Materials Chemistry Commons^™

Passivation Behavior Of Aluminum Alloy During Electrochemical Machining And Its Effects On The Machining Performance, Li-Min Jiang, Wen-Bo Deng, Jun-Long Ying

Journal of Electrochemistry

The passivation behavior of aluminum alloy during electrochemical machining was investigated and discussed. The effects of processing voltage, current density, space of electrodes and electrolyte composition on electrochemical machining performance were explored. The results indicate that the electrochemical machining aluminum alloy in the composite electrolyte system containing NaNO₃ and NaF existed passivation phenomenon. Passivation action decreaseed the current efficiency and made it varied greatly with the current density. Also the passivation shifted the interspace characteristic curve of electrode notably to a negative direction. There was not passivation phenomenon in the composite electrolyte system containing the same concentrations of NaCl …

Fabrication And Impedance Performance Of Gradient Lani0.6Fe0.4O3-δ-Gd0.2Ce0.8O2 Composite Cathodes For Intermediate Temperature Solid Oxide Fuel Cell, Yang Li, Bo Huang, Meng Yuan, Zhi-Qiu Zhang, Zong-Yao Liu, Xu-Chen Tang, Xin-Jian Zhu

Journal of Electrochemistry

A LNF-GDC composite cathode with a gradual change in the composition between ScSZ electrolyte and LNF cathode was fabricated to reduce the cathode polarization resistance (R_p). The gradual change in composition between ScSZ electrolyte and LNF cathode shows the decreases in the charge transfer resistance (R_ct) and gas phase diffusion resistance (R_d). The results revealed that the Rp value, measuring 0.452 Ω·cm² at 750 °C, was the lowest for LNF-GDC composite cathodes with three layers and gradient changes in composition between ScSZ and LNF (Cathode C),, whereas the Rp value of 70%LNF-30%GDC composite …

Surface Structure And Electrochemical Performance Of Zno Coated Lini1/3Co1/3Mn1/3O2, Chang-Wei Liu, Yu Wang, Yu-Zhong Guo, Lu-Lu Dan, Jian-Hua Wang

Journal of Electrochemistry

The surface of LiNi_1/3Co_1/3Mn_1/3O₂ particles were modified by ZnO. Surface structure and electrochemical properties of the coated materials were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical tests. The results show that a ZnO coating affects the surface composition of LiNi_1/3Co_1/3Mn_1/3O₂ particles. The surface contents of nickel and manganese increase with the amount of ZnO coating. ZnO can react with LiNi_1/3Co_1/3Mn_1/3O₂ and a complex oxide is formed during the heat-treatment at above 400 ^oC. The …

Preparation Of Pd/Tio2/C Catalyst And Its Electrocatalytic Performance In Basic Solution For Ethanol Oxidation, Qiao-Xia Li, Yi-Chao Yang, Ming-Shuang Liu, Hong-Min Mao, Qun-Jie Xu

Journal of Electrochemistry

Nanoparticles TiO₂ were prepared by hydrothermal method using precursor tetrabutyl titanate. The Pd/TiO₂/C catalyst was synthesized by liquid phase reducing method supported on nano TiO₂ and Vulcan carbon XC-72. The Pd/TiO₂/C catalyst was characterized by XRD, TEM, cyclic voltammetry, and chronopotentiometry. XRD confirmed the face-centered cubic structure of Pd particles, and TEM indicated that Pd particles (size 3 ~ 4 nm) dispersed uniformly on TiO₂ and carbon XC-72. The results from cyclic voltammogram and chronopotentiogram showed the higher ethanol oxidation activity and stability of Pd/TiO₂/C catalyst (20% Pd) as compared with …

Design And Development Of A Novel Glucose Biosensor Based On The Ferrocene-Functionalized Fe3O4 Nanoparticles/Carbon Nanotubes/Chitosan Nanocomposite Film Modified Electrode, Hua-Ping Peng, Dai-Jun Zha, Wei Chen, Ai-Lin Liu, Xin-Hua Lin

Journal of Electrochemistry

A novel platform for the fabrication of glucose biosensor was successfully constructed by entrapping glucose oxidase (GOD) in a ferrocene monocarboxylic acid-aminated Fe₃O₄ magnetic nanoparticles conjugate (FMC-AFNPs)/chitosan (CS)/multiwall carbon nanotubes (MWNTs) nanocomposite. The formation of FMC-AFNPs could effectively prevent the leakage of ferrocene and retain its electrochemical activity. This GOD/FMC-AFNPs/CS/MWNTs matrix provided a biocompatible microenvironment for retaining the native activity of the immobilized GOD. Moreover, the presence of MWNTs enhanced the charge-transport properties of the composite and facilitated electron transfer between the GOD and the electrode for the electrocatalysis of glucose. Under the optimal conditions the designed …

A New Nonenzymatic Glucose Sensor Based On The Cuo Nanoplatelets, Yan-Cai Li, Fu-Ying Huang, Shun-Xing Li, Jie Chen, Shu-Qing Feng, Fei Wang

Journal of Electrochemistry

The CuO nanoplatelets were synthesized by hydrothermal method. The structure and morphology of the CuO nanoplatelets were characterized by TEM and XRD. A new nonenzymatic glucose sensor was constructed by immobilizing the CuO nanoplatelets on glassy carbon electrode with Nafion. The electrochemical performance of the CuO/Nafion/GCE for the detection of glucose was investigated by cyclic voltammetry and current-time curve. The experiment results showed that the linear dependence of the sensor was 0.01 to 0.3 mmol·L^-1 for glucose with a sensitivity of 1783.58 μA·mmol^-1·L·cm^-2, and the detection limit of the sensor was 0.80 μmol·L^-1 (S/N …

Responsive Polymers For Biosensing And Protein Delivery, Molla R. Islam, Yongfeng Gao, Xue Li, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

In this feature article, we review some of the most recent advances in the field of materials chemistry for biosensing, disease diagnostics, and drug delivery. Our recent work on the development of responsive polymer-based platforms for biosensing and drug delivery will also be highlighted. This feature article is meant to outline the breadth of the utility of polymer-based materials for select applications, as well as their enormous potential impact on future technologies.

Large-Scale Solution Synthesis Of Narrow Graphene Nanoribbons, Timothy H. Vo, Mikhail Shekhirev, Donna A. Kunkel, Martha D. Morton, Eric Berglund, Lingmei Kong, Peter M. Wilson, Peter A. Dowben, Axel Enders, Alexander Sinitskii

Nebraska Center for Materials and Nanoscience: Faculty Publications

According to theoretical studies, narrow graphene nanoribbons with atomically precise armchair edges and widths of(1.1 eV), which makes them potentially promising for logic applications. Different top–down fabrication approaches typically yield ribbons with width >10nm and have limited control over their edge structure. Here we demonstrate a novel bottom–up approach that yields gram quantities of high-aspect-ratio graphene nanoribbons, which are only ~1 nm wide and have atomically smooth armchair edges. These ribbons are shown to have a large electronic bandgap of ~1.3 eV, which is significantly higher than any value reported so far in experimental studies of graphene nanoribbons prepared by …

Fabrication Of Cds Nanoparticle Coated Jasmonate Conjugates And Their Interactions With Mammalian Cells, Nazmul Sarker Fcrh '13, Stacey Barnaby Fcrh '11, Ipsita Bannerjee

The Fordham Undergraduate Research Journal

In this work, we have grown CdS nanoparticles on jasmonate nanoassemblies biomimetically and examined their interactions with mammalian cells. In general, plants naturally secrete the phytohormone jasmonic acid during development and in response to biotic and abiotic stress as a defense mechanism (Traw and Bergelson 2003; Sembdner and Parthier 1993). We have developed a new class of nanomaterials by utilizing nanoassemblies of the plant phytohormone jasmonic acid (JA) as templates for the growth of quantum dots, which may have potential applications as sensors and may potentially be utilized for bioimaging applications.

Water Capacity Of Tuffoam, Kristina Fuller

STAR Program Research Presentations

TufFoam is a Sandia-developed, closed cell polyurethane foam designed for insulation and impact force dispersion. Unlike similar commercially available foams, TufFoam does not require the carcinogenic compound toluene diisocyanate in the production process. Since properties of foams can change with moisture content, this study examines the capacity of TufFoam to absorb water. Samples of TufFoam were created in two different thicknesses, at three different densities, and with two different exteriors and were weighed to the microgram. Weights were tracked from ambient conditions until the disks had finished drying in ovens and then while being moistened in airtight canisters held at …

Degradation Of High Voltage Glass Fiber-Reinforced Polymer Matrix Composites By Aggressive Environmental Conditions, Tianyi Lu

Electronic Theses and Dissertations

Polymer matrix composites reinforced with either E glass or ECR glass fibers-reinforced are used in a variety of high voltage electrical applications because of their advantages like lower weight and cost. However, they can be damaged by aggressive in-service conditions such as high temperature, ultraviolet radiation, moisture, ozone and corrosive environments. Different degradation mechanisms can develop in high voltage PMCs under those extreme environments, which, in turn, can affect the long term structural durability of the composites. A set of PMCs reinforced with ECR-glass and E-glass fibers embedded in four different resins has been investigated in this study. In addition, …

Spontaneous Formation Of One-Dimensional Hydrogen Gas Hydrate In Carbon Nanotubes, Wenhui Zhao, Lu Wang, Jaeil Bai, Joseph S. Francisco, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We present molecular dynamics simulation evidence of spontaneous formation of quasi-one-dimensional (Q1D) hydrogen gas hydrates within single-walled carbon nanotubes (SW-CNTs) of nanometer-sized diameter (1−1.3 nm) near ambient temperature. Contrary to conventional 3D gas hydrates in which the guest molecules are typically contained in individual and isolated cages in the host lattice, the guest H₂ molecules in the Q1D gas hydrates are contained within a 1D nanochannel in which the H₂ molecules form a molecule wire. In particular, we show that in the (15,0) zigzag SW-CNT, the hexagonal H₂ hydrate tends to form, with one H₂ molecule …

A Photoelectron Spectroscopy And Ab Initio Study Of The Structures And Chemical Bonding Of The B25 − Cluster, Zachary A Piazza, Ivan H. Popov, Wei-Li Li, Rhitankar Pal, Xiao Cheng Zeng, Alexander I. Boldyrev, Lai-Sheng Wang

Xiao Cheng Zeng Publications

Photoelectron spectroscopy and ab initio calculations are used to investigate the structures and chemical bonding of the B₂₅ − cluster. Global minimum searches reveal a dense potential energy landscape with 13 quasi-planar structures within 10 kcal/mol at the CCSD(T)/6-311+G(d) level of theory. Three quasi-planar isomers (I, II, and III) are lowest in energy and nearly degenerate at the CCSD(T) level of theory, with II and III being 0.8 and 0.9 kcal/mol higher, respectively, whereas at two density functional levels of theory isomer III is the lowest in energy (8.4 kcal/mol more stable than I at PBE0/6-311+G(2df) level). Comparison with …

Synthesis And Characterization Of Sugar Based Low Molecular Weight Gelators And The Preparation Of Chiral Sulfinamides, Hari Prasad Reddy Mangunuru

Chemistry & Biochemistry Theses & Dissertations

Low molecular weight gelators (LMWGs) have received considerable attention in the field of chemistry from last few decades. These compounds form self-assembled fibrous networks like micelles, cylindrical, sheets, fibers, layers and so on. The fibrous network entraps the solvent and forms gel, because of the self-assembly phenomenon and their demonstrated potential uses in a variety of areas, ranging from environmental to medicinal applications.

Sugars are good starting materials to synthesize the new class of LMWG's, because these are different from some expensive materials, these are natural products. We have synthesized and characterized the LMGS's based on D-glucose and D …

Polyaniline In Situ Grafted To Graphene Sheets, Erwin P. Enriquez, Elliard Roswell S. Yanza, Geoffrey Matthew C. Tan, Christine Joy Querebilo, Armando Somintac, Arnel Salvador

Chemistry Faculty Publications

Graphene is one of the most promising allotropes of carbon with wide applications in nanotechnology. Modification of graphene by chemical means can further expand its uses. Here, liquid-exfoliated graphene is functionalized with p-aminophenyl moiety using p-nitrophenyl diazonium salts which were diazotized in situ then reduced by tin(II) chloride. The aminophenyl-graphene thus produced is further modified to form polyaniline-graphene (PANI-GNH) by in situ oxidative graft polymerization of aniline using ammonium peroxydisulfate as oxidizing agent. The properties of the PANI-GNH were compared with polyaniline/graphene blends by Raman, infrared and UV-Visible spectroscopy, and cyclic voltammetry. Indeed, PANI-GNH registered different spectrochemical and electrochemical properties …

The Mechanism Of Galvanic/Metal-Assisted Etching Of Silicon, Kurt W. Kolasinski

Chemistry Faculty Publications

No abstract provided.

Bubbles: A Review Of Their Relationship To The Formation Of Thin Films And Porous Materials, Kurt W. Kolasinski

Chemistry Faculty Publications

No abstract provided.

Science Classics, Mark Masthay

Chemistry Faculty Publications

An essay on the impact of the works in the Imprints and Impressions: Milestones in Human Progress, an exhibition of rare books from the collection of Stuart Rose. Exhibition was held Sept. 29-Nov. 9, 2014, at the University of Dayton.

Characterizing The Antioxidant Capacity Of Gevalia Traditional Roast Coffee Based On Brew Method, Erica Mendoza

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Modified Seed Growth Of Iron Oxide Nanoparticles In Benzyl Alcohol: Magnetic Nanoparticles For Radio Frequency Hyperthermia Treatment Of Cancer, Stanley E. Gilliland Iii

Theses and Dissertations

Iron oxide nanoparticles have received sustained interest for biomedical applications as synthetic approaches are continually developed for precise control of nanoparticle properties. This thesis presents an investigation of parameters in the benzyl alcohol synthesis of iron oxide nanoparticles. A modified seed growth method was designed for obtaining optimal nanoparticle properties for magnetic fluid hyperthermia. With a one or two addition process, iron oxide nanoparticles were produced with crystallite sizes ranging from 5-20 nm using only benzyl alcohol and iron precursor. The effects of reaction environment, temperature, concentration, and modified seed growth parameters were investigated to obtain precise control over properties …

Fabrication And Characterization Of High Surface Area Gold Electrodes, Madhura S. Damle

Theses and Dissertations

High surface area gold electrodes are very good substrates for biosensors, catalysis and drug delivery. Their performance is characterized by good sensitivity, low detection limit and high signal. As a result, extensive research is being carried out in this field using different approaches of fabrication to generate high surface area porous electrodes of different morphology, pore size and structure. The morphology of the electrodes can be changed based on whether the approach involves a template or not, types of metal deposition, method and time of dealloying etc. The deposition of metal can be carried out using various approaches such as …

Ferroelectric Hexagonal And Rhombic Monolayer Ice Phases, Wen-Hui Zhao, Jaeil Bai, Lan-Feng Yuan, Jinlong Yang, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Two new phases of water, the mid-density hexagonal monolayer ice and the high-density flat rhombic monolayer ice, are observed in our molecular dynamics simulations of monolayer water confined between two smooth hydrophobic walls. These are in addition to the two monolayer ices reported previously, namely, the low-density 4∙8² monolayer ice and the high-density puckered rhombic monolayer ice (HD-pRMI). Stabilities of the structures are confirmed by ab initio computation. Importantly, both new phases and the HD-pRMI are predicted to be ferroelectric. An in-plane external electric field can further stabilize these ferroelectric monolayer ices.

Mos2/Mx2 Heterobilayers: Bandgap Engineering Via Tensile Strain Or External Electrical Field, Ning Lu, Hongyan Guo, Lei Li, Jun Dai, Lu Wang, Wai-Ning Mei, Xiaojun Wu, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We have performed a comprehensive first-principles study of the electronic and magnetic properties of two-dimensional (2D) transition-metal dichalcogenide (TMD) heterobilayers MX₂/MoS₂ (M = Mo, Cr, W, Fe, V; X = S, Se). For M = Mo, Cr, W; X = S, Se, all heterobilayers show semiconducting characteristics with an indirect bandgap with the exception of the WSe2/MoS2 heterobilayer which retains the directbandgap character of the constituent monolayer. For M = Fe, V; X = S, Se, the MX₂/MoS₂ heterobilayers exhibit metallic characters. Particular attention of this study has been focused on engineering the bandgap …

Van Der Waals Trilayers And Superlattices: Modification Of Electronic Structures Of Mos2 By Intercalation, Ning Lu, Hongyan Guo, Lu Wang, Xiaojun Wu, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We perform a comprehensive first-principles study of the electronic properties of van der Waals (vdW) trilayers via intercalating a twodimensional (2D) monolayer (ML = BN, MoSe₂, WS₂, orWSe₂) between a MoS₂ bilayer to form various MoS₂/ML/MoS₂ sandwich trilayers. We find that the BN monolayer is themost effective sheet to decouple the interlayer vdW coupling of the MoS₂ bilayer, and the resulting sandwich trilayer can recover the electronic structures of the MoS₂ monolayer, particularly the direct-gap character. Further study of the MoS₂/BN superlattices confirms the effectiveness of …

Unraveling Crystalline Structure Of High-Pressure Phase Of Silicon Carbonate, Rulong Zhou, Bingyan Qu, Jun Dai, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Although CO₂ and SiO₂ both belong to group-IV oxides, they exhibit remarkably different bonding characteristics and phase behavior at ambient conditions. At room temperature, CO₂ is a gas, whereas SiO₂ is a covalent solid with rich polymorphs. A recent successful synthesis of the silicon-carbonate solid from the reaction between CO₂ and SiO₂ under high pressure [M. Santoro et al., Proc. Natl. Acad. Sci. U.S.A. 108, 7689 (2011)] has resolved a long-standing puzzle regarding whether a Si_xC_1−xO₂ compound between CO₂ and SiO₂ exists in nature. Nevertheless, the detailed …

Photocatalytic Hydrogen Production From A Noble Metal Free System Based On A Water Soluble Porphyrin Derivative And A Cobaloxime Catalyst, Theodore Lazarides, Milan Delor, Igor V. Sazanovich, Theresa M. Mccormick, Irene Georgakaki, Georgios Charalambidis, Julia A. Weinstein, Athanassios G. Coutsolelos

Chemistry Faculty Publications and Presentations

A combination of noble-metal free components, a water soluble porphyrin photosensitizer zincmeso-tetrakis(1-methylpyridinium-4-yl)porphyrin chloride [ZnTMPyP⁴⁺]Cl₄ (1) with cobaloxime complex [Co^III(dmgH)₂(py)Cl] (2) as a catalyst, creates an efficient system for photochemical hydrogen production acting under visible light with 280 TONs. This is the first example of a water soluble porphyrin acting as a photosensitizer for cobaloxime catalysed H₂ production.

Electrode And Electrolyte Additives For Lifetime Extension In Lithium-Ion Batteries, Kishore Anand Narayana

Theses and Dissertations--Chemistry

Lithium-ion batteries (LIBs) are the most commonly used type of rechargeable batteries with a global market estimated at $11 billion, which is predicted to grow to $60 billion by 2020. The global commercialization of Li-ion batteries is impeded by issues such as poor cycle life (5000 cycles achieved in some LIBs) in high energy and power density applications because of the rising internal resistance due to aging and safety concerns such as overcharge which ultimately leads to thermal runaway and explosions. A battery’s performance mainly depends on external factors such as electrode thickness and degree of compacting, and the type …

Addressing Public Health Risks Of Persistent Pollutants Through Nutritional Modulation And Biomimetic Nanocomposite Remediation Platforms, Bradley J. Newsome

Theses and Dissertations--Chemistry

Due to their relative chemical stability and ubiquity in the environment, chlorinated organic contaminants such as polychlorinated biphenyls (PCBs) pose significant health risks and enduring remediation challenges. Engineered nanoparticles (NPs) provide a novel platform for sensing/remediation of these toxicants, in addition to the growing use of NPs in many industrial and biomedical applications, but there remains concern for their potential long-term health effects. Research highlighted herein also represents a transdisciplinary approach to address human health challenges associated with exposure to PCBs and NPs. The objectives of this dissertation research are two-fold, 1) to develop effective methods for capture/sensing and remediation …

Synthesis And Characterization Of Coloumnar Mesophases Of Novel Substituted Dibenzanthracenes And Their Donor-Acceptor Mixtures, Katie M. Psutka

Theses and Dissertations (Comprehensive)

In this thesis, the synthesis and liquid crystalline properties of a series of novel dibenz[a,c]anthracenes are reported. Specifically, two dibenzanthracenecarboxylate derivatives were prepared and were found not to exhibit a mesophase. In contrast, a series of novel N-substituted dibenzanthracenedicarboximides was also synthesized and found to exhibit broad columnar temperature ranges. Several dibenzanthracenedicarboximides substituted with different alkyl chains on the nitrogen atom were prepared and their mesomorphic temperature ranges were characterized. In general, it was found that having a longer, more flexible alkyl chain on the nitrogen atom resulted in a broadening of the columnar temperature range via a lowering …

Concern-Driven Integrated Toxicity Testing Strategies For Nanomaterials - Report Of The Nanosafety Cluster Working Group 10, Hugh Byrne, Agnes G. Oomen, Peter M.J. Bos, Teresa F. Fernandes, Kerstin Hund-Rinke, Diana Boraschi, Karin Aschberger, Stefania Gottardo, Frank Von Der Kammer, Dana Kühnel, Danail Hristozov, Antonio Marcomini, Lucia Migliore

Articles

Bringing together topic-related European Union-(EU)-funded projects, the so-called “NanoSafety Cluster” aims at identifying key areas for further research on risk assessment procedures for nanomaterials (NM). The outcome of NanoSafety Cluster Working Group 10, this commentary presents a vision for concern-driven integrated approaches for the (eco-)toxicological testing and assessment (IATA) of NM. Such approaches should start out by determining concerns, i.e. specific information needs for a given NM based on realistic exposure scenarios. Recognized concerns can be addressed in a set of tiers using standardized protocols for NM preparation and testing. Tier 1 includes determining physico-chemical properties, non-testing (e.g. structure …