Materials Chemistry Commons^™

Preparation Of High Performance Porous Silicon Powders By Etching Al-Si Alloy In Acid Solution For Lithium Ion Battery, Shi-Ji Hao, Chun-Li Li, Kai Zhu, Ping Zhang, Zhi-Yu Jiang

Journal of Electrochemistry

Porous silicon powders prepared by etching Al-Si alloy using an acid solution was reported in the first time. The morphology and structure of as-obtained material were investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD) method. It was found that the spongy porous silicon powders presented well crystalline structure and consisted of nano-Si particles. The particle size of porous Si powders was about 20 μm, and the specific surface area was 102.7 m²·g^-1. The electrochemical properties of porous silicon powders were evaluated as an anode material for lithium ion batteries. The material proportion in the …

Pulse Electrodeposition Of Pd-Ni Alloy Nanoparticles For Electrocatalytic Oxidation Of Formic Acid, Fang-Zu Yang, Jun-Pei Yue, Zhong-Qun Tian, Shao-Min Zhou

Journal of Electrochemistry

The Pd-Ni alloy nanoparticles with nickel atomic contents of 12.0%, 16.4% and 22.6% were successfully electrodeposited from a Pd-Ni alloy electrolyte by square wave pulse plating. The alloy nanoparticles were in the spherical shape with a diameter of 50 ~ 80 nm. As the growth potential of the alloy was negatively shifted, the nickel content of the alloy was increased, and the size of the nanoparticles was almost the same, whereas the number, the degree of crosslinking and the real active area of the nanoparticles were increased. As the nickel content of the alloy nanoparticles increased, the peak current for …

Underpotential Deposition Of Germanium On Au(111) And Pt(111) Surfaces In Ionic Liquids, Xu-Fen Xie, Jia-Wei Yan, Jing-Hong Liang, Ji-Jun Li, Meng Zhang, Bing-Wei Mao

Journal of Electrochemistry

The underpotential deposition (UPD) of germanium (Ge) in BMIPF₆ ionic liquids on Au(111) and Pt(111) surfaces have been investigated by cyclic voltammetry (CV) and in-situ scannin tunneling microscopy (STM). The CV results show that there are two reduction peaks related to the electrodeposition of Ge. The first reduction peak appeared in the CV curve may cover the transformation of Ge⁴⁺ to Ge²⁺ and the UPD of Ge. The second reduction peak corresponds to the bulk deposition of Ge. In-situ STM study suggests that the two UPD layers of Ge are formed on Au(111) and Pt(111) surfaces. The …

Synthesis And Electrochemical Properties Of Lico1-XMgXMno4 And Lico1-XAlXMno4 (X= 0, 0.02, 0.05, 0.1) As Positive Materials For Lithium-Ion Batteries, Mei-Ling You, Qing-Song Tong, Xiu-Hua Li, Min Lin, Xing-Kang Huang, Yong Yang

Journal of Electrochemistry

The Al-doped and Mg-doped LiCoMnO₄ materials were synthesized through solid-state reaction. The effects of doping amounts of Mg and Al on the initial capacities, discharge plateaus, and cycle performances were investigated. The morphologies and structures of the as-prepared materials were studied by scanning electron microscopy and powder X-ray diffraction. The results indicate that the as-prepared samples were composed of uniform, well-crystallized particles. The pristine LiCoMnO₄ possessed an initial capacity of 87.0 mAh·g^-1, while LiCo_0.98Mg_0.02MnO₄ and LiCo_0.98Al_0.02MnO₄ delivered 91.3 and 93.6 mAh·g^-1, respectively. The proper …

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.