Determining Material Structures And Surface Chemistry By Genetic Algorithms And Quantum Chemical Simulations,
2021
University of Kentucky
Determining Material Structures And Surface Chemistry By Genetic Algorithms And Quantum Chemical Simulations, Josiah Jesse Roberts
Theses and Dissertations--Chemistry
With the advent of modern computing, the use of simulation in chemistry has become just as important as experiment. Simulations were originally only applicable to small molecules, but modern techniques, such as density functional theory (DFT) allow extension to materials science. While there are many valuable techniques for synthesis and characterization in chemistry laboratories, there are far more materials possible than can be synthesized, each with an entire host of surfaces. This wealth of chemical space to explore begs the use of computational chemistry to mimic synthesis and experimental characterization. In this work, genetic algorithms (GA), for the former, and …
Plasmon Enhanced Single Molecule Fluorescence In Zero Mode Waveguides (Zmws),
2021
University of Kentucky
Plasmon Enhanced Single Molecule Fluorescence In Zero Mode Waveguides (Zmws), Abdullah Masud
Theses and Dissertations--Chemistry
Plasmonic nanostructures are an extensive research focus due to their ability to modify the photophysical properties of nearby fluorophores. Surface plasmons (SP), defined as the collective oscillation of delocalized electrons, are the fundamental characteristic primarily responsible for altering those photophysical properties. Studying fluorophores at the single-molecule level has received significant attention since more specific information can be extracted from single molecule-based studies, which otherwise could be obscured in ensemble studies. However, single-molecule studies are inherently challenging because the signal from a single molecule is usually dim, making it difficult to detect. The situation is even worse in a crowded environment …
Identification Of New Pathways For Co Oxidation On Rh(111) & Spatial And Structural Control Of O-Induced Reconstruction Of Ag(111),
2021
Loyola University Chicago
Identification Of New Pathways For Co Oxidation On Rh(111) & Spatial And Structural Control Of O-Induced Reconstruction Of Ag(111), Marie Turano
Dissertations
Understanding the fundamentals of oxygen surface structures under a variety of conditions is pivotal to determining reactivity of heterogeneous catalysis. Exposure of catalytically active metal surfaces to high oxygen coverages results in a myriad of surface structures. A further complication is the formation of subsurface oxygen (Osub) or oxygen present in the near subsurface region of the metal. It is known to form in transition metals yet the absorption of oxygen and resultant formation of Osub is not equivalent across all catalytically relevant metals. As a result, it is difficult to predict the stability and efficacy of the formation of …
Proto-Rna Synthesis Using Glycerol And Phosphate Anion,
2021
The University of Akron
Proto-Rna Synthesis Using Glycerol And Phosphate Anion, Noah Parker
Williams Honors College, Honors Research Projects
Nucleic acids are important molecules for all life, serving as the primary molecules for information storage and reproduction. RNA has long been thought to be the molecule that initiated protein synthesis. However, RNA has recently been thought to be too complex to synthesize prebiotically. Through a 1:1 mole ratio condensation of glycerol and phosphoric acid, I generated glycerol-phosphate oligomers that resemble a primitive form of the carbon-phosphate backbone of RNA. 75 mmol MgCl2 was added to some samples to see if the Mg cation could stabilize the reaction intermediates and further promote longer proto-RNA oligomers. These samples were all heated …
Predicting Material Properties: Applications Of Multi-Scale Multiphysics Numerical Modeling To Transport Problems In Biochemical Systems And Chemical Process Engineering,
2021
University of Kentucky
Predicting Material Properties: Applications Of Multi-Scale Multiphysics Numerical Modeling To Transport Problems In Biochemical Systems And Chemical Process Engineering, Tom Pace
Theses and Dissertations--Physics and Astronomy
Material properties are used in a wide variety of theoretical models of material behavior. Descriptive properties quantify the nature, structure, or composition of the material. Behavioral properties quantify the response of the material to an imposed condition. The central question of this work concerns the prediction of behavioral properties from previously determined descriptive properties through hierarchical multi-scale, multiphysics models implemented as numerical simulations. Applications covered focus on mass transport models, including sequential enzyme-catalyzed reactions in systems biology, and an industrial chemical process in a common reaction medium.
Porous Polymer Compositions For The Synthesis Of Monolithic Bimodal Microporous/Macroporous Carbon Compositions Useful For Selective Co2 Sequestration,
2021
Missouri University of Science and Technology
Porous Polymer Compositions For The Synthesis Of Monolithic Bimodal Microporous/Macroporous Carbon Compositions Useful For Selective Co2 Sequestration, Nicholas Leventis, Chariklia Sotiriou-Leventis, Malik Adnan Saeed
Patents
The present invention discloses novel porous polymeric compositions comprising random copolymers of amides, imides, ureas, and carbamic-anhydrides, useful for the synthesis of monolithic bimodal microporous/macroporous carbon aerogels. It also discloses methods for producing said microporous/macroporous carbon aerogels by the reaction of a polyisocyanate compound and a polycarboxylic acid compound, followed by pyrolytic carbonization, and by reactive etching with CO2 at elevated temperatures. Also disclosed are methods for using the microporous/macroporous carbon aerogels in the selective capture and sequestration of carbon dioxide.
Highly Porous Ceramic And Metal Aerogels From Xerogel Powder Precursors, And Methods For Thier Production And Use,
2021
Missouri University of Science and Technology
Highly Porous Ceramic And Metal Aerogels From Xerogel Powder Precursors, And Methods For Thier Production And Use, Nicholas Leventis, Chariklia Sotiriou-Leventis, Malik Adnan Saeed, Parwani Rewatkar, Tahereh Taghvaee
Patents
The present invention discloses novel methods for producing highly porous ceramic and/or metal aerogel monolithic objects that are hard, sturdy, and resistant to high temperatures. These methods comprise preparing nanoparticulate oxides of metals and/or metalloids via a step of vigorous stirring to prevent gelation, preparing polymer-modified xerogel powder compositions by reacting said nanoparticulate oxides with one or more polyfunctional monomers, compressing said polymer-modified xerogel powder compositions into shaped compacts, and carbothermal conversion of the shaped xerogel compacts via pyrolysis to provide the highly porous ceramic and/or metal aerogel monolithic objects that have the same shapes as their corresponding xerogel compact …
Multiple Wetting−Dewetting States Of A Water Droplet On Dual-Scale Hierarchical Structured Surfaces,
2021
University of Nebraska - Lincoln
Multiple Wetting−Dewetting States Of A Water Droplet On Dual-Scale Hierarchical Structured Surfaces, Yurui Gao, Yuan Liu, Jian Jiang, Chongqin Zhu, Craig Zuhlke, Dennis Alexander, Joseph S. Francisco, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
Surfaces with microscale roughness can entail dualscale hierarchical structures such as the recently reported nano/ microstructured surfaces produced in the laboratory (Wang et al. Nature 2020, 582, 55−57). However, how the dual-scale hierarchical structured surface affects the apparent wetting/ dewetting states of a water droplet, and the transitions between the states are still largely unexplored. Here, we report a systematic large-scale molecular dynamics (MD) simulation study on the wetting/dewetting states of water droplets on various dual-scale nano/near-submicrometer structured surfaces. To this end, we devise slab-water/slab-substrate model systems with a variety of dual-scale surface structures and with different degrees of intrinsic …
Cobalt, Molybdenum, And Nickel Complexes, Natural Zeolites, Epoxidation, And Free Radical Reactions,
2021
Michigan Technological University
Cobalt, Molybdenum, And Nickel Complexes, Natural Zeolites, Epoxidation, And Free Radical Reactions, Nicholas K. Newberry
Dissertations, Master's Theses and Master's Reports
Chapter 2 is based on the synthesis and study of the compounds of the bidentate ligand ((5-phenyl-1H-pyrazol-3-yl)methyl)phosphine oxide with molybdenum and cobalt as the transition metal. The complexes were analyzed via FTIR, NMR, UV-Vis, Fluorescence Spectroscopy, TGA, DFT, and XRD. Chapter 3 resulted in the synthesis of the complexes [Ni(II)SSRRL](PF6)2 and [Ni(II)SRSRL](Cl)(PF6) of which [Ni(II)SRSRL](Cl)(PF6) had not been previously analyzed. Both products were analyzed via FTIR, NMR, UV-Vis, CV, DFT, and XRD. Chapter 5 contains the results of the characterization and modification of 4 natural zeolites (AZLB-Na, AZLB-Ca, NM-CA, NV-Na) from the United States in an attempt to increase the …
Relating Detonation Parameters To The Detonation Synthesis Of Nanomaterials,
2021
Missouri University of Science and Technology
Relating Detonation Parameters To The Detonation Synthesis Of Nanomaterials, Martin Langenderfer
Doctoral Dissertations
“This research investigates the physical and chemical processes that contribute to the detonation synthesis of silicon carbide nanoparticles. Bulk production of SiC nanoparticles through detonation is possible due to pressures achieved over 20 GPa and temperatures over 2000 K as well as quenching rates in excess of 13 billion K/second. These conditions catalyze reaction and bottom-up molecular growth while retaining particles < 100 nm in diameter. In this work, detonation synthesis of SiC was demonstrated by incorporation of polycarbosilane, an SiC precursor material, into an RDX/TNT explosive matrix prior to detonation. Detonation Synthesis of SiC was also accomplished by reacting elemental silicon with carbon liberated by the detonation of negatively oxygen balanced TNT. Hydrodynamic simulation of a 60:40 mass ratio RDX/TNT detonation created conditions thermodynamically suitable to produce cubic silicon carbide within the first 500 nanoseconds after the passage of the detonation wave while carbon remains chemically reactive for molecular formation. Simulations and experimental tests indicated that loading configuration and impedance mismatch of the precursor additives used in detonation synthesis results in conditions in the additives that exceed the accepted detonation pressure of the explosive by greater than three times. Finally, a full factorial experimental design showed increasing silicon concentration, reducing silicon size, and reducing oxygen balance by adjusting the ratio of RDX to TNT decreased the explosives detonation pressure by 20% and increased the soot yield and concentration of SiC observed in the detonation products by 82% and 442% respectively”--Abstract, page iv.
Development Of Poly (Methyl Methacrylate-Co-Methacrylic Acid) Based Electrolytes With Synthesized And Commercial Ionic Liquids For Dye Sensitized Solar Cells,
2021
Universiti Malaya
Development Of Poly (Methyl Methacrylate-Co-Methacrylic Acid) Based Electrolytes With Synthesized And Commercial Ionic Liquids For Dye Sensitized Solar Cells, Vhaissnavin Sundararajan
Student Works (2020-2029)
A persistent challenge for expanding global population and soaring economic progress has always been ensuring everyone has enough access to energy supply. At present, the high dependency on fossil fuel derived energy has led to a crisis that necessitated a shift of attention towards greener energy sources like solar. Solar energy serves as the most consistent back up energy and the best option for environmental conservation. Among the listed solar harvesters, dye sensitized solar cells (DSSCs) bring about vast potential in efficient conversion of solar to electrical energy. The fact that this discovery has not reached its pinnacle and every …
Novel Electrochemical Sensor Based On Integration Of Nanoporous Gold With Molecularly Imprinted Polymer For Detection Of Arsenic Ion(Iii),
2020
1. Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Production and Construction Corps/School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832000, China;3. Xinjiang Xiangsheng New Material Technology Co., Ltd. Hami Xinjiang 839000, China;
Novel Electrochemical Sensor Based On Integration Of Nanoporous Gold With Molecularly Imprinted Polymer For Detection Of Arsenic Ion(Iii), Wu-Wei Ma, Qi-Gang Chang, Xiong-Fang Shi, Yan-Bin Tong, Li Zhou, Bang-Ce Ye, Jian-Jiang Lu, Jin-Hu Zhao
Journal of Electrochemistry
Arsenic, a toxic chemical element, is detrimental to environment and human health in particular. Therefore, the development of simple, fast, and accurate arsenic ion (As3+) detection methods has attracted extensive attention. In this work, an electrochemical sensor based on molecular imprinted polymer (MIP) and nano-porous gold (NPG) modified indium tin oxide (ITO) electrode (MIP/NPG/ITO) was developed for determination of As3+ in water with different quality. NPG with high conductivity, large specific surface area and high biocompatibility was prepared in situ on ITO surface by a green electrodeposition method using simple and controllable steps. Then, a layer of …
Effect Of 18-Crown-6 Additive On Chromium Electrodeposition In Ionic Liquid,
2020
State Key Laboratory of Chemical Engineering, East China University of Science and Technology,Shanghai 200030, China;
Effect Of 18-Crown-6 Additive On Chromium Electrodeposition In Ionic Liquid, Yi-Jie Wang, Dong-Fang Niu, Xin-Sheng Zhang
Journal of Electrochemistry
Trivalent chromium ion (Cr3+) is used for electrodeposition due to its low toxicity. Electrodeposition in ionic liquids can greatly solve for hydrogen evolution problem. However,as a widely used Cr(III) precursor, chromium chloride hydrate (CrCl3·6H2O), still contains water. In the presence of water, Cr3+ will form a complex coordination structure with water molecules ([Cr(H2O)6]3+), which is a stable octahedral structure and is difficult to be directly reduced to chromium metal. Therefore, coordination agents should be added into the bath. In this work, the effect of 18-Crown-6 additive on …
Effect Of Reaction Conditions On Cu⁃Catalyzed Co2 Electroreduction,
2020
1. CAS Key Laboratory of Low-carbon Conversion Science and Engineering, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210, China;2. University of Chinese Academy of Sciences, Beijing, 100049, China;
Effect Of Reaction Conditions On Cu⁃Catalyzed Co2 Electroreduction, Chang Zhu, Wei Chen, Yan-Fang Song, Xiao Dong, Gui-Hua Li, Wei Wei, Yu-Han Sun
Journal of Electrochemistry
Electrochemical conversion of carbon dioxide (CO2) driven by renewable electricity that can meet both carbon emission reduction and renewable energy utilization has been rapidly developed in recent years. Copper (Cu) catalyst has long been a promising candidate for CO2 electroreduction applications because of its natural abundance and specific capability of producing a substantial amount of C2 products. However, various metallic Cu electrodes reported have been significantly influenced by the adsorption of certain cation/anion ions, resulting in wide-span catalytic activities and selectivity for various products. In addition, a recent report demonstrated that by virtue of gas-diffusion flow cell …
Numerical Simulations Of Current And Temperature Distribution Of Symmetrical Double-Cathode Solid Oxide Fuel Cell Stacks Based On The Theory Of Electric-Chemical-Thermal Coupling,
2020
1. Faculty of Civil Engineering and Mechanics, Jiangsu University, Zhenjiang 212013, China;2. Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China;
Numerical Simulations Of Current And Temperature Distribution Of Symmetrical Double-Cathode Solid Oxide Fuel Cell Stacks Based On The Theory Of Electric-Chemical-Thermal Coupling, Cheng-Rong Yu, Jian-Guo Zhu, Cong-Ying Jiang, Yu-Chen Gu, Ye-Xin Zhou, Zhuo-Bin Li, Rong-Min Wu, Zheng Zhong, Wan-Bing Guan
Journal of Electrochemistry
Solid oxide fuel cell (SOFC) is a high-efficient clean conversion device for future energy management. Because of the low antioxidant reduction ability and complex thermal stress, the structure of traditional asymmetrical thin anode-supported planar SOFC is easily to be broken under stack operating conditions. To overcome these defects, a new complete symmetrical SOFC based on double-sided cathodes was developed. To study the influences of gas flow direction and current collection mode on the cell performance inside stack, a numerical model was established by finite element method based on the theory of electro-thermo-chemo multiphysical coupling. By applying this model, the molar …
Pitting Behaviors Of Passivated And Trans-Passivated 304 Stainless Steel,
2020
1. Center for Marine Materials Corrosion and Protection, College of Materials, Xiamen University, Xiamen 361005, Fujian, China;
Pitting Behaviors Of Passivated And Trans-Passivated 304 Stainless Steel, Jing Shen, Zi-Ming Wang, Da-Jiang Zheng, Guang-Ling Song
Journal of Electrochemistry
In order to further understand the passivation and trans-passivation behaviors of 304 stainless steels, the samples were pretreated under different polarization potentials and their corrosion behaviors were investigated. It was found that the pitting potential of the untreated sample was the same as that of the sample treated with 1.1 V trans-passivation potential, while the pitting potential of the sample treated with 0.5 V passivation treatment was the highest. This observation was further verified by the SKP results. According to SEM observations, the surface of the untreated sample preserved a polishing morphology, while the surface of the 0.5 V passivation …
Degradation And Thermal Characteristics Of Lini0.8Co0.15Al0.05O2/Graphite Lithium Ion Battery After Different State Of Charge Ranges Cycling,
2020
1. Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, CAS Key Laboratory of Renewable Energy, Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China;
Degradation And Thermal Characteristics Of Lini0.8Co0.15Al0.05O2/Graphite Lithium Ion Battery After Different State Of Charge Ranges Cycling, Cun Wang, Wei-Jiang Zhang, Teng-Fei He, Bo Lei, You-Jie Shi, Yao-Dong Zheng, Wei-Lin Luo, Fang-Ming Jiang
Journal of Electrochemistry
The LiNi0.8Co0.15Al0.05O2 (NCA) cathode exhibits high energy density and large reversible capacity, which plays an essential role in the field of electric vehicles (EVs). However, low capacity retention and poor thermal stability limit its application. Few literatures are found for the capacity degradation mechanism of NCA/graphite batteries at home and abroad. The different state of charge (SOC) ranges cycle degradation behaviors of 18650-type NCA/graphite (2.4 Ah) battery were studied in this paper. The SOC ranges considered were 0% ~ 20% (low), 20% ~ 70% (medium), 70% ~ 100% (high), and 0% ~ 100% …
Preparations And Sodium Storage Properties Of Ni3S2@Cnt Composite,
2020
School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050;
Preparations And Sodium Storage Properties Of Ni3S2@Cnt Composite, Ming-Tao Duan, Yan-Shuang Meng, Hong-Shuai Zhang
Journal of Electrochemistry
Transition metal sulfides (TMSs)-based electrode materials with highly reversible sodium storage have attracted extensive attentions as one of the most prospective electrode materials for sodium ion batteries (SIBs). However, low cycling stability and rate property caused by large volume expansion and poor electronic conductivity during the electrochemical reaction still hamper their further practical application. In this work, in-situ encapsulated Ni3S2 nanoparticles in carbon nanotubes (Ni3S2@CNT) have been successfully fabricated as an anode material for high-performance SIBs by a one-step solid-phase calcination process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), …
Effect Of Stereotaxically-Constructed Graphene On The Negative Electrode Performance Of Lead-Acid Batteries,
2020
Collaborative Innovation Center of Sustainable Energy Materials, Guangxi University,Nanning 530004, Guangxi, China;
Effect Of Stereotaxically-Constructed Graphene On The Negative Electrode Performance Of Lead-Acid Batteries, Pin-Song Chen, Yi-Tao Hu, Xin-Yi Zhang, Pei-Kang Shen
Journal of Electrochemistry
With the advantages of high ratio surface area, excellent conductivity and high stability, the stereotaxically-constructed graphene (SCG) material was added to the negative active material (NAM) of lead-acid battery for improving battery performance. XRD, SEM and cyclic voltammetry tests were carried out to analyze the influence of SCG on negative active material. It is found that the conversion efficiency of lead sulfate to lead in the negative active material added with SCG material was higher than that of control group, and the particle size of the lead sulfate obtained after the discharge reaction was smaller, which are favorable factors for …
Core-Shell Structured Ru@Ptru Nanoflower Electrocatalysts Toward Alkaline Hydrogen Evolution Reaction,
2020
State Key Laboratory of Fine Chemicals, School of Chemical Engineering,Dalian University of Technology, Dalian 116024, Liaoning, China;
Core-Shell Structured Ru@Ptru Nanoflower Electrocatalysts Toward Alkaline Hydrogen Evolution Reaction, Xue-Liang Wang, Yuan-Yuan Cong, Chen-Xi Qiu, Sheng-Jie Wang, Jia-Qi Qin, Yu-Jiang Song
Journal of Electrochemistry
Water electrolysis for hydrogen production is beneficial for solving the problem of energy crisis and environmental issues. It is necessary to study highly active and cost-effective catalysts toward hydrogen evolution reaction (HER) to reduce the consumption of noble metals. Herein, we report the synthesis of core-shell structured Ru@Pt0.24Ru nanoflowers electrocatalyst by stepwise reduction of Ru and Pt precursors in the mixture of oleylamine and benzyl alcohol at 160 oC. The average diameter of the resultant Ru@Pt0.24Ru was 16.5±4.0 nm with a bulk atomic ratio between Pt and Ru of 0.24:1 and a surface ratio of …
