Physical Chemistry Commons^™

Multi-Scaled Carbon Supported Platinum As A Stable Electrocatalyst For Oxygen Reduction Reaction, Yu-Ping Li, Lu-Hua Jiang, Su-Li Wang, Gong-Quan Sun

Journal of Electrochemistry

The stability of carbon supports is essential for electrocatalysts of fuel cells. Herein, the mesoporous carbon with the high graphitic degree (highly graphitic mesoporous carbon, HGMC) was synthesized by using resorcinol as the carbon precursor, SiO₂ as the templates and urea as the reducing agent. The as-prepared HGMC was characterized by XRD, Raman spectroscopy, TEM, N2 adsorption. The stability of HGMC was evaluated by mimicking the start-up/shut-down conditions of fuel cells in a three-electrode system referring to the NREL standard. The obtained HGMC is of moderate surface area (187.4 m²•g^-1) and is chemically stable under …

Recycling Mf Solid Waste Into Mesoporous Nitrogen-Doped Carbon With Iron Carbide Complex In Graphitic Layers As An Efficient Catalyst For Oxygen Reduction Reaction, Can-Yun Zhao, Lin Huang, Yong You, Ying-Fang Yao, Xiao-Gang Su, Hong Wan, Jian-Guo Liu, Cong-Ping Wu

Journal of Electrochemistry

Nitrogen-doped carbon materials with iron ions are known as catalytic growth agents for the oxygen reduction reaction (ORR) in fuel cells, but the design and synthesis of high-performance and low-cost catalysts still remain a significant challenge. Herein, we present a cost-effective approach to dispose of MF solid waste as the precursor for the synthesis of MCFes catalyst with the favorable structure features such as the high specific surface area, abundant active sites and suitable pore structure. The results showed that the MCFe-10/10/2 had specific surface area as high as 780.7 m²•g^-1 and high efficient catalytic activity comparable …

Synthesis Of Structurally Ordered Platinum-Iron Catalysts With Enhanced Oxygen Reduction Reaction Activity, Ye-Zheng Cai, Ming-Chuan Luo, Fang-Hui Wang, Zhao-Nan Sun, Hong Zhu

Journal of Electrochemistry

To improve oxygen reduction reaction catalytic activity of the precious metals platinum for fuel cell, the precursors of carbon-supported structurally disordered platinum-iron alloy (D-Pt₃Fe/C and D-PtFe/C) catalysts with different compositions were synthesized via a modified polyol reduction method. Then, by optimizing the annealing conditions in the inert gas, we turned the structurally disordered platinum-iron alloy to the structurally ordered platinum-iron alloy (O-Pt₃Fe/C and O-PtFe/C) catalysts. The structural characterizations of the as-prepared catalysts were performed by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and X-ray photoelectron spectroscopy (XPS). The results …

Recent Progresses In Molybdenum-Based Electrocatalysts For The Hydrogen Evolution Reaction, Ze-Xing Wu, Jie Wang, Jun-Po Guo, Jing Zhu, De-Li Wang

Journal of Electrochemistry

Electrochemical catalytic production of hydrogen has been considered as a promising and sustainable strategy for clean and renewable energy technologies. Molybdenum-based non noble metal catalysts for the hydrogen evolution reaction have attracted extensive attention due to its effective catalytic performance. In this review, the recent progresses in molybdenum-carbide, phosphide, nitride and sulfide electrocatalysts are presented. In addition, the strategies to improve the catalytic performance are analyzed and the prospects for the future development trends are expected.

Nitrogen, Fluorine Co-Doped Silk-Derived Carbon For Electrochemical Oxygen Reduction With High Performance In Alkaline Solution, Fang-Fang Liu, Hong-Liang Peng, Shi-Jun Liao

Journal of Electrochemistry

A high-performance, doped carbon-based catalyst was synthesized by pyrolyzing hydrothermally treated silkworm cocoon. The effects of preparation conditions and fluorine promotion on various catalysts’ performance were investigated. The catalyst prepared under optimal conditions and doped with nitrogen and fluorine possessed the high specific surface area of more than 1000 m^2⋅g^-1 and contained 3.5 and 7.3% (by mass, the same below) N and F, respectively. The activity of the catalyst toward oxygen reduction reaction in an alkaline medium was comparable to that of commercial Pt/C, showing both superior tolerance to methanol poisoning and better durability. Doping with fluorine …

Binding Of Oxygen To Human Hemoglobin Within The Erythrocyte Using Icam Spectrophotometry, Kyle K. Hill

Department of Chemistry: Dissertations, Theses, and Student Research

Many of the spectrophotometric techniques used to determine the properties of intracellular human hemoglobin cannot be utilized due to the turbidity of erythrocyte suspensions. An Integrating Cavity Absorption Meter, or ICAM, allows for absorption measurements of strongly scattering samples in the visible-light region of the spectrum. The spectrum of oxygenated hemoglobin within erythrocytes is significantly different from the absorption spectrum of oxygenated hemoglobin in solution. Studies of the oxygen binding to hemoglobin in erythrocytes allowed the four sequential binding constants (Adair constants) to be determined and compared with those of hemoglobin in solution. The Adair constants for hemoglobin in solution …

Understanding The Surface Induced Phosphorylation Of Prebiotic Molecules By Schreibersite, Danna Qasim

Master of Science in Chemical Sciences Theses

The study of the surface of a meteoritic mineral, schreibersite (Fe,Ni)₃P, was investigated to provide insight into the role of the mineral’s surface in aqueous-phase phosphorylation reactions. The optimization of a custom-designed ultrahigh vacuum (UHV) apparatus and Fe₂NiP (schreibersite) surface was performed to permit surface science analysis. The bare surface was characterized by scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS), which showed some oxidation and segregation of phosphorous within the near-surface region. The interaction and/or reaction of water (H₂O), methanol (CH₃OH), formic acid …

Is The Maxwell Construction Correct In Predicting The Van Der Waals Fluid's Vapor Pressure?, Carl W. David

Chemistry Education Materials

The Maxwell construction yields a pressure value which traditionally been associated with the vapor pressure. Here, the question is answered whether or not the two phases represented by the construct are indeed in equilibrium.

Photocatalytic Properties Of G-C3n4–Tio2 Heterojunctions Under Uv And Visible Light Conditions, Rachel Fagan, Declan Mccormack, Steven J. Hinder, Suresh Pillai

Articles

Graphitic carbon nitride (g-C3N4) and titanium dioxide (TiO2) were chosen as a model system to investigate photocatalytic abilities of heterojunction system under UV and visible light conditions. The use of g-C3N4 has been shown to be effective in the reduction in recombination through the interaction between the two interfaces of TiO2 andg-C3N4. A simple method of preparing g-C3N4 through the pyrolysis of melamine was employed, which was then added to undoped TiO2 material to form the g-C3N4–TiO2 system. These materials were then fully characterized by X-ray diffraction (XRD), Brunauer Emmett Teller (BET), and various spectroscopic techniques including Raman, X-ray photoelectron …

Photocatalytic Reduction Of Fumarate To Succinate On Zns Mineral Surfaces, Ruixin Zhou, Marcelo I. Guzman

Chemistry Faculty Publications

The reductive tricarboxylic acid (rTCA) cycle is an important central biosynthetic pathway that fixes CO₂ into carboxylic acids. Among the five reductive steps in the rTCA cycle, the two-electron reduction of fumarate to succinate proceeds nonenzymatically on the surface of photoexcited sphalerite (ZnS) colloids suspended in water. This model reaction is chosen to systematically study the surface photoprocess occurring on ZnS in the presence of [Na₂S] (1–10 mM) hole scavenger at 15 °C. Experiments at variable pH (5–10) indicate that monodissociated fumaric acid is the primary electron acceptor forming the monoprotic form of succinic acid. The following …

Enhancing The Photovoltaic Efficiency Of A Bulk Heterojunction Organic Solar Cell, Swapnil Ashok Sahare

Masters Theses & Specialist Projects

Active layer morphology of polymer-based solar cells plays an important role in improving power conversion efficiency (PCE). In this thesis, the focus is to improve the device efficiency of polymer-based solar cells. In the first objective, active layer morphology of polymer-solar cells was optimized though a novel solvent annealing technique. The second objective was to explore the possibility of replacing the highly sensitive aluminum cathode layer with a low-cost and stable alternative, copper metal. Large scale manufacturing of these solar cells is also explored using roll-to-roll printing techniques.

Poly (3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl (PCBM) were used as the …

Mutlifunctional Platforms For Gene And Drug Delivery For Cancer Therapy, Jeffery J. Ambrose Jr.

Doctoral Dissertations

The National Cancer Institute and the American Cancer Society estimate that 1.6 million new cancer incidences and over half a million cancer related deaths occur annually [1][2]. Cancer the second most common cause of death in the United States [1], [2]. Although the causes of cancer can vary depending on cell type, all or almost all instances of cancer arise from a mutation or from an abnormal activation of the cellular genes that control cell growth and mitosis [3].

Treatment of a given cancer type depends on the subtype, stage and progression of the cancer. Varieties of cancer therapy include …

Novel Mitochondrial Complex I Inhibitors Restore Glucose-Handling Abilities Of High-Fat Fed Mice, Darren Martin, Siobhan Leonard, Robert Devine, Clara Redondo, Gemma Kinsella, Conor Breen, Victoria Mceneaney, Mary Rooney, Tim Munsey, Richard Porter, Asipu Sivaprasadarao, John Stephens, John Findlay

Articles

Metformin is the main drug of choice for treating type 2 diabetes, yet the therapeutic regimens and side effects of the compound are all undesirable and can lead to reduced compliance. The aim of this study was to elucidate the mechanism of action of two novel compounds which improved glucose handling and weight gain in mice on a high-fat diet. Wildtype C57Bl/6 male mice were fed on a high-fat diet and treated with novel, anti-diabetic compounds. Both compounds restored the glucose handling ability of these mice. At a cellular level, these compounds achieve this by inhibiting complex I activity in …

Xiao Cheng Zeng Bibliography (April 2016), Xiao Cheng Zeng

Xiao Cheng Zeng Publications

397 articles sorted by topics

Novel Numerical Models Of Electrostatic Interactions And Their Application To S-Nitrosothiol Simulations, Maxim Vadimovich Ivanov

Dissertations (1934 -)

Atom-centered point charge model of the molecular electrostatics remains a major workhorse in the atomistic biomolecular simulations. However, this approximation fails to reproduce anisotropic features of the molecular electrostatic potential (MEP), and the existing methods of the charge derivation are often associated with the numerical instabilities. This work provides an in-depth analysis of these limitations and offers a novel approach to describe electrostatic interactions that paves the way toward efficient next-generation force fields. By analyzing the charge fitting problem from first principles, as an example of the mathematical inverse problem, we show that the numerical instabilities of the charge-fitting problem …

Characteristic Length Scales Of The Secondary Relaxations In Glass-Forming Glycerol, Sudipta Gupta, Eugene Mamontov, Niina Jalarvo, Laura Stingaciu, Michael Ohl

Faculty Publications

We investigate the secondary relaxations and their link to the main structural relaxation in glass-forming liquids using glycerol as a model system. We analyze the incoherent neutron scattering signal dependence on the scattering momentum transfer, Q , in order to obtain the characteristic length scale for different secondary relaxations. Such a capability of neutron scattering makes it somewhat unique and highly complementary to the traditional techniques of glass physics, such as light scattering and broadband dielectric spectroscopy, which provide information on the time scale, but not the length scales, of relaxation processes. The choice of suitable neutron scattering techniques depends …

An Effective Method For The Preparation Of High Temperature Stable Anatase Tio2 Photocatalysts, Rachel Fagan, Declan Mccormack, Suresh Pillai, Damian Synnott

Articles

An efficient, rapid and straightforward method for the preparation of nitrogen and fluorine (N, F) codoped high temperature stable anatase using a microwave pre-treatment is reported. Using a single source, ammonium fluoride (NH₄F) for both nitrogen and fluorine, effective doping of the precursor titanium isopropoxide (TTIP) was possible. These samples were characterised for their structural and optical properties using X-ray diffraction (XRD), Fourier transform IR (FTIR), Raman spectroscopy and UV-vis spectroscopy. In terms of the anatase to rutile transition enhancement using a novel microwave assisted technique, the sample prepared in a composition of 1:8 TiO₂: NH …

Electrochemical H2O2 Sensor Based On The Co-Immobilization Of Phosphmolybdic Acid And Graphene On Pedot Film Electrode With Nafion, Hao-Xian Zhou, Jun-Ming Zhang, Zhi-Yu Qu, Pan-Yu Zhang, You-Jun Fan

Journal of Electrochemistry

With a glassy carbon electrode (GCE) as the substrate, the poly(3,4-ethylenedioxythiophene) (PEDOT) film electrode was prepared through the electrochemical polymerization method, then a novel non-enzymatic electrochemical H₂O₂ sensor was fabricated by co-immobilizing phosphomolybdic acid and graphene with Nafion on the PEDOT/GCE electrode. The modified electrodes were characterized by scanning electron microscopy (SEM), while the responsive properties of the sensor to H₂O₂ were investigated by cyclic voltammetry and chronoamperometry. The results demonstrated that, under the optimized conditions, the sensor exhibited good electrocatalytic performance for H₂O₂ reduction. The current response of the sensor …

Improving The Electrochemical Properties Of Polyaniline By Doping With Silver Ions, Hui Xu, Jin-Juan Pu, Yong Chen, Jian Liu

Journal of Electrochemistry

Polyaniline (PANI) is an attractive candidate among the various conductive polymers based on its unique doping/de-doping behavior, intrinsic electrical conductivity, facile synthesis, and environmental stability. However, the poor conductivity and cycle stability in an acid medium have restricted its applications. Our work aims at solving the above problems effectively by doping silver ions into PANI. The PANI and PANI doped with silver ions (PANI/Ag⁺) were synthesized by a facile interfacial polymerization process, which used aniline as a starting material in toluene in contact with an aqueous solution of silver nitrate varied from 0.04 mol•L^-1 to 0.20 mol⋅L …

The Study On Comparison Of Electrochemical Performance In Microbial Fuel Cell With Glucose And Sodium Acetate Acting As Substrates, Lei Fan, Yu Zhao, Ting Li, Qin-Bo Yuan, En-Zhi Wang, Xiao-Bin Wang, Jun-Wen Wang

Journal of Electrochemistry

By inoculating aerobic sludge and anaerobic sludge from the sewage treatment plant, two sets of dual-chamber microbial fuel cells (MFCs) were built with either glucose or sodium acetate acting as a substrate. Accordingly, the electrochemical performances of MFCs were explored with the concentration of the substrates being 0.0335 mol⋅L^-1. The results of the comparative study in glucose system and sodium acetate system showed that the impedance values of anodic half cell were 222 Ω for glucose and 213.67 Ω for sodium acetate, implying no significant effect on the internal resistance in battery with the different substrates. The exchange …