as high operating voltage are considered as the most promising candidate for next generation lithium-ion batteries (LIBs). However, the inferior cycle stability and thermal stability have limited their widely commercial applications. Concentration gradient design of Ni-Co-Mn/Al ternary concentration gradient materials have been extensively studied in the past decade, which can ensure high cycle capacity while maintaining excellent cycle stability. In this paper, the latest research progresses in Ni-Co-Mn/Al ternary concentration gradient materials for LIBs are reviewed. Firstly, we summarize the different synthesis methods of ternary concentration-gradient materials, especially focusing on the …

Preparation And Electrocatalytic Performance Of Nico2O4/Ni Foam For Hydrogen Peroxide Electrooxidation, Wei-Wei Chen, Fei-Fan Zhang, Jia-Liang Du, Yi Wang, Chun-Lin Zhao, Kai Zhu, Dian-Xue Cao, Gui-Ling Wang

Journal of Electrochemistry

The electrodes of Ni foam supported NiCo₂O₄ nanowires were prepared by hydrothermal method, followed by a thermal treatment in air, and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that the NiCo₂O₄ nanowires had a diameter of about 50 nm with a length up to 3 ~ 5 μm. The catalytic performances of the Ni foam supported NiCo₂O₄ nanowires for H₂O₂ electrooxidation were studied by cyclic voltammetry and chronoamperometry. The results show that the Ni foam supported NiCo …

Quantitative Trait Loci (Qtl) Underlying Phenotypic Variation In Bioethanol-Related Processes In Neurospora Crassa, Joshua C. Waters, Deval Jhaveri, Justin C. Biffinger, Kwangwon Lee

Chemistry Faculty Publications

Bioethanol production from lignocellulosic biomass has received increasing attention over the past decade. Many attempts have been made to reduce the cost of bioethanol produc- tion by combining the separate steps of the process into a single-step process known as consolidated bioprocessing. This requires identification of organisms that can efficiently decompose lignocellulose to simple sugars and ferment the pentose and hexose sugars lib- erated to ethanol. There have been many attempts in engineering laboratory strains by add- ing new genes or modifying genes to expand the capacity of an industrial microorganism. There has been less attention in improving bioethanol-related processes …

Electrochemical Studies Of Cobalt(Ii) Diphenylazodioxide Complexes, Lakshmi Balarama, Kylin A. Emhoff, Ahmed M.H. Salem, Jovana Hanna, Mohamed N. Alsabony, Mekki Bayachou, Jerry Mundell, W. Christropher Boyd

Chemistry Faculty Publications

The electrochemical behavior of the unusual cobalt(II) diphenylazodioxide complex salts [Co(az)₄](PF₆)₂ 1 and [Co(bpy)(az)₂](PF₆)₂ 2 has been studied by cyclic voltammetry. Each complex displays two quasireversible redox couples, which are proposed to correspond to a reduction of Co(II) to Co(I), followed by a ligand-based reduction. Irreversible reductions of 1 are observed at more negative potentials, and are proposed to arise from deposition of elemental Co and the decomposition of transiently formed Co(-I) species. Spectroelectrochemical experiments on both 1 and 2, involving electrolytic reduction followed by reoxidation, are consistent with …

Study Of Reaction Dynamics Of Protonated/Deprotonated And Radical Cations Of Guanine In Nucleobases And Nucleosides: Singlet Oxygen Oxidation, C8-Water Addition, Cross-Linking With Lysine And Base-Pair Dissociation, Yan Sun

Dissertations, Theses, and Capstone Projects

Among the four DNA nucleobases, guanine (G) has the lowest oxidation potential and represents a preferential target for oxidation and ionization. This leads to the formation of guanine radical cation (G^•+) in various oxidative environments. Of the biologically relevant oxidants, electronically excited singlet oxygen (¹O₂) exclusively damages the guanine bases and gives rise to mutagenesis, DNA-protein cross-linking and cellular death. Combining our home-made electrospray ionization (ESI) guided-ion-beam tandem mass spectrometer, with reaction potential surface calculations and kinetics modeling, five projects have been accomplished as described below.

In project 1, the reactions of deuterated water …

Computational Modeling Of Charge And Excitation Energy Transfer Dynamics In Complex Environments, Ning Chen

Dissertations, Theses, and Capstone Projects

This thesis describes computational simulations of charge and exciton dynamics and quantum calculations of organic conjugated oligomers. A comprehensive computational study of charge hopping dynamics was conducted for a model of disordered chain of sites coupled to quantum environments. Time-dependent mean square displacement, diffusion constant, and mobility were calculated by three different computational methods for solving the master equation, which validate the accuracy of calculations. Approximate rate kernels were also tested to understand the effects of approximations in representing quantum environments. In addition to the effects of temperature and disorder, different values of the gradient in the site energy were …

Development Of An Electrochemical Immunosensor For Direct Detection Of Acrylamide In Food Samples, Pei Ying Lau

Student Works (2020-2029)

Acrylamide, a potential carcinogen which is mainly found in plant-based food such as potato chips, French fries, bread, biscuit, coffee and coco, after undergoing heating process at temperature above 120°C. The permissible maximum intake of acrylamide is 2.6 μg kg−1 of body weight per day to prevent cancer risk. Due to its neurotoxicity and carcinogenicity, a rapid detection method for acrylamide is strongly needed in food safety concern. Herein, a sample pre-treatment free electrochemical immunosensor was developed based on a displacement assay. In a displacement assay format, an antibody is initially bound to the surface immobilized hapten (analyte analogue) and …

Td-Dft Spin-Adiabats With Analytic Nonadiabatic Derivative Couplings, Nicole Bellonzi, Ethan Alguire, Shervin Fatehi, Yihan Shao, Joseph E. Subotnik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

We present an algorithm for efficient calculation of analytic nonadiabatic derivative couplings between spin-adiabatic, time-dependent density functional theory states within the Tamm-Dancoff approximation. Our derivation is based on the direct differentiation of the Kohn-Sham pseudowavefunction using the framework of Ou et al. Our implementation is limited to the case of a system with an even number of electrons in a closed shell ground state, and we validate our algorithm against finite difference at an S₁/T₂ crossing of benzaldehyde. Through the introduction of a magnetic field spin-coupling operator, we break time-reversal symmetry to generate complex valued nonadiabatic derivative …

In Situ Monitoring Of Catalytic Molecular Transformations On Noble Metal Nanocatalysts Using Surface-Enhanced Raman Spectroscopy, Hui Wang, Qingfeng Zhang, Esteban Villarreal, Hao Jing, Kexun Chen

Journal of the South Carolina Academy of Science

Noble metal nanoparticles have long been of tremendous interest in the nanophotonics and nanocatalysis communities owing to their intriguing size- and shape-dependent plasmonic and catalytic properties. The combination of tunable plasmon resonances with superior catalytic activities on the same noble metal nanoparticle, however, has long been challenging because the research on nanoplasmonics and nanocatalysis deals with nanoparticles in two drastically different size regimes. While tunable plasmon resonances are a unique feature of metallic nanoparticles in the sub-wavelength size regime, heterogeneous catalysis requires the use of substrate-supported sub-5 nm nanoparticulate catalysts. In this mini-review article, we share with the readers several …

A Possible Unaccounted Source Of Atmospheric Sulfate Formation: Amine-Promoted Hydrolysis And Non-Radical Oxidation Of Sulfur Dioxide, Shixian Wang, Xiao Cheng Zeng, Hui Li, Joseph S. Francisco

Xiao Cheng Zeng Publications

Numerous field and laboratory studies have shown that amines, especially dimethylamine (DMA), are crucial to atmospheric particulate nucleation. However, the molecular mechanism by which amines lead to atmospheric particulate formation is still not fully understood. Herein, we show that DMA molecules can also promote the conversion of atmospheric SO₂ to sulfate. Based on ab initio simulations, we find that in the presence of DMA, the originally endothermic and kinetically unfavourable hydrolysis reaction between gaseous SO₂ and water vapour can become both exothermic and kinetically favourable. The resulting product, bisulfite NH₂(CH₃)₂⁺ ∙ HSO …

Nanoscale Colocalization Of Fluorogenic Probes Reveals The Role Of Oxygen Vacancies In The Photocatalytic Activity Of Tungsten Oxide Nanowires, Meikun Shen, Tianben Ding, Steven T. Hartman, Fudong Wang, Christina Krucylak, Zheyu Wang, Che Tan, Bo Yin, Rohan Mishra, Matthew D. Lew, Bryce Sadtler

Electrical & Systems Engineering Publications and Presentations

Defect engineering is a strategy that has been widely used to design active semiconductor photocatalysts. However, understanding the role of defects, such as oxygen vacancies, in controlling photocatalytic activity remains a challenge. Here, we report the use of chemically triggered fluorogenic probes to study the spatial distribution of active regions in individual tungsten oxide nanowires using super-resolution fluorescence microscopy. The nanowires show significant heterogeneity along their lengths for the photocatalytic generation of hydroxyl radicals. Through quantitative, coordinate-based colocalization of multiple probe molecules activated by the same nanowires, we demonstrate that the nanoscale regions most active for the photocatalytic generation of …

Water-Mediated Peptide Bond Formation In The Gas Phase: A Model Prebiotic Reaction, George C. Shields, Ariel Gale, Tuguldur T. Odbadrakh, Tyler Ball

Chemistry Publications

The emergence of life on the prebiotic Earth must have involved the formation of polypeptides, yet the polymerization of amino acids is thermodynamically unfavorable under biologically relevant aqueous conditions because amino acids are zwitterions in solution and because of the production of a water molecule through a condensation reaction. Many mechanisms for overcoming this thermodynamic unfavorability have been proposed, but the role of gas phase water clusters has not been investigated. We present the thermodynamics of the water-mediated gas phase dimerization reaction of glycine as a model for the atmospheric polymerization of amino acids prior to the emergence of biological …

Particle Formation And Surface Processes On Atmospheric Aerosols: A Review Of Applied Quantum Chemical Calculations, George C. Shields, Ariel Gale, Tyler Ball, Tuguldur T. Odbadrakh, Angelini Leonardi, Heather M. Ricker, Juan G. Navea

Chemistry Publications

Aerosols significantly influence atmospheric processes such as cloud nucleation, het- erogeneous chemistry, and heavy-metal transport in the troposphere. The chemical and physical complexity of atmospheric aerosols results in large uncertainties in their climate and health effects. In this article, we review recent advances in scientific understanding of aerosol processes achieved by the application of quantum chemical calculations. In particular, we emphasize recent work in two areas: new particle for- mation and heterogeneous processes. Details in quantum chemical methods are pro- vided, elaborating on computational models for prenucleation, secondary organic aerosol formation, and aerosol interface phenomena. Modeling of relative humidity effects, …

Twenty Years Of Exceptional Success: The MOlecular EDucation And REsearch COnsortium In UNdergraduate Computational ChemistRy (Mercury)” , George C. Shields

Chemistry Publications

The molecular education and research consortium in undergraduate computational chemistry (MERCURY) consortium, established in 2000, has contributed greatly to the scientific development of faculty and undergraduates. The MERCURY faculty peer-reviewed publication rate from 2001 to 2019 of 1.7 papers/faculty/year is 3.4 times the rate of the physical science faculty at primarily undergraduate institutions. We have worked with over 1000 students on research projects since 2001, and 75% of our undergraduate research students have been under-represented in chemistry, either female or students of color. Approximately half of our alumni attend graduate school for the purpose of obtaining advanced degrees in STEM …

Maintaining A High Degree Of Research Productivity At A Pui As Your Career Advances, George C. Shields, Scott E. Feller

Chemistry Publications

In this perspective, two experienced academic administrators who are computational chemists discuss strategies for how to maintain an active research program at a pre- dominately undergraduate institution as your career progresses. More responsibility equates to less time for research, so planning for research to remain a priority is essential. We all have the same amount of time, so figuring out how to use yours bet- ter is the key to remaining active. Professional organizations such as Council on Undergraduate Research, consortia of computational chemists such as Molecular Education and Research Consortium in computational chemistRY and Midwest Undergraduate Computational Chemistry Consortium, …

Instrument And Application Development In Saturation Recovery And Rapid Scan Electron Paramagnetic Resonance, Joseph E. Mcpeak

Electronic Theses and Dissertations

Enhanced signal sensitivity by the use of Rapid Scan (RS) electron paramagnetic resonance (EPR), a technique that allows for much faster magnetic field scans than traditional field-swept techniques, has facilitated improved data acquisition for many types of samples. For example, irradiated fingernails for radiation dosimetry have been studied using RS-EPR, which resulted in substantial decreases in detection limits. Samarium-mediated reduction mechanisms in organic synthesis have been investigated by RS-EPR providing evidence for a radical intermediate. Spectra of organic radicals exhibiting both narrow lines and closely spaced hyperfine interactions have been recorded via RS-EPR. Well-resolved spectra can be recorded at a …

Parahydrogen Hyperpolarized Multi-Nuclear Contrast Agents For Potential Mri Applications, Nuwandi Maduranga Ariyasingha Uragoda Wiyannalage

Wayne State University Dissertations

ABSTRACT

PARAHYDROGEN HYPERPOLARIZED MULTI-NUCLEAR CONTRAST AGENTS FOR POTENTIAL MRI APPLICATIONS

by

NUWANDI M. ARIYASINGHA

December 2020

Advisor: Dr. Eduard Chekmenev

Major: Chemistry (Physical)

Degree: Doctor of Philosophy

There have been numerous studies to develop fast, cost effective hyperpolaried (HP) contrast agents with higher polarization values that can be potentially employed for magnetic resonance clinical imaging. Some of the currently used contrast agents are based on 129Xe hyperpolarized nucleus. However, one of the problems associated with this approach, is the high cost of the produced hyperpolarized contrast agents. In addition, the other important practical problem is that the currently used clinical …

Structural Investigation On The Thermal Degradation Of Aqueous Amines In Post-Combustion Co2 Capture, Jeffrey Alexander Laub

Online Theses and Dissertations

One of the major issues concerning the increase in global temperature is with the elevating levels of CO2 in the atmosphere. Combustion of fossil fuels in power plants is a leading contributor to the elevated anthropogenic CO2 concentration. To help alleviate this issue, the investigation of aqueous amines being implemented for the capture of CO2 in the post-combustion carbon capture (PCCC) in power plants has been a growing interest to chemists. One of the concerns with aqueous amines, is their ability to thermally degrade. Thermal degradation is a prominent aspect for the loss of aqueous amines during the stripper process …

Ni-Au Anodic Nano-Electrocatalyst For Direct Glucose Fuel Cells, Islam M. Al-Akraa, Aya S. Abdulhalim Eng, Yassr M. Asal Mr, Ahmad M. Mohammad Prof

Chemical Engineering

This study aims at the sequential assembling of a nickel oxide (NiOx: cauliflower-like nanostructure, 90 nm) and gold (Au; spherical, 95 nm in an average particle size) onto the GC surface nanocatalyst on a glassy carbon (GC) electrode (will be abbreviated as Ni-Au/GC) for the glucose electro−oxidation (GO); the principal anodic reaction in the direct glucose fuel cells (DGFCs). The charge of the Ni deposition on the GC surface (will be abbreviated as Ni/GC electrode) was initially optimized to obtain the highest catalytic activity toward GO which attained at (339.8 Ag−1) by applying 15 mC in the Ni deposition. Yet, …

Tuning The Activity And Stability Of Platinum Nanoparticles Toward The Catalysis Of The Formic Acid Electrooxidation, Islam M. Al-Akraa, Bilquis A. Al-Qodami, Santosh Sridhar Mysore Dr, R. Viswanatha Dr, Abdul Kareem Thottoli, Ahmad M. Mohammad

Chemical Engineering

No abstract provided.

An Annual Time Series Of Weekly Size-Resolved Aerosol Properties In The Megacity Of Metro Manila, Philippines, Connor Stahl, Melliza Templonuevo Cruz, Paola Angela Bañaga, Grace Betito, Rachel A. Braun, Mojtaba Azadi Aghdam, Maria Obiminda L. Cambaliza, Genevieve Rose Lorenzo, Alexander B. Macdonald, Preciosa Corazon Pabroa, John Robin Yee, James Bernard Simpas, Armin Sorooshian

Physics Faculty Publications

Size-resolved aerosol samples were collected in Metro Manila between July 2018 and October 2019. Two Micro-Orifice Uniform Deposit Impactors (MOUDI) were deployed at Manila Observatory in Quezon City, Metro Manila with samples collected on a weekly basis for water-soluble speciation and mass quantification. Additional sets were collected for gravimetric and black carbon analysis, including during special events such as holidays. The unique aspect of the presented data is a year-long record with weekly frequency of size-resolved aerosol composition in a highly populated megacity where there is a lack of measurements. The data are suitable for research to understand the sources, …

Stimuli-Responsive Gelators From Carbamoyl Sugar Derivatives And Their Responses To Metal Ions And Tetrabutylammonium Salts, Dan Wang, Anji Chen, Joedian Morris, Guijun Wang

Chemistry & Biochemistry Faculty Publications

Carbohydrate-based low molecular weight gelators (LMWGs) are interesting compounds with a variety of applications. In this research, a library of nineteen carbamate derivatives of N-acetyl-D-glucosamine were synthesized and characterized, and several derivatives were found to be effective LMWGs. They formed gels in pump oils as well as mixtures of water with ethanol or water with DMSO. The structures of the carbamoyl chains played an important role in the gelation properties, short chain aliphatic derivatives and phenyl carbamates formed gels in more solvents than certain aromatic and dimeric carbamates. The phenyl carbamate gelator was also selected for the encapsulation of …

Development Of Supported Pd-Based Catalysts For Carbon-Carbon Cross-Coupling And Oxidation Reactions, Mrinmoy Das

Theses and Dissertations

Heterogeneous catalysts are a crucial part of chemistry used for various chemical synthesis stages, pharmaceutical, and environmental applications. The use of nanoparticles or rather nanocatalysts enhances the heterogeneous catalytic applications. Both chemical and physical methods can be used to synthesize nanocatalysts. Chemical synthesis methods require comparatively fewer instruments and can easily synthesize a large amount of nanocatalysts. Nevertheless, chemical synthesis methods require reducing agents and solvents that can be toxic or harmful materials. They often need harsh reaction conditions as well, like high temperature and pressure. On the other hand, physical synthesis methods often require complex instrument setup, but their …

Enhanced Glucose Electrooxidation At Ni-Cu Binary Oxide Nanocatalyst, Islam M. Al-Akraa, Mahmoud M. Abouzaid Eng, Yaser M. Asal Mr, Ahmad M. Mohammad Prof

Chemical Engineering

The aim of this study is to fabricate a nickel (NiOx) and copper (CuOx) oxide nanocatalyst on a glassy carbon (GC) electrode (will be abbreviated as Ni-Cu/GC) for glucose oxidation (GO). A sequential electrodepositon mode was applied to assemble NiOx and CuOx in the fabrication scheme. The optimization of Ni loading on the GC surface (will be abbreviated as Ni/GC electrode) was achieved first to attain the maximum catalytic efficiency in terms of the specific current toward GO. This (409 Ag1)was obtained by applying 15 mC/cm2 in the deposition of Ni. However, unfortunately the NiOx/GC could not support a long-term …

Development Of Novel Adsorbent For Industrial Waste Water Treatment, Islam M. Al-Akraa, Hassan M. Shehata Eng, Dalia A. Ali Eng., Hoda A. Elsawy Dr

Chemical Engineering

The main objective of this research project is to perform some experimental procedures to inform the ability of the novel adsorbent used in this project. The chemical modification of the adsorbent is the chemical oxidation of pure powder chitosan using some specific redox pairs which are potassium dichromate and sodium bisulphite. After preparing the modified chitosan, there are some parameters that must be discussed during the adsorption process. The first parameter is the time parameter, showing experimentally the optimum time for adsorption under certain conditions by collecting values of absorbance and concentration of thymol blue adsorbed after the process from …

Singlet Oxygen Generation By Porphyrins And Metalloporphyrins Revisited: A Quantitative Structure-Property Relationship (Qspr) Study, Andrey A. Buglak, Mikhail Filatov, Althaf M. Hussain, Manabu Sugimoto

Books/Book chapters

state followed by formation of singlet oxygen (1O2), which is a highly reactive species and mediates various oxidative processes. The design of advanced sensitizers based on porphyrin compounds have attracted significant attention in recent years. However, it is still difficult to predict the efficiency of singlet oxygen generation for a given structure. Our goal was to develop a quantitative structure-property relationship (QSPR) model for the fast virtual screening and prediction of singlet oxygen quantum yields for pophyrins and metalloporphyrins. We performed QSPR analysis of a dataset containing 32 compounds, including various porphyrins and their analogues (chlorins and bacteriochlorins). Quantum-chemical descriptors …

Correlating The Physicochemical Properties Of Magnesium Stearate With Tablet Dissolution And Lubrication, Julie L. Calahan

Theses and Dissertations--Pharmacy

Magnesium stearate (MgSt) is the most commonly used pharmaceutical excipient and is present in over half the tablet formulations on the market. In spite of its popularity as an effective lubricant, it has been repeatedly recognized that there is significant variability between MgSt samples, which can cause inconsistent lubrication between batches of MgSt. The hypothesis of this research is that the batch-to-batch variability in tablet lubrication and dissolution observed in tablet formulations containing different MgSt samples can be correlated with differences in MgSt physicochemical properties (fatty acid salt composition, crystal hydrate form, particle size and surface area). Developing correlations between …