Nanoscience and Nanotechnology Commons^™

Preparation Of Nis2 Nanosheet And Its Application In Asymmetric Supercapacitor, Yuan-You Wang, Ya-Nan Liu, Dang-Qin Jin

Journal of Electrochemistry

In this work, the NiS₂ nanosheets have been synthesized using Ni(OH)₂ as a precursor through a sacrificial template method. The microstructure and chemical composition of as-prepared NiS₂ were characterized by XRD, EDS, BET, SEM and TEM techniques. The results showed that both Ni(OH)₂ and NiS₂ were composed of nanoplates. The electrochemical tests revealed that NiS₂ exhibited the high specific capacitance of 1067.3 F•g^-1 at a current density of 1 A•g^-1 and excellent rate performance. Furthermore, in order to evaluate the practical application of NiS₂, an asymmetric supercapacitor, NiS₂ as …

Core-Shell Pd@Pt Ultrathin Nanowires As Durable Oxygen Reduction Electrocatalysts, Xin Wang, Yun-Jie Xiong, Liang-Liang Zou, Qing-Hong Huang, Zhi-Qing Zou, Hui Yang

Journal of Electrochemistry

This paper describes a simple CO-assisted reduction approach for the controllable synthesis of ultrathin Pd nanowires along the one-dimensional (1D) direction. Ultrathin Pt films from one to several atomic layers were successfully decorated onto ultrathin Pd nanowires by utilizing Cu UPD deposition, and followed by in-situ redox replacement reaction of UPD Cu by Pt. The core–shell structure and composition of the Pd@Pt ultrathin nanowires have been verified using transmission electron microscopy and energy dispersive X-ray spectrometry. The core–shell Pd@Pt ultrathin nanowires exhibited comparative electrocatalytic activity and improved durability for the oxygen reduction reaction in comparison with commercial Pt black. The …

Three-Dimensional Nanomaterials For Supercapacitor Applications: From Metal Oxides To Metal Phosphides, Zhi Zheng

University of New Orleans Theses and Dissertations

Over the past few years, energy storage devices have received tremendous interest due to the increasing demand for sustainable and renewable energy in modern society. Supercapacitors are considered as one of the most promising energy storage devices because of their high power density and long cycle life. However, low energy density remains as the main shortcoming for supercapacitors. The overall performance of supercapacitors is predominantly determined by the characteristics of the electrodes. Specifically, constructing nanostructured electrode material has been proven as an efficient way to improve the performance by providing large surface area and short ionic and electronic diffusion paths. …

Fabrication And Modification Of Titania Nanotube Arrays For Harvesting Solar Energy And Drug Delivery Applications, Ahmed El Ruby Abdel Rahman Mohamed

Electronic Thesis and Dissertation Repository

The fast diminishing of fossil fuels in the near future, as well as the global warming caused by increasing greenhouse gases have motivated the urgent quest to develop advanced materials as cost-effective photoanodes for solar light harvesting and many other photocatalytic applications. Recently, titania nanotube arrays (TNTAs) fabricated by anodization process has attracted great interest due to their excellent properties such as: high surface area, vertically oriented, highly organized, one-dimensional, nanotubular structure, photoactivity, chemical stability and biocompatibility. This unique combination of excellent properties makes TNTAs an excellent photoanode for solar light harvesting. However, the relatively wide band gap energy of …

Synergistic Interactions Of H2 And N2 With Molten Gallium In The Presence Of Plasma, Maria L. Carreon, Daniel F. Jaramillo-Cabanzo, Indira Chaudhuri, Madhu Menon, Mahendra K. Sunkara

Physics and Astronomy Faculty Publications

The present study examines the interaction of hydrogen and nitrogen plasmas with gallium in an effort to gain insights into the mechanisms behind the synergetic effect of plasma and a catalytic metal. Absorption/desorption experiments were performed, accompanied by theoretical-computational calculations. Experiments were carried out in a plasma-enhanced, Ga-packed, batch reactor and entailed monitoring the change in pressure at different temperatures. The results indicated a rapid adsorption/dissolution of the gas into the molten metal when gallium was exposed to plasma, even at a low temperature of 100 °C. The experimental observations, when hydrogen was used, indicate that gallium acts as a …

Cellulose Nanofiber-Reinforced Impact Modified Polypropylene: Assessing Material Properties From Fused Layer Modeling And Injection Molding Processing, Jordan Elliott Sanders

Electronic Theses and Dissertations

The purpose of this research was to investigate the use of cellulose nanofibers (CNF) compounded into an impact modified polypropylene (IMPP) matrix. A IMPP was used because it shrinks less than a PP homopolymer during FLM processing. An assessment of material properties from fused layer modeling (FLM), an additive manufacturing (AM) method, and injection molding (IM) was conducted. Results showed that material property measurements in neat PP were statistically similar between IM and FLM for density, strain at yield and flexural stiffness. Additionally, PP plus the coupling agent maleic anhydride (MA) showed statistically similar results in comparison of IM and …

Transport Of Water And Ions Through Single-Walled Armchair Carbon Nanotubes: A Molecular Dynamics Study, Michelle Patricia Aranha

Doctoral Dissertations

The narrow hydrophobic interior of a carbon nanotube (CNT) poses a barrier to the transport of water and ions, and yet, unexpectedly, numerous experimental and simulation studies have confirmed fast water transport rates comparable to those seen in biological aquaporin channels. These outstanding features of high water permeability and high solute rejection of even dissolved ions that would typically require a lot of energy for separation in commercial processes makes carbon nanotubes an exciting candidate for desalination membranes. Extending ion exclusion beyond simple mechanical sieving by the inclusion of electrostatics via added functionality to the nanotube bears promise to not …

Structural And Elastic Properties Of Degenerate Sno Monolayers At Finite Temperature, Afsana Sharmin

Graduate Theses and Dissertations

Chalcogen-based layered superconductors with a litharge structure such as FeS and FeSe mono-layers undergo structural and superconducting phase transitions that are tunable by doping. Representing another material platform with a litharge structure but without valence d-electrons, SnO monolayers also display a structural ground state with a degenerate rectangular unit cell at zero temperature and a charge-tunable energy barrier that leads to a thermally-controllable structural phase change. Doped SnO monolayers with rectangular degenerate unit cells give rise to two-dimensional multiferroicity. Their two-dimensional elastic energy landscape adopts a basic analytic expression that is employed to discuss this structural transition. The results contained …

Generalized Ellipsometry On Complex Nanostructures And Low-Symmetry Materials, Alyssa Mock

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

In this thesis, complex anisotropic materials are investigated and characterized by generalized ellipsometry. In recent years, anisotropic materials have gained considerable interest for novel applications in electronic and optoelectronic devices, mostly due to unique properties that originate from reduced crystal symmetry. Examples include white solid-state lighting devices which have become ubiquitous just recently, and the emergence of high-power, high-voltage electronic transistors and switches in all-electric vehicles. The incorporation of single crystalline material with low crystal symmetry into novel device structures requires reconsideration of existing optical characterization approaches. Here, the generalized ellipsometry concept is extended to include applications for materials with …

Design And Simulation Of A Miniature Cylindrical Mirror Auger Electron Energy Analyzer With Secondary Electron Noise Suppression, Jay A. Bieber

USF Tampa Graduate Theses and Dissertations

In the nanoscale metrology industry, there is a need for low-cost instruments, which have the ability to probe the structrure and elemental composition of thin films. This dissertation, describes the research performed to design and simulate a miniature Cylindrical Mirror Analyzer, (CMA), and Auger Electron Spectrometer, (AES). The CMA includes an integrated coaxial thermionic electron source. Electron optics simulations were performed using the Finite Element Method, (FEM), software COMSOL. To address the large Secondary Electron, (SE), noise, inherent in AES spectra, this research also included experiments to create structures in materials, which were intended to suppress SE backgound noise in …

Investigating Scalable Manufacturing Of High-Conductivity Wires And Coatings From Ultra-Long Carbon Nanotubes, Pouria Khanbolouki

Mechanical Engineering ETDs

Carbon nanotubes (CNTs) are a promising candidate for next generation of electrical wirings and electromagnetic interference (EMI) shielding materials due to their exceptional mechanical and electrical properties. Wires and coatings from ultralong nanotubes that are highly crystalline, well-aligned and densely packed can achieve this goal. High-performance CNT conductors will be relatively lightweight and resistant to harsh conditions and therefore can potentially replace current conductors in many industries including aerospace, automotive, gas and oil.

This thesis investigates a new manufacturing approach, based on conventional solution coating and wire drawing methods, to fabricate high conductivity wires and coatings from ultra-long carbon nanotubes. …

Aliovalent Dopants In Zno Nanocrystals: Synthesis To Electronic Structure, Dongming Zhou

Doctoral Dissertations

Semiconductor nanocrystal doping has stimulated broad interest for many applications including solar energy conversion, nanospintronics, and phosphors or optical labels. The study of the chemistry and physics of doped colloidal semiconductor nanocrystals has been dominated in the literature by isovalent dopants such as Mn²⁺ and Co²⁺ ions in II-VI semiconductors, in which the dopant oxidation state is the same as the cation ions. Until recently, aliovalent dopants has received much attention due to the plasmonic properties. Aliovalent is when the oxidation states of the dopant in the lattice differs from the cation ions. In the plasmonic semiconductor nanocrystals, …

Nanowire-Based Light-Emitting Diodes: A New Path Towards High-Speed Visible Light Communication, Mohsen Nami

Physics & Astronomy ETDs

Nano-scale optoelectronic devices have gained significant attention in recent years. Among these devices are semiconductor nanowires, whose dimeters range from 100 to 200 nm. Semiconductor nanowires can be utilized in many different applications including light-emitting diodes and laser diodes. Higher surface to volume ratio makes nanowire-based structures potential candidates for the next generation of photodetectors, sensors, and solar cells. Core-shell light-emitting diodes based on selective-area growth of gallium nitride (GaN) nanowires provide a wide range of advantages. Among these advantages are access to non-polar m-plane sidewalls, higher active region area compared to conventional planar structures, and reduction of threading …

Effects Of Surface Modification Modes On Proton-Over-Vanadium Ion Selectivity Of Nafion®Membrane For Application In Vanadium Redox Flow Battery, Qing-Long Tan, Hai-Ning Wang, Shan-Fu Lu, Da-Wei Liang, Chun-Xiao Wu, Yan Xiang

Journal of Electrochemistry

The effect of surface modification modes on proton-over-vanadium ion selectivity was studied by spin-coating chitosan-Phosphotungstic Acid (PWA) as a single or double layer on Nafion membrane surface. To suppress the vanadium ions permeation through the Nafion? membrane in a vanadium redox flow battery (VRFB), the single surface-modified Nafion membrane (Nafion/chitosan-PWA)S and double surface-modified Nafion membrane (Nafion/chitosan-PWA)D demonstrated a 89.9% and 92.7% reduction of vanadium ion permeability in comparison with pristine Nafion, respectively. The (Nafion/chitosan-PWA)D exhibited betterhigher selectivity between proton and vanadium ions than the (Nafion/chitosan-PWA)S at the same layer thickness. Furthermore, the columbic efficiency for the VRFB single cell based …

Surface Chemical Properties Of Mo2C, W2C, Mo2N And W2N Probed With Co, Co2And O2 Adsorption: A Dft Analysis, Jingyun Ye, Tianyu Zhang, Lingyun Xu, Shuxia Yin, Krishanthi Weerasinghe, Pamela Ubaldo, Ping And Ge Qingfeng He

Journal of Electrochemistry

Transition metal carbides and nitrides are attractive materials for electrodes in many electrochemical energy storage and conversion applications. In the present study, we use density functional theory slab calculations to characterize the surface chemical properties of molybdenum (Mo) and tungsten (W) carbides and nitrides, namely, Mo₂C, W₂C, Mo₂N and W2N with the adsorption of CO, CO₂ and O₂. These probing molecules provide measures of in both acidity/basicity and redox property of for the surfaces of these carbides and nitrides. Our results show that Lewis basic sites were responsible for CO_{2 …}

Density Functional Investigation On Cathode/Electrolyte Interface In Solid-State Lithium Batteries, Xuelong Wang, Ruijuan Xiao, Yong Xiang, Hong Li, Liquan Chen

Journal of Electrochemistry

The rapidly expanding application of lithium ion batteries stimulates research interest on energy storage devices with higher energy density, better safety and faster charge/discharge speed. All-solid-state lithium batteries have been considered as promising candidates because of their fewer side reactions and better safety compared with conventional lithium-ion batteries with organic liquid electrolytes. Looking for well-matched electrode/electrolyte interfaces is one of the keys to ensuring good comprehensive performance of solid-state lithium batteries. In this report, with the aid of first-principles simulations, the local structure and lithium ions transportation properties of electrolyte surfaces and cathode/electrolyte interfaces are investigated. The β-Li₃PS …

A New Type Carbon Composited Molybdenum Doped Vanadium Oxide Nanowires As A Cathode Material For Sodium Ion Batteries, Guang-Rui Zhang, Li-Qiang Hu, Bao-Zhu Zhang

Journal of Electrochemistry

In recent years, the development of lithium ion batteries (LIBs) has been limited due to the insufficient lithium resource and increasing cost. As a promising candidate, sodium ion batteries (SIBs) with the similar electrochemical mechanism and lower cost than LIBs are developing rapidly. However, as a result of the larger radius of Na⁺ compared with Li⁺, the crystalline structures of the most electrode materials are damaged severely during the intercalation of Na⁺, which limits the electrochemical properties of SIBs. Thus, developing new types of electrode materials for SIBs is particularly important. Among the cathode materials, …

Cobalt-Doped Ceria/Reduced Graphene Oxide Nanocomposite As An Efficient Oxygen Reduction Reaction Catalyst And Supercapacitor Material, Shaikh Parwaiz, Kousik Bhunia, Ashok Kumar Das, Mohammad Mansoob Khan Dr, Debabrata Pradhan

Dr. Mohammad Mansoob Khan

Interplay Of Quantum Size Effect, Anisotropy And Surface Stress Shapes The Instability Of Thin Metal Films, Mikhail Khenner

Mathematics Faculty Publications

Morphological instability of a planar surface ([111], [011], or [001]) of an ultra-thin metal film is studied in a parameter space formed by three major effects (the quantum size effect, the surface energy anisotropy and the surface stress) that influence a film dewetting. The analysis is based on the extended Mullins equation, where the effects are cast as functions of the film thickness. The formulation of the quantum size effect (Z. Zhang et al., PRL 80, 5381 (1998)) includes the oscillation of the surface energy with thickness caused by electrons confinement. By systematically comparing the effects, their contributions into the …

Synthesis, Characterization, And Biological Activity Of Spherical Nucleic Acid (Sna) Constructs For Cancer Therapy And Imaging, Colin Calabrese

Arts & Sciences Electronic Theses and Dissertations

This dissertation focuses on the development of biocompatible oligonucleotide-based nanomaterials, known as spherical nucleic acids (SNAs), as therapeutic and diagnostic agents for intracellular gene regulation and in vivo cancer imaging by positron emission tomography (PET). SNAs consist of a nanoparticle core functionalized with a dense shell of oligonucleotides such as deoxyribonucleic acid (DNA). Detailed synthetic procedures and characterization of novel SNAs with purpose-built biocompatible core materials are described. The SNAs exhibit comparable chemical, physical and biological properties regardless of core composition. The functionalities of the SNAs were further tailored by deliberate design and chemical modification of their oligonucleotide sequences.

The …

Characterization Of Nanoparticles Using Solid State Nanopores, Santoshi Nandivada

Graduate Theses and Dissertations

Solid state nanopores are widely used in detection of highly charged biomolecules like DNA and proteins. In this study, we use a solid state nanopore based device to characterize spherical nanoparticles to estimate their size and electrical charge using the principle of resistive pulse technique. The principle of resistive pulse technique is the method of counting and sizing particles suspended in a fluid medium, which are electrophoretically driven through a channel and produce current blockage signals due to giving rise to a change in its initial current. This change in current is denoted as a current blockage or as a …

Ion Size Effects On The Properties Of Charge Regulating Electric Double Layers, Divya Jyoti Prakash

Nanoscience and Microsystems ETDs

The behavior of charged interfaces formed in various systems like colloidal solution, fuel cells, battery, electro-deposition, catalysis is governed by the properties of electrical double layer(EDL). Civilized model with charge regulation boundary condition determined by thermodynamic equilibrium at the interface has been used to model electrical double layer and shows that size of the solvent plays a critical role in characterizing the properties of EDL using classical density functional theory.This thesis investigates the impact of ion size in electrolyte solutions on the electrical double layer formed at the interface using a similar model. It is found that ion size greatly …

Elastic Properties Of Superconductors And Materials With Weakly Correlated Spins, Christian Binek

Christian Binek Publications

It is shown that in the ergodic regime, the temperature dependence of Young’s modulus is solely determined by the magnetic properties of a material. For the large class of materials with paramagnetic or diamagnetic response, simple functional forms of the temperature derivative of Young’s modulus are derived and compared with experimental data and empirical results. Superconducting materials in the Meissner phase are ideal diamagnets. As such, they display remarkable elastic properties. Constant diamagnetic susceptibility gives rise to a temperature independent elastic modulus for ceramic and single crystalline superconductors alike. The thermodynamic approach established in this report, paves the way to …

Characteristics And Mechanism For The Simons Electrochemical Fluorination Of Methanesulfonyl Fluoride, Wen-Lin Xu, Bao-Tong Li, Da-Wei Wang, Ya-Qiong Wang

Journal of Electrochemistry

The characteristics and mechanism for the Simons electrochemical fluorination processes were investigated during the electrochemical fluorination of CH₃SO₂F to CF₃SO₂F. The results showed that the reaction mechanism for the electrochemical fluorination of organic compounds to organic fluorides was the same as that of chemical fluorination processes using fluorinating agents such as CoF₃. The electrochemical fluorination in anhydrous HF was a heterogeneous process, and nickel fluorides on the surface of the nickel anode played the role of a mediator in the Simons process to transfer oxidation potential from the anode to …

Electrocatalysis Of Nanotin Dioxide In The Battery Reaction Of Zinc-Nitrobenzene, Xu-Guo Tu, Xiang-Yu Ma, Rui-Nan He, Xiao-Juan Wang, Chen Ling, Yun-Xia Sun, Song Chen

Journal of Electrochemistry

The tin dioxide (SnO₂) nanoparticles were synthesized by using a simple hydrothermal route in the presence of tetrapropyl ammonium bromide (TPAB) as a surfactant. Accordingly, the titanium mesh based SnO₂ catalyst electrode was prepared. The morphologies and structures of SnO₂ nanostructures were characterized by scanning electron microscopy and X-ray diffraction spectrometry. The influences of reactant concentration, reaction temperature and time on the morphology of the products were investigated in detail. The electrocatalytic performance of SnO₂ for the reduction of nitrobenzene with zinc was studied. Possible formation process and growth mechanism for such hierarchical SnO_{2 …}

Thin Film Thermal Deposition At Various Pressures, James Kela Yee Keen Grace

Senior Theses

This research was to verify the hypothesis that resistivity of metal's thin film deposited in a low-pressure environment is the same as its solid material. Thermal Evaporation is a thin film deposition technique in which metal inside a vacuum is evaporated, then deposited onto a surface. Higher quality metal films are deposited when the vacuum pressure is lower. At higher pressures, more air molecules are trapped within the layers of metal, thus increasing scattering sites and increasing the resistance. However, reaching a lower pressure requires more time and effort. In this research, films were deposited at various pressures and resistivities …

Find, Build, And Export Information For 3d Printing Of Your Favorite Molecules And Crystal Structures At Two Dedicated Websites, Paul R. Destefano, Peter Moeck

Student Research Symposium

As 3D printers require instructions, the Nano-Crystallography Group at Portland State University is creating two websites (http://nanocrystallography.org/3dconvert/ and http://nanocrystallography.research.pdx.edu/3d-print-files/convert/) where such instructions are created, interactively, for the atomic arrangements of virtually all known molecules and crystals.

We will prepare a "pipeline" into which crystallographic information enters from two curated open access crystallographic databases, is manipulated to create the desired 3D models, and then is exported in either STL format (the standard for monochrome 3D printing) or VRML/X3D (the ISO successor to STL). The two aforementioned databases are the North-American mirror of the Crystallography Open Database (http://nanocrystallography.org) …

Morphology Controlled Synthesis Of Copper Based Multimetallic Nanostructures And Their Electrocatalytic Properties For Methanol Oxidation Reaction, Leanne Elizabeth Mathurin

Graduate Theses and Dissertations

This research focuses on the development of shape-controlled synthesis of Cu NM, Cu-based bimetallic and trimetallic nanostructures, and their electrocatalytic properties for methanol oxidation reaction (MOR). Copper nanomaterials (Cu NM) with specific surface facets can tailor their catalytic activity. Understanding reagents responsible for Cu NM growth is important for morphology-controlled synthesis of the nanostructures. This research studies the halide influence on Cu NM growth and morphology in an oil-based synthesis. The morphology of the Cu NM varies with the halide type (i.e., Cl-, Br-, I-), and the halide concentration. Additionally, the type of Cu precursor also influenced the morphology of …

Exploring Thermoresponsive Affinity Agents To Enhance Microdialysis Sampling Efficiency Of Proteins, Thaddeus Vasicek

Graduate Theses and Dissertations

Affinity agents increase microdialysis protein relative recovery, yet they have not seen widespread use within the microdialysis community due to their additional instrumentation requirements and prohibitive cost. This dissertation describes new affinity agents for microdialysis that require no additional instrumentation to use, have nearly 100% particle recovery, are 7 times more cost efficient than alternatives, and have low specificity enabling their use for a wide variety of proteins. Initially gold nanoparticles were chosen as an affinity ligand support due to their high surface area/volume ratio and colloidal stability. Poly (N-isopropylacrylamide) was immobilized to the gold nanoparticles, which served to sterically …

Molecular Dynamics Simulations Of Dna-Functionalized Nanoparticle Building Blocks On Gpus, Tyler Landon Fochtman

Graduate Theses and Dissertations

This thesis discusses massively parallel molecular dynamics simulations of nBLOCKs using graphical processing units. nBLOCKs are nanoscale building blocks composed of gold nanoparticles functionalized with single-stranded DNA molecules. To explore greater simulation time scales we implement our nBLOCK computational model as an extension to the coarse grain molecular simulator oxDNA. oxDNA is parameterized to match the thermodynamics of DNA strand hybridization as well as the mechanics of single stranded DNA and double stranded DNA. In addition to an in-depth review of our implementation details we also provide results of the model validation and performance tests. These validation and performance tests …