Physical Chemistry Commons^™

An Aqueous All-Metal Oxide Asymmetric Supercapacitor With High Gravimetric And Volumetric Energy Densities, Xin Jing, Xu Zhang, Wei Wang, Jun-Wei Lang

Journal of Electrochemistry

Only with both high gravimetric and high volumetric energy densities, can supercapacitors find more extensive applications.In this paper, by making good use of the interesting nanostructures and the high packing densities of RuO₂ (nanoshpheres,1.69 g·cm^-3) and Co-Ni oxide (nanoflakes, 2.14 g·cm^-3), the RuO₂//KOH//Co-Ni oxide all-metal oxide asymmetric supercapacitors with high performance were successfully fabricated, which led to the maximum specific capacitance of 217.5 F·g^-1 (412.3 F·cm^-3) and specific energy density of 61.8 Wh·kg^-1 (121 Wh·L^-1) in a cell voltage between 0 and 1.5 V in KOH electrolyte. …

Highly Crystalline Nickel Borate Nanorods As Oxygen Evolution Reaction Electrocatalysts, Xi Xu, Juan Liu, Hua-Zong Wu, Wen-Jie Jiang

Journal of Electrochemistry

Hydrogen energy, a kind of clean and renewable energy, is considered to be the solution to the problems of energy crisis and environmental deterioration. Electrochemical water splitting is an efficient and promising technology for the production of high-purity hydrogen. However, oxygen evolution reaction (OER) at the anode of water electrolyzer limits the efficiency of water splitting due to the high overpotential. Therefore, the challenges still remain for the exploration of highly active, stable and low-cost catalysts with superior activity for OER. Herein, nickel borate nanorods with high crystallinity were prepared via high-temperature calcination. The as-obtained nickel borate nanorods with 2 …

Influences Of Na-Mn Ratio On Electrochemical Performances And Intercalation-Deintercalation Processes Of Sodium Ion In NaXMno2, Yong-Chun Xie, Cheng Wang, Fang Jiang, Yang Yang, Jing Su, Yun-Fei Long, Yan-Xuan Wen

Journal of Electrochemistry

In this work, Na_xMnO₂ was synthesized by a solid-state reaction. The influences of Na:Mn ratio on the structure, morphology and electrochemical performance, and sodium ion intercalation/deintercalation processes were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge test. The prepared Na_xMnO₂ was mainly composed of Na_0.7MnO₂ and Na_0.91MnO₂, and the content of Na_0.91MnO₂ increased with the increase of Na:Mn ratio. However, the activation energy values of surface membrane diffusion, interfacial electrochemical reaction and …

Structure And Thermodynamics Of Polyglutamine Peptides And Amyloid Fibrils Via Metadynamics And Molecular Dynamics Simulations, Riley Workman

Electronic Theses and Dissertations

Aggregation of polyglutamine (polyQ)-rich polypeptides in neurons is a marker for nine neurodegenerative diseases. The molecular process responsible for the formation of polyQ fibrils is not well understood and represents a growing area of study. To enable development of treatments that could interfere with aggregation of polyQ peptides, it is crucial to understand the molecular mechanisms by which polyQ peptides aggregate into fibrils. Many experimental techniques have been employed to probe polyQ aggregation, however, observations from these studies have not lead to a unified understanding of the properties of these systems, instead yielding competing, fragmented theories of polyQ aggregation. This …

Enhanced Acidity Of Acetic And Pyruvic Acids On The Surface Of Water, Alexis J. Eugene, Elizabeth A. Pillar, Agustín J. Colussi, Marcelo I. Guzman

Chemistry Faculty Publications

Understanding the acid–base behavior of carboxylic acids on aqueous interfaces is a fundamental issue in nature. Surface processes involving carboxylic acids such as acetic and pyruvic acids play roles in (1) the transport of nutrients through cell membranes, (2) the cycling of metabolites relevant to the origin of life, and (3) the photooxidative processing of biogenic and anthropogenic emissions in aerosols and atmospheric waters. Here, we report that 50% of gaseous acetic acid and pyruvic acid molecules transfer a proton to the surface of water at pH 2.8 and 1.8 units lower than their respective acidity constants pK_{a …}

Infra-Red Microwave Spectra, Overtones, Degeneracy And Thermal Populations All In One Diagram, Carl W. David

Chemistry Education Materials

An old drawing, which had an error in it, is re-presented (corrected) for understanding the relationships in diatomic vibrational-rotational interactions at the introductory level.

Fabrication Of Mnox/Mwcnts-Gc Nanocatalyst For Oxygen Evolution Reaction, Yaser M. Asal Mr, Islam M. Al-Akraa Dr, Amr M. Arafa Eng.

Chemical Engineering

Manganese oxide (MnOx) and multiwalled carbon nanotubes (MWCNTs) are intended to modify the GC electrode for oxygen evolution reaction (OER). Optimization of MnOx loading is carried out and the deposition of 55 cycles was sufficient to obtain the highest activity toward OER. The stability of the catalyst is enhanced by the addition of MWCNTs. As a result, an amount of 22 kWh/Kg of O₂ of energy is saved. Several techniques including cyclic voltammetry, linear sweep voltammetry, chronoamperometry, chronopotentiometry, field-emission scanning electron microscopy, and energy dispersive X-ray spectroscopy will be combined to track the catalyst activity and to determine its …

Novel Relative Spontaneous Ignition Temperature Determination Using Carbon Dioxide Onset With Sta/Ir, Antonio David Trevino

Electronic Theses and Dissertations

Simultaneous thermal analysis, coupled with infrared spectroscopy (STA/IR), was utilized to monitor the evolution of gaseous products during the thermal degradation of samples from Triadica sebifera (Chinese tallow), Ligustrum sinense (Chinese privet), and Ilex vomitoria (yaupon) plants. Identification of carbon dioxide was successful with a spectral match of 90.2 percent and further used in the determination of relative spontaneous ignition temperature, or RSIT. The RSIT value during the growing season for Chinese tallow, Chinese tallow stem, Chinese privet, and Yaupon were 208.4°C, 250.3°C, 210.1°C, and 232.3°C respectively. During the dormant seasons, the values for Chinese tallow stem, Chinese privet, and …

Modern Electronic Structure Theory: The Search For Chemical Accuracy, Jonathan Prince

Boise State University Theses and Dissertations

Electronic structure theory has progressed significantly within the last few decades, venturing far from the early days of the Hartree-Fock self-consistent field method. Modern electronic structure theory focuses on compound methods, which operate under the idea that we can take a lower level of theory computation (typically, a result from Hartree-Fock, Configuration Interaction, Coupled Cluster or Moller-Plesset perturbation theory) and add in higher level of the theory corrections such as extrapolations to the infinite basis set limit, as well as, relativistic effects.

Using the Gaussian-n, Complete Basis Set and Weizmann compound methods, we were able to provide theoretical evidence to …

Synthetic And Theoretical Studies For Cyclization Reactions To Form C-C And C-N Bonds, Nicholas Jentsch

Dissertations

Natural product total synthesis provides an alternative method for obtaining medicinally relevant compounds in a more efficient process with higher yields than what nature can provide. Natural products pose significant synthetic challenges due to the unique heterocyclic skeletons with fused and spirocyclic ring systems. Therefore, it is paramount to develop efficient reaction methodologies targeting substructures such as cyclic ureas and spiro[4.5]decanes which are prominent among marine natural products and Lycopodium alkaloids, respectively. Presented here is a compilation of research seeking to develop synthetic methods for the construction of cyclic moieties such as those previously mentioned. The objectives that are addressed …

Nmr Spectroscopic Properties Of Nucleotides, And A New Method Of Numeric Calculation Of Raman Intensities For Organic Molecules, William R. Ehrhardt

Graduate Theses/Dissertations

General and accurate computational methodologies are currently lacking for large chemical systems. This is primarily due to the computational expense required to perform calculations on systems with one hundred or more atoms. Calculated spectroscopic properties could aid in the process of elucidating structural features of large biologically relevant molecules if accurate and inexpensive methods are developed. Towards this end the first steps were taken to design a general methodology for predicting NMR chemical shifts of large nucleic acid systems. It was found that HF and semi-empirical methods were not sufficient for optimization of nucleobases, and therefore larger nucleotide or nucleic …

Pnnl Dark Matter Bubble Chamber, Ryan Robinson

STAR Program Research Presentations

The Pacific Northwest National Laboratory (PNNL) prototype bubble chamber is intended to address issues encountered with the current PICO dark matter search detectors and improve the functionality of future experimental designs. The PNNL bubble chamber accomplishes this with a simplified interface between the hydraulic pressure controls and the target vessel and altering the standard chamber design such that it can be easily exchanged and replaced with vessels of various sizes and materials for testing purposes. The chamber itself is a glass vessel which houses perfluorobutane and holds the target fluid above room temperature and atmospheric pressure. The target fluid becomes …

Ultrafast And Nonlinear Spectroscopy Of Nanomaterials, Rami Anthony Khoury

LSU Doctoral Dissertations

Ultrafast and nonlinear spectroscopies are implemented in the investigation of excited-state dynamics and structural properties of materials and nanomaterials. In the first study, the excited-state dynamics of size-dependent colloidal TiO₂-Au nanocomposites are investigated using ultrafast transient absorption spectroscopy. The dynamics corresponding to the plasmon depletion band are characterized by electron-phonon and phonon-phonon coupling lifetimes that are observed to be independent of the gold nanocluster shell thickness. The excited-state dynamics corresponding to the interband transition of gold is also spectrally overlapped with the interfacial electron transfer lifetime, which is shown to decrease as the nanocluster shell thickness increases. In …

The Commutator Of The Runge Lenz Vector With Other Operators Of The H-Atoms Physics Using Maxima, Carl W. David

Chemistry Education Materials

Commutators of components of the Runge-Lenz vector and constants of the motion and ladder operators for the H-atom problem are evaluated using brute force calculus and Maxima.

Investigation Of Vaporization Enthalpies And Vapor Pressures Of Organic Compounds By Correlation Gas Chromatography, Carissa Nelson

Dissertations

Thermodynamic properties of organic compounds are useful to scientists and manufacturers in many areas of research and technology. This work focuses on measuring and reporting these properties on materials of commercial, environmental and scientific interest. Vaporization enthalpies and vapor pressures of several organic compounds have been studied using correlation gas chromatography (CGC) and are reported here as well as in recent publications. The CGC method allows for the indirect measurement of these properties in instances where these materials are available only in mixtures or in very small amounts.

The qualities of these measurements for any chosen target are directly related …

Cross Photoreaction Of Glyoxylic And Pyruvic Acids In Model Aqueous Aerosol, Sha-Sha Xia, Alexis J. Eugene, Marcelo I. Guzman

Chemistry Faculty Publications

Aerosols of variable composition, size, and shape are associated with public health concerns as well as with light-particle interactions that play a role in the energy balance of the atmosphere. Photochemical reactions of 2-oxocarboxylic acids in the aqueous phase are now known to contribute to the total secondary organic aerosol (SOA) budget. This work explores the cross reaction of glyoxylic acid (GA) and pyruvic acid (PA) in water, the two most abundant 2-oxocarboxylic acids in the atmosphere, under solar irradiation and dark thermal aging steps. During irradiation, PA and GA are excited and initiate proton-coupled electron transfer or hydrogen abstraction …

Development Of Chemistry Activities For Local Outreach In Stem, Emily Knight

Chemistry & Biochemistry Student Projects

Introduction: This research project was started because of an increase in outreach opportunities for the Department of Chemistry and Biochemistry. For similar opportunities, we now have bins of content that are simple to use, encouraging more students to participate in volunteer research.

Purpose: to find, modify, and/or create grade-level appropriate labs and demonstration activities for 5th-8th graders, with a specific focus on activities hat involve easily available components. These activities are intended to be used for outreach to local schools by chemistry student volunteers and released online to act as a resource for teachers.

Educational Resources: Polymers, Emily Knight

Chemistry & Biochemistry Student Projects

The document is meant to act as a resource for elementary through middle school teachers, featuring a science activity connected to Indiana state standards with grade-appropriate science connections aimed toward 5th, 6th, 7th, and 8th grade.

This document contains 3 polymer-based activities demonstrating different properties of polymers - the physical characteristics, possible absorbency, and elasticity. These activities can be abbreviated and used in rotating stations, planned over multiple days, or you can pick on that fits best with the classroom environment.

Educational Resources: Ionic Matching, Emily Knight

Chemistry & Biochemistry Student Projects

The document is meant to act as a resource for elementary through middle school teachers, featuring a science activity connected to Indiana state standards with grade-appropriate science connections aimed toward 5th, 6th, 7th, and 8th grade.

The entire point of this piece is simply to introduce balancing charges in ionic compounds. This is a simpler method to get students thinking about the idea, which also makes it suitable for pre-high school students. It gives a visual representation of how charges balance and cow cations pair with anions. At this level, it is very similar to least common denominator calculations.

Educational Resources: Homemade Fluorometer, Emily Knight

Chemistry & Biochemistry Student Projects

The document is meant to act as a resource for elementary through middle school teachers, featuring a science activity connected to Indiana state standards with grade-appropriate science connections aimed toward 5th, 6th, 7th, and 8th grade.