bluuebunny/crossref_metadata_2025_split huggingface dataset:
Peroxynitrite Sensing: From Graphene-Based Platforms to Modified Boron-Doped Diamond Electrodes
Authors: Bayachou Mekki , Kalil Haitham 
Published: February 2020

Peroxynitrite (PON) is a major cytotoxic agent, implicated in a host of pathophysiological conditions. In biological systems, peroxynitrite is the primary product of the reaction of superoxide ion and nitric oxide, and has been lately at the forefront of investigations dealing with nitroxidative stress. One major challenge in the analytical determination of peroxynitrite under physiologic conditions is its short half-life and its fast reactivity with many cellular targets. Spectroscopic and other detection methods for peroxynitrite have been proposed but face the problem of real-time quantification and particularly when localized measurements are needed. We have shown that catalyzed electrochemical detection of peroxynitrite is a simpler and more convenient technique. In the past, we described the use of polymerized hemin (iron protoporphyrin IX) and other porphyrins on graphite electrodes as platforms for amperometric measurement of peroxynitrite both in still solutions and under flow conditions. This work has been extended to reduced graphene oxide functionalized with hemin as a catalytic platform for PON oxidative detection. Boron-doped diamond electrodes (BDD) have been used as platforms for electrochemical detection of a number of analytes in environmental samples as well as in biological media. BDD electrodes have the advantage to provide a relatively wide electrochemical window as well as low capacitive currents. In the present paper we compare and contrast the direct electrochemical oxidation of peroxynitrite on BDD and the catalytic oxidation of PON on modified diamond electrodes as potential sensing platforms of PON. Boron-doped diamond based microarray electrodes have been proposed as potential devices for neuronal stimulation. We hypothesize that PON generated at the array-tissue interface is a major cytotoxic intermediate leading to ultimate tissue death. Developing sensing electrodes based on catalytic detection of PON on boron-doped diamond electrodes is a step towards using individually addressable electrodes in a BDD electrode array for both electrical stimulation and monitoring of PON levels as a predictor of tissue deterioration and, ultimately, death. Understanding the fundamental processes involved during the catalytic oxidation of PON on modified BDD offers the possibility to fine-tune the surface to optimize PON detection.
A New Kind of SERS Active Substrate Using a Film of Densely Packed Gold Nanoparticles
Authors: Rutherford Gugu , Farrell Monique , Xiao Bo , Carvajal Christian G , Santiago Kevin , Pradhan Aswini K 
Published: February 2020

In the past two decades there has been a developing interest in using surface plasmon resonance materials for biosensors, environmental sensors, and medical devices due to their ability to identify lower concentrations of analytes. Surfaced Enhanced Raman Spectroscopy has been a useful technique to understand the plasmonic behavior of materials. This research team has developed a novel method for fabricating a highly densely packed film of green synthesized gold nanoparticles using UV irradiation with a UV light source at 254nm and 185 nm. Raman spectroscopy was used to characterize the densely packed film, and the surface of the film was functionalized with Rhodamine 6G probe molecules to monitor the SERS activity and identify an enhancement factor. Various proteins were immobilized to the surface of the densely packed gold nanoparticle film, and a SERS measurement was taken to identify the films capability of detecting low concentration of proteins. This experimental data has shown the proof of concept for the development of a cost effective and simple method to fabricate SERS substrates specifically for the development of biosensors for the detection of proteins.
Application of PVC Membrane Sensor in Pharmaceutical and Environmental Analysis. One Example: Potentiometric Determination of Moxifloxacin in Some Pharmaceutical Formulation Using PVC Membrane Sensors
Authors: Mostafa Gamal Abdel-Hafiz 
Published: February 2020

PVC membrane sensor using different approach e.g. ion-pair, ionophore, and schiff-base has been used as testing membrane sensors. Analytical applications of membrane sensors for direct measurement of variety of different ions in complex biological and environmental sample are reported. The most important step of such PVC membrane sensor is the sensing active material. The potentiometric sensors have some outstanding advantages including simple design, operation, wide linear dynamic range, relative fast response time, and rotational selectivity. The analytical applications of these techniques to pharmaceutical compounds in dosage forms are also discussed.
The construction and electrochemical response characteristics of Poly (vinyl chloride) membrane sensors for moxifloxacin HCl (MOX) are described. The sensing membranes incorporate ion association complexes of moxifloxacin cation and sodium tetraphenyl borate (NaTPB) (sensor 1), phosphomolybdic acid (PMA) (sensor 2) or phosphotungstic acid (PTA) (sensor 3) as electroactive materials. The sensors display a fast, stable and near-Nernstian response over a relative wide moxifloxacin concentration range (1 ×10-2 - 4.0×10-6, 1 × 10-2 - 5.0×10-6, 1 × 10-2 - 5.0×10-6 M), with detection limits of 3×10-6, 4×10-6 and 4.0×10-6 M for sensor 1, 2 and 3, respectively over a pH range of 6.0 - 9.0. The sensors show good discrimination of moxifloxacin from several inorganic and organic compounds. The direct determination of 400 mg/ml of moxifloxacin show an average recovery of 98.5, 99.1 and 98.6 % and a mean relative standard deviation of 1.8, 1.6 and 1.8% for sensors 1, 2 and 3 respectively. The proposed sensors have been applied for direct determination of moxifloxacin in some pharmaceutical preparations. The results obtained by determination of moxifloxacin in tablets using the proposed sensors are comparable favorably with those obtained using the US Pharmacopeia method. The sensors have been used as indicator electrodes for potentiometric titration of moxifloxacin.
X-Ray Photoelectron Spectroscopy and Raman Scattering Studies of ALD Alumina Coated ZnTe Nanowires
Authors: Pradhan Kallol , Sahoo Satyaprakash , Peng J H , Yu H , Dey S K , Katiyar Ram S. 
Published: February 2020

Semiconductor nanowires (NWs) represent a versatile platform for evaluating novel phenomena at the nanoscale and also exhibit high potential for applications in future electronic, photovoltaic, and optoelectronic devices [1]. Moreover, the fabrication of core-shell heterostructures based on semiconductor NW-insulator heterostructures further enable the generation of devices with diverse functions. In this work, the fabrication of core-shell heterostructures, via metal-catalyzed vapor–liquid–solid synthesis of Zinc Telluride (ZnTe) NWs followed by the conformal coating of alumina (Al2O3) by atomic layer deposition (ALD), has been demonstrated. While the former is a direct band gap (~ 2.26 eV), II-VI semiconductor in the blue-green region of the spectrum, the latter is a high band gap (~ 6.4 eV) insulator that is amorphous. Here, preliminary x-ray photo electron spectroscopy (XPS) and Raman scattering results on the ZnTe/Al2O3 core-shell nanostructures are presented and discussed. Additionally, photoluminescence spectra of coated and uncoated ZnTe NWs are discussed in light of the variations in peak position and line-width.
Reference:
1. J. Wallentin, et al, InP nanowire array solar cells achieving 13.8 % efficiency by exceeding the ray optics limit,
Science 339, pp. 1057-1060, (2013).
Preparation of Buckypaper By Surface Modified Multi-Walled Carbon Nanotubesfor Oxygen Reduction Reaction in PEMFC
Authors: Ye Licheng , Zheng Junsheng , Li Ping , Gao Yuan 
Published: February 2020

As the key material of proton exchange membrane fuel cell (PEMFC), the carbon supported Pt nanoparticles are the most widely used catalyst for cathode and anode of PEMFC.
Recently we reported anultra-low Pt loading catalytic layer based on buckypaper for oxygen reduction reaction1. The buckypaper is a double-layer thin film containing a multi-walled carbon nanotubes rich surface and a carbon nanofibers rich surface. And Pt has a gradient distribution in this catalytic layer in order to reduce the Pt content.
In this paper, varies of surface modification methods for MWNTs,such as oil-bath acidic reflux, ultrasonic and microwave treatment, were systematically studied,and the oxygen reduction activity of those treated MWNTs were measured. The results showed that surface modified MWNTs have better oxygen reduction reaction activity than the as received MWNTs. Among those treatments, microwave treated MWNTs have better performance than other treatments. Next step buckypaper will be prepared by surface modified MWNTs. As surface modification can also enhance the dispersion of the catalyst2, it has a potential to show good ORR performance in a low Pt loading thus reduce the cost of catalyst.

Acknowledgments

The authors acknowledge the support from the Shanghai Rising-Star Program (11QA1407200), the National Natural Science Foundation of China (21006073), the Scholarship Council and the Fundamental Research Funds for the Central Universities at Tongji University.

Reference

J.Zheng, T.Tian,Y. Gao, Q. Wu, J. Ma, J. Zheng. Int. J. Hydrogen.Energ, 39(2014) 13816.

Y. Xing, L. Li, C. Chusuei, R. Hull. Langmuir, 21 (2005) 4185.

Figure 1
(Invited) Non-Resonant Absorption in Carbon Nanotubes
Authors: Vialla Fabien , Malic Ermin , Langlois Benjamin , Chassagneux Yannick , Lauret Jean-Sébastien , Voisin Christophe 
Published: February 2020

Absorption spectroscopy of large ensembles of carbon nanotubes show marked resonances, attributed to the different exitonic levels of each chiral species, as well as a relatively smooth background. This signal consists of a large number of different intrinsic and extrinsic contributions, such as phonon sidebands, amorphous carbon absorption, light scattering... It is therefore challenging to extract any quantitative information from these direct absorbance measurements.
In contrast, photoluminescence excitation measurements in semi-conducting nanotubes give access to the intrinsic non-resonant absorption contribution between the excitonic resonances. Using a global analysis method, we were able to delineate the contribution of each chiral species including its tiny non-resonant component that shows up as 0.5 eV wide plateaus between the excitonic resonances. By comparison with the recently reported excitonic absorption cross-section on the S22 resonance, we found a universal non-resonant absorption which turns out to be of the order of one half of that of an equivalent graphene sheet. This value as well as the absorption line-shape in the non-resonant window is in excellent agreement with microscopic calculations. This non-resonant absorption cross-section is the same (within our resolution) for all the chiral species we measured in this study.
Hydrogen-Bromine RFB :Electrochemical Measurements and Cell Performance of a 40cm² H/Br-RFB System
Authors: Küttinger Michael , Noack Jens , Elazari Ran , Costi Ronny , Tübke Jens 
Published: February 2020

Conventional redox flow batteries (RFB) use electrolyte solutions as energy storage media. For this reason the energy density is mainly limited by the solubility of the redox couples in the solutions. The kinetics of the reactions is mostly moderate so that cycling power densities can only reach max. 100 mW/cm². Depending on the energy / performance ratio the cost of the energy converter of RFBs clearly dominates the total investment costs. For longer storage periods the influence of the cost of the energy storage medium increases. For these reasons RFBs with redox pairs with high kinetics and thus a high power density are desirable. Hydrogen and bromine-based energy storage fulfill both requirements because the kinetics of the reactions are very fast and both elements are inexpensive and very abundant. In addition potentially high energy densities and efficiencies can be achieved.
Anode: H2 -> 2 H+ +2 e- E0 = 0.00 V
Cathode: Br2 +2 e- -> 2 Br- E0 = + 1.06 V
Cell: H2 + Br2 -> 2 HBr E = 1.06 V
Although the first studies were made in the 80s of the last century [1], the research intensified due to these positive characteristics in the last years [2, 3]. For a viable use, hydrogen storage, bromine diffusion, bromine complexation and system behavior are the biggest challenges.
In this work we want to present the results of the development and the construction of an H/Br-RFB with an active area of 40 cm² and its behavior at different electrolyte compositions, temperatures and current densities. For better identification of the properties the half-cell potentials and impedances were also measured and evaluated. This research forms the basis for our future studies involving the use of advanced bromine complexation agents (BCAs) and their impact on H/Br-RFB.
[1] Yeo, R. S.; Chin, D. ‐T. (1980): A Hydrogen‐Bromine Cell for Energy Storage Applications. In: Journal of The Electrochemical Society 127 (3), S. 549–555. DOI: 10.1149/1.2129710.
[2] Cho, Kyu Taek; Albertus, Paul; Battaglia, Vincent; Kojic, Aleksandar; Srinivasan, Venkat; Weber, Adam Z. (2013): Optimization and Analysis of High-Power Hydrogen/Bromine-Flow Batteries for Grid-Scale Energy Storage. In: Energy Technology 1 (10), S. 596–608. DOI: 10.1002/ente.201300108.
[3] Cho, Kyu Taek; Tucker, Michael C.; Ding, Markus; Ridgway, Paul; Battaglia, Vincent S.; Srinivasan, Venkat; Weber, Adam Z. (2014): Cyclic Performance Analysis of Hydrogen/Bromine Flow Batteries for Grid-Scale Energy Storage. In: ChemPlusChem, S. n/a. DOI: 10.1002/cplu.201402043.

Figure 1
Solid Particle Flow Battery Design and Characterization
Authors: Koenig Gary , Qi Zhaoxiang 
Published: February 2020

Classic flow battery systems have consisted of transition metals dissolved in aqueous solvents which provide the electroactive materials. These flow battery systems have relatively low energy densities due to the stability window of water limiting the operating voltage and the solubility of the transition metals limiting the practical capacity. Recently, a few research groups have explored flow batteries with solid particles as the electroactive materials, in an effort to increase the energy density of the catholyte and anolyte materials. Many of these reported systems have extremely high viscosities because of the high solid particle loadings in the electrolyte. These high viscosities will result in high energy demands for the pumping of the electroactive fluids. Our group has been working on flow battery systems that take advantage of the energy density advantages of solid particles, but with a goal of not having prohibitive parasitic energy losses from pumping these fluids through the flow battery system. This work will describe the design and characterization of a flow battery that operates at reasonable viscosities for a particle-laden electrolyte, and the observed coupling between electrochemical properties and rheological properties in a solid particle flow battery system.
Feasibility of All-Copper Hybrid Redox Flow Battery for Large Scale Energy Storage
Authors: Stricker Elizabeth A. , Savinell Robert F. , Wainright Jesse S. 
Published: February 2020

Copper redox flow batteries have been newly studied and offer many advantages over other redox flow battery chemistries [1-3]. There is little hydrogen evolution, no dendrite formation has been observed, and it is an all copper system which indicates no crossover contamination. Preliminary analysis indicates an open circuit voltage of 0.81 volts as shown in Figure 1.Although the all copper redox flow battery has a relatively low open circuit voltage, the all copper redox flow batter provides a platform for a simple and cost-effective flow battery system. In this research, the all copper redox flow battery in bromide electrolyte has been studied in a prototype 6.45 cm2electrode single cell. Charge-discharge cycling achieved coulombic efficiencies over 85% and voltaic efficiencies greater than 75%. However, capacity fade was observed and preliminary results suggest this is due to metallic copper loss at the negative electrode. This is most likely due to non-ideal plating morphologies which have been studied independently as a function of current density and electrolyte composition. We will report on our cell testing and single electrode experiments for this promising flow battery chemistry.

Figure 1: Cyclic voltammogram of 0.5M Cu1+ in 4M NaBr, 1M HBr, and 0.5M Br-. This is the last of 5 cycles at a scan rate of 10 mV/s, on a graphite working electrode, and using a silver-silver chloride reference electrode. The Cu0/1+ and Cu1+/2+ standard potentials are approximately -0.26 and 0.55 volts, respectively indicating the all copper redox flow battery has an open circuit potential of 0.81 volts.

References:
[1] D. Lloyd, T. Vainikka, K. Kontturi, Electrochimica Acta, 100 (2013) 18-23.
[2] L. Sanz, D. Lloyd, E. Magdalena, J. Palma, K. Kontturi, Journal of Power Sources, 268 (2014) 121-128.
[3] L. Sanz, D. Lloyd, E. Magdalena, J. Palma, M. Anderson, K. Kontturi, Journal of Power Sources, 278 (2015) 175-182.

Figure 1
Surface Modified Activated Carbons Prepared from Orange Peel Waste As Potential Electrodes for Li-Ion Capacitors
Authors: Arie Arenst Andreas , Lee Joong-Kee , Halim Martin , Kristianto Hans 
Published: February 2020

In this work, orange peel waste was used as the precursor for activated carbon-based electrodes for Li-Ion Capacitors. Initially, activated carbons were prepared by chemical activation process using ZnCl2. The surface of the activated carbon was then modified with the oxidative chemical agents (H2SO4, HNO3, H2O2 and KOH solutions). The morphology, surface chemical composition, and surface area of the surface modified carbon materials were studied by scanning electron microscope, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller measurement, respectively. Electrochemical characteristics of the as-prepared sample were investigated by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy measurements. Experimental results showed that the surface modification had a very significant effect on the improvement of electrochemical characteristics of activated carbon as electrodes in supercapacitors. The good electrochemical performance of the activated carbon was attributed to well-developed micropores, high surface area, the presence of oxygen functional groups, and larger pore volume.The results indicate that orange peel waste can potentially be applied as a raw material for the production of low cost activated carbon electrode materials for Li-Ion Capacitors.
Cobalt Nanoparticles Embedded in Porous Carbon Nanofibers As Bifunctional Electrocatalysts for Oxygen Reduction and Evolution Reactions
Authors: Singhal Richa , Kalra Vibha 
Published: February 2020

Increasing demand for clean and sustainable energy has accelerated research on alternative energy production and storage systems with high efficiency, low cost, and environmental benignity. Various renewable energy technologies such as fuel cells, metal-air batteries, and water splitting require efficient catalysts for oxygen reduction and evolution reactions. In the past, various precious (expensive) and non-precious metal catalysts have been studied as efficient ORR or OER catalysts, while only a few studies have reported bifunctional catalysts for both ORR and OER. Hence, it is highly challenging and desirable to develop low cost and bifunctional catalyst with high ORR and OER activity.
In the present study, cobalt nanoparticles embedded in porous carbon nanofibers have been reported as an efficient bifunctional electrocatalyst for both ORR and OER in alkaline medium. The polymer solution consisting of polyacrylonitrile (as carbon precursor), Nafion (as sacrificial polymer) and cobalt carbonate (as cobalt precursor) in DMF was electrospun to form nanofibers. During pyrolysis to 1000 °C in inert atmosphere, Nafion decomposes out to form porous carbon nanofibers, while cobalt carbonate reduces to cobalt oxide. Cobalt oxide is further reduced to cobalt by reduction in hydrogen at 500 °C. Thus, a stable, synergistic catalyst combining the high ORR activity of porous carbon nanofibers and the excellent OER activity of cobalt nanoparticles is obtained. The electrochemical tests on the fabricated materials were carried out using a rotating disc electrode setup. It was found that the hybrid catalyst exhibits comparable ORR activity to a commercial carbon-supported precious Pt catalyst (20wt% on Vulcan carbon) and improved OER activity than 20wt%Ir/C and 20wt% Ru/C in alkaline solutions. Such a high activity is attributed to the uniform distribution of cobalt nanoparticles within the porous carbon nanofiber matrix providing high surface area and efficient charge transfer ability.
Fig. 1. Comparison of ORR and OER activities of cobalt-porous carbon nanofibers (Co-PCNFs) with that of commercial Pt/C.
*Singhal, R. and Kalra, V. Electrospun porous carbon nanofibers embedded with cobalt nanoparticles as an excellent bifunctional electrocatalyst for oxygen reduction and evolution reactions, to be submitted.

Figure 1
A Spatially Resolved PEM Fuel Cell Catalyst Degradation Study Under Automotive Load Cycle for Durability Prediction
Authors: Mayur Manik , Quinaud Manuelle , Bessler Wolfgang G. 
Published: February 2020

One of the limiting bottlenecks of polymer electrolyte membrane fuel cell (PEMFC) technology to create a breakthrough in cost-effectiveness and lifetime in automotive applications is the highly load-sensitive degradation of cell components. Most of the cell performance evaluation on the single cell or system level provides only an averaged insight into cell voltage and current values, and does not reveal the spatial behavior of the cell state variables. Since, the reported cell failure cases in the literature show highly localized cell component degradation, an averaged analysis will not be able to provide a thorough insight in the causes of the cell failure, nor to propose mitigation strategies. The spatial distribution of reactants concentration and pressure gradients in the flow field leads to a spatially varying cell operating behavior. This creates specific zones of variable performance in the membrane electrode assembly (MEA). Hence, one can observe the redistribution of the local current density, leading to uneven reactant utilization, reduced overall efficiency, and localized accelerated degradation [1,2].
In this study, with the help of a 2D multiphysics model [3] of a single cell, we can not only have a high spatio-temporal resolution of the fuel cell state variables, but also a detailed insight in the spatial degradation of cell component properties. In particular, we study the loss of electro-chemical active surface area (ECSA) based on an electrochemical degradation reaction mechanisms. The degradation is quantified spatially resolved along the flow length. Using an in-house system model of a car, we expose the fuel cell model to a highly transient loading cycle (New European Driving Cycle). Using a time-upscaling methodology, we present a predictive analysis of cell end-of-life under different operating conditions.

References:

1. C. Robin, M. Gerard, A. A. Franco, and P. Schott, “Multi-scale coupling between two dynamical models for PEMFC aging prediction,” International Journal of Hydrogen Energy 38, 4675–4688 (2013).
2. J. Dillet, D. Spernjak, A. Lamibrac, G. Maranzana, R. Mukundan, J. Fairweather, S. Didierjean, R. L. Borup, and O. Lottin, “Impact of flow rates and electrode specifications on degradations during repeated startups and shutdowns in polymer-electrolyte membrane fuel cells,” Journal of Power Sources 250, 68–79 (2014).
3. C. Bao and W. G. Bessler, “Two-dimensional modeling of a polymer electrolyte membrane fuel cell with long flow channel. Part I. Model development,” Journal of Power Sources 275, 922–934 (2015).