bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gold Nanoparticle Embedded Modified MWCNT Electrodes for Electrochemical Detection of Arsenic in Water
Authors: Mitra Shirsendu , Roy Nirmal , Bandyopadhyay Dipankar 
Published: February 2020

Email of corresponding author: dipban@iitg.ac.in

Abstract: We focus on electrochemical detection of arsenite and/or arsenate in water using different kinds of electrodes made from gold nanoparticle embedded on substituted multiwall-carbon-nanotubes (MWCNT). The CNTs were functionalised with thiol groups by reaction with cysteamine. Following this, three different electrodes were fabricated using thiol substituted MWCNTs, gold nanoparticle (Au NP) embedded thiol substituted MWCNTs, and magnetite doped Au NP embedded MWCNTs. Subsequently, effect of Au NPs on the electrodes in the selectivity and sensitivity of the sensor was studied. The aforementioned experiments suggest that the affinity of the arsenite ions towards the thiol groups were found to be magnified by the integration of an optimal amount of Au NPs. Further, addition of magnetite particles in the CNT matrix made the sensor more sensitive towards arsenic detection. The working principles, mainly the change of the surface potential, of the electrodes were characterized by surface potential microscopy (SPOM) study using atomic force microscopy (AFM). The study helped in the miniaturization of the arsenic sensor using screen printed commercial electrode system with a modification of the working electrode based on requirement as stated before. Interestingly, we extracted the electrochemical response using an open source Arduino UNO based potentiostat unit, as shown in Fig. 1, to translate the concept into a portable electrochemical arsenic sensor.
Keywords: Arsenite/Arsenate sensor, electrochemical, Screen printed electrode, Gold nanoparticle, Arduino UNO.

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Physics of Neutron-Gamma Sensors for Soil Elemental Analysis
Authors: Kavetskiy Aleksandr , Yakubova Galina , Sargsyan Nikolay , Prior Stephen A. , Torbert H. Allen , Chin Bryan A. 
Published: February 2020

Soil elemental (mainly carbon) analysis is one of the critical features in agricultural practice. The based on different physical principal methods are began applied today instead of traditional chemical analysis. One of such methods is neutron-gamma analysis. This method has a lot of advantage before traditional methods. It is nondestructive in situ method, no sample preparation is needed, no time consuming and labor-intensive method. Method is based on the registration of gamma rays response of the main soil nuclei at its irradiation by fast neutron flux.
In this report we will discussed physical principles of this method, namely processes of penetration, moderation and interaction with soil elements of fast neutrons, gamma rays appearing and propagation in soil, creating the gamma spectra in gamma detector. Based on this discussion the ways of soil elemental content determination from gamma spectra will be represented. The comparison of received results of neutron-gamma analysis with data of chemical analysis demonstrate that this method can replace this last in agricultural practice.
One-Step Covalent Immobilization of β-Cyclodextrin on sp2 Carbon Surfaces for Ultrasensitive and Selective Guest Detection
Authors: Li Zhi , Van Guyse Joachim F. R. , Retamero de la Rosa Victor , Van Gorp Hans , Walke Peter , Uji-i Hiroshi , Hoogenboom Richard , De Feyter Steven , Mertens Stijn F. L. 
Published: February 2020

The modification of solid surfaces with supramolecular hosts is a powerful method to tailor interfacial properties and confer chemical selectivity, but often involves multistep protocols that hinder facile upscaling. Here, we demonstrate the one-step covalent modification of highly oriented pyrolytic graphite (HOPG) with a β-cyclodextrin (β-CD) derivative, which efficiently forms inclusion complexes with hydrophobic guests of suitable size (e.g. ferrocene, dopamine). The modified β-CD-HOPG electrode discriminates analytes that form host-guest complexes with β-CD against a 100-fold higher background of electroactive substances that do not, even when these possess similar redox potentials. In addition, the enrichment of the analytes at the electrode surface, through complex formation with the β-CD units, leads to an enhanced electrochemical response and an improved detection limit (one order of magnitude for dopamine, compared to current cyclodextrin-based sensors).
The two unique features we demonstrate for the covalently grafted β-CD-HOPG electrode (selective sensing of hydrophobic analytes and ultrasensitive dopamine detection) do not come at the expense of ease of preparation: the one-step covalent modification can be completed in minutes, using standard electrochemical cells and equipment. Also, the procedure uses robust, commercially available HOPG substrates that can be reused by mechanical exfoliation many times, lowering the operational cost and further increasing wide accessibility and attractiveness of our approach.
The fundamental reasons for the high performance of the sensor may be related to its simple and well-defined structure, in which all the sensing units (covalently attached β-CD-moieties) are positioned uniformly and close to the collector surface (HOPG). This is achieved by the chemical characteristics of both reagent (a highly reactive, but sterically hindered diazonium compound, yielding monolayer modification exclusively) and substrate (low-reactive sp2 carbon surface, requiring highly reactive radical reagents for its modification), resulting in negligible side reactions despite the simplicity of the approach. These principles, and the resulting performance, can be taken as a proof of concept for entirely different sensors, e.g. using other van der Waals solids as substrates, but based on analogous chemistries.
Ethanol Gas Sensors Based on ZnO Nanotube Structures Fabricated By Atomic Layer Deposition
Authors: Lin Pengtao , Zhang Kai , Baumgart Helmut 
Published: February 2020

Among various Metal Oxide Semiconductor (MOS) gas sensors, ZnO nanostructure gas sensors have been widely used due to its large exciton binding energy, wide band gape of 3.37 eV, large exciton binding energy of 60 meV at room temperature, good electrical conductivity, low cost, and high mechanical stability. Furthermore, a variety of morphology has been developed to improve the properties and applications. In this work, ZnO nanotube nanostructures were fabricated as gas sensors to sense ethanol vapor due to its high electrochemical stability, nontoxicity, and, especially, high surface-to-volume ratio. Several coaxial ZnO nanotubes were synthesized on porous substrate to further enhance the sensing response to ethanol vapor with increased reaction surfaces in ZnO nanostructures.
In this study, ZnO nanotubes were synthesized by Atomic Layer Deposition (ALD) on Anodic Aluminum Oxide (AAO) templates with sacrificial Al2O3 layers. The second Al2O3 sacrificial layer followed by ZnO layer was synthesized on AAO samples by ALD with TMA (Al2(CH3)6) and DI water as precursors. In addition, the third ZnO thin film layer were deposited on the surface of the sacrificial layer of Al2O3 with precisely controlled thickness by ALD. The entire procedure outlined above for fabricating ZnO-Al2O3-ZnO structures is considered as one super cycle. More super cycles were applied to synthesize additional coaxial ZnO nanotubes. To eliminate the sacrificial layer, a Precision Ion Polishing System (PIPS) was used to remove the top cover as shown in Figure 1. Therefore, the Al2O3 sacrificial layers were exposed for Sodium Hydroxide (NaOH) wet etching. After the sacrificial layers were removed by NaOH, ZnO nanotube gas sensors were formed as shown in Figure 1 (b).
To investigate the sensing performance of ZnO nanotube gas sensors to ethanol vapors, a gas sensor testing system was developed with a sealed reaction chamber and a control system with stable temperature control and accurate gas concentration control. The sensing performance of the MOS gas sensors consisting of only core single crystal ZnO nanotubes, was compared to sensors consisting of double nested coaxial ZnO nanotubes, and further compared to three nested tube-in-tube coaxial ZnO nanotube structures and analyzed under various ethanol vapor concentrations at different temperatures. The ZnO nanostructures sensing results on ethanol vapor demonstrated the sensing performance was considerably enhanced due to the increased surface to volume ratio in the ZnO tube structures.

Figure 1
RF Sputtered Boron Carbon Nitride (BCN) Thin Films for Biological Applications
Authors: Nehate Shraddha Dhanraj , Saikumar Ashwin Kumar , Naga Varsha , Sundaram Kalpathy B. 
Published: February 2020

Boron carbon nitride (BCN) films have achieved attention owing to their crystal structure and unique properties. BCN compounds are expected to combine excellent properties of diamond, B4C and BN with their properties adjustable depending on their composition and structure[1]. B-C-N ternary compounds has been reported previously for biological applications [2-5].
In this study, we investigate RF sputter deposited BCN films for biological applications. Bacterial contamination in biomedical field has several adverse effects. BCN coating may interfere with bacterial adhesion and reduce bacteria colonization. BCN films are deposited by reactive sputtering of B4C target in presence of nitrogen. Bacteria colonies are grown on BCN thin films and incubated for 24 hours.
[1] A. Prakash, S. D. Nehate, and K. B. Sundaram, "Boron carbon nitride based metal-insulator-metal UV detectors for harsh environment applications," Optics letters, vol. 41, no. 18, pp. 4249-4252, 2016.
[2] W. Yang, P. Thordarson, J. J. Gooding, S. P. Ringer, and F. Braet, "Carbon nanotubes for biological and biomedical applications," Nanotechnology, vol. 18, no. 41, p. 412001, 2007.
[3] A. Bianco, K. Kostarelos, C. D. Partidos, and M. Prato, "Biomedical applications of functionalised carbon nanotubes," Chemical Communications, no. 5, pp. 571-577, 2005.
[4] S. H. Mir, V. K. Yadav, and J. K. Singh, "Boron–Carbon–Nitride Sheet as a Novel Surface for Biological Applications: Insights from Density Functional Theory," ACS Omega, vol. 4, no. 2, pp. 3732-3738, 2019.
[5] G. Ciofani, S. Danti, G. G. Genchi, B. Mazzolai, and V. Mattoli, "Boron nitride nanotubes: biocompatibility and potential spill‐over in nanomedicine," Small, vol. 9, no. 9‐10, pp. 1672-1685, 2013.
Hierarchical Nico Layered Double Hydroxidesnanosheets on Carbonized CNT/Cotton As a Highperformance Flexible Supercapacitor
Authors: Tianqi Hao , Wang Wei , Yu Dan 
Published: February 2020

Flexible electrodes, unlike the traditional ones, are highly integrated and portable, have attracted great attention in modern electronics fields. They can be served as essential parts in flexible supercapacitors and are critical items in the energy storage system for intelligent electronic products and health monitoring system. The core criteria to design a qualified flexible supercapacitor are high flexibility, stability and capacitance.
Cotton fabric is a good choice owing to the properties like low price, easily available and hydrophilicity, in which the hydroxyl groups make it favorable for adsorbing water and reacting with active materials. Carbon nanotubes (CNT) are widely used electrode materials with the merits of high specific surface area, good chemical stability, low resistance, thermal stability, high flexibility and excellent electrical properties. However, it is hard to obtain ideal properties only combining carbon nanotubes with cotton, because the low capacity of carbon nanomaterials.
Layered double hydroxides (LDHs) are promising Faradaic materials for the construction of high-performance supercapacitors, due to their unique two-dimensional lamellar structures and remarkable stability. Herein, hierarchical porous NiCo LDHs integrated with flexible CNT/cotton fabric current collector, are realized by a facile method, which exhibits a high capacitance. Moreover, the hybrid electrode has been assembled into a flexible supercapacitor device with the cycling stability of 94% capacitance retention after 3000 cycles.
The better flexibility and conductivity of the CNT, and highly intrinsic electrochemical activity of the NiCo LDHs as well as the superiority of the interwoven structure are responsible for the outstanding performance of the supercapacitor. The elaborate structural design can provide new insights into the construction of high-performance flexible supercapacitors.

Figure 1
Electrochemical Properties of Silver-Zinc Secondary Battery
Authors: Jeong Jiung , Lee Jong-Won , Shin Heon-Cheol 
Published: February 2020

The forthcoming green energy era strongly demands a next generation energy storage systems with much higher energy/power density, environmental friendliness, stability, etc. In relation to this, much effort has been made to explore the possible use of conventional primary battery in an electrically rechargeable form. Various alkaline batteries have been proposed as a candidate. Among this, silver-oxide battery draws a special attention because it has flat discharge voltage, high energy density (200 Wh/kg, 750 Wh/dm3) and superior rate performance. In addition, it is much safer and easier to recycle, as compared to lithium-ion batteries.
A silver-oxide battery is often called a silver-zinc battery when it is designed to be electrically rechargeable. Like its primary form, it is desirable to minimize the content of expensive silver, i.e., the design needs to be cathode-limited. Accordingly, the characteristics of silver-zinc battery might be strongly affected by the behavior of silver cathode. Based on the works on the silver anodization, it has been reported that silver is transformed to Ag2O and then AgO during anodic oxidation and the latter AgO formation needs relatively large driving force. In spite of many data on the anodization process of silver, however, there has been little information about the battery performance of silver-zinc secondary battery. Moreover, as far as we know, the systematic study on its electrochemical characteristics is extremely lacking.
The work provides an in-depth investigation of silver-zinc battery. In particular, the electrochemical properties and battery performance were systematically investigated at different charging/discharging rate, operating temperature, state of charge (SoC), etc. For this purpose, cathode-limited silver-zinc battery was fabricated using well-defined silver thin film and was analyzed by a variety of electrochemical techniques such as galvanostatic/potentiostatic methods, cyclic voltammetry, and impedance spectroscopy. From the combination of electrochemical, compositional, and structural analyses, the transformation of silver to Ag2O and AgO, and vice versa process was thoroughly investigated. For example, figure shows the SEM images and the corresponding XRD patterns of silver cathode at different SoCs. Porosity of products (Ag2O, AgO) gets increased with the SoC and the diffraction intensities of substrate and products are accordingly varied.
In this presentation, the charging/discharging mechanism of silver-zinc battery will be systematically explored and its uniqueness will be highlighted from the viewpoint of the kinetics of electrochemical reactions. Moreover, the cycling performance and the factors governing the capacity and efficiency degradation will be discussed.

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Mathematical Modeling of a Proton-Conducting Solid Oxide Electrolyzer Cell Using Computational Fluid Dynamics Simulation
Authors: Boyer Hailey , Shimpalee Sirivatch , Weidner John W. , Ma Zhiwen 
Published: February 2020

The proton-conducting solid oxide electrolyzer cell (H-SOEC) is a novel electrolysis technology, which operates in the intermediate temperature range (500-700°C), as opposed to the high temperature (800-1000°C) operating range of oxygen ion conducting solid oxide electrolysis cells (O-SOECs), or the low temperature (70-80°C) operating range of proton-exchange membrane (PEM) electrolyzers [1]. Proton-conducting electrolyte has high ionic conductivity in this intermediate temperature range, which is not exhibited in O-SOECs; this means that there are fewer material challenges for the development of these devices because they do not need to withstand temperatures up to 1000°C [1,2]. Additionally, this temperature ranges yields the benefits of improved thermodynamics at increased temperature, meaning they require less electrical energy input as compared to PEM electrolyzers [1]. H-SOECs are a promising technology because they retain the thermodynamic benefits of operation at high temperature, without the material complications seen in O-SOECs.
The purpose of this work is to model the 2D current density distribution of an H-SOEC at a applied electrolysis voltage. The model considers overpotential losses that occur due to kinetics of the electrochemical reaction, resistance in the cell components, and mass transport. The mathematical model uses electrochemical parameters fit with experimental data from [3] and is incorporated into the solving routine of computational fluid dynamics (CFD) software, Fluent. Figure 1 shows an example of the current density distribution in a planar H-SOEC cell that was obtained from the model simulation. Such parametric distribution is difficult to be measured, and the outcomes of this work would help the experimental development of this novel electrolyzer technology through optimization of operating conditions like temperature and gas feed compositions. The modeling approach also helps understand the thermal-flow management needs of this device as it is scaled up to the stack level. It will also provide a baseline understanding for more complex models that consider the internal transport phenomena in 3D, as only limited modeling papers on H-SOEC are available now.
References:

Bi et al., Chemical Society Reviews, 43 (24), (2014) 8255-8270.

Namwong et al., Journal of Power Sources, 331, (2016) 515-526.

Wu et al., Advanced Science, 1800360, (2018) 1-9.

Figure 1
Oxygen Reduction Reactions in Low-Viscosity Ionic Liquids Based on Phosphonium Cations
Authors: Higashi Toshikazu , Yamada Hirohisa , Sakguchi Yuki , Nomizu Daiki , Tsunashima Katsuhiko , Sakai Chikako , Katakura Katsumi 
Published: February 2020

There is high expectation for the lithium-oxygen (Li-O2) battery due to its high energy density because the cathodic active material is O2 in the air. The oxygen reduction reaction (ORR) at the cathode is of great importance, and it is strongly influenced by types of electrolytes. In particular, mass transport of oxygen molecules and its parameter, i. e. the solubility and the diffusion coefficient, are important for high performance of Li-O2 battery.
Ionic liquids (ILs) have drawn attentions as an electrolyte for Li-O2 battery, because of their unique properties like incombustibility, low vapor pressure, good ionic conductivity and wide electrochemical potential window [1]. Major ILs used for such electrochemical devices include imidazolium, pyridinium, quaternary ammonium, pyrrolidinium and piperidinium derivatives. On the other hand, phosphonium ILs have the remarkable features such as their chemical and thermal stabilities, and lower viscosity, compared to the ammonium counterparts [2]. Therefore, we focused on the phosphonium ILs. Recently, much lower viscosity was reported that based on small phosphonium cation such as triethylalkylphosphonium cation or tri-n-butylalkylphosphonium cation [2,3].

All electrochemical measurements such as cyclic voltammetry (CV) and potential-step chronoamperometry (CA) were performed using a three electrode type electrochemical cell at 25oC. A glassy carbon (GC) disk electrode (d = 1 mm) or a carbon fiber (CF) microdisk electrode (d = 33 μm) were used as the working electrode. Counter electrode and reference electrode were Pt wire and Ag+/Ag in 0.1 M Ag-OTf / EMI-TFSA , respectively.
CAs were performed on the CF microdisk electrode to estimate the solubility and the diffusion coefficient of oxygen in the ILs, individually, by the micro-electrode technique [4]. Two typical groups which consisted of triethylalkyl or tri-n-butylalkyl phosphonium cation were observed in the solubility correlated with molar volume. Moreover, two linear relationship between the diffusion coefficient and the viscosity of ILs were observed. In addition, the diffusion coefficients were correlated to occupied molar volumes which were calculated by the oxygen solubility in each IL. These result suggested that diffusion coefficient was not only affected the viscosity but also diffusion path originated from the cation structure.
[1] A. Khan, C. Zhao, ACS sustainable Chem. Eng.
4, 506 (2016)
[2] K. Tsunashima, M. Sugiya, Electrochem. Commun.
9, 2353 (2007)
[3] K. Tsunashima, M. Sugiya, Electrochemistry, (2007), in press.
[4] J. Maruyama, M. Inaba, T. Morita, Z. Ogumi, J. Electroanal. Chem.
504, 208 (2001)
Mathematical Modeling of Lithium Sulfur Batteries
Authors: Kamyab Niloofar , White Ralph E. , Weidner John W. 
Published: February 2020

Present day automotive battery packs typically consist of a large number of LIBs (few hundreds to thousands) to meet the required power and capacity needs of an EV. The high cost and limited mileage of present LIB-powered cars are due to the intrinsic limited capacities of the Li-ion insertion cathodes, which are nearing their practical limits and even a two-fold increase in energy density of current LIB cells is insufficient for the long-term demands of transport and electricity storage. Hence, for a wide deployment of EVs and maximizing electrification of the road transportation system, drastic improvements in today’s battery pack performance is needed.
Among new generation of lithium batteries, high theoretical energy density (~600 Wh/Kg) that may be 4-5 times higher compared to that of Li-ion batteries, good low-temperature performance, and abundance of inexpensive nontoxic raw material, make the lithium sulfur batteries (LSB) a promising candidate for major energy applications. However, there are several major issues facing rechargeable LSBs that impede their practical applications. In other words, challenges such as fast capacity loss, limited cycle life, high self-discharge rates, over-heating, and volume change of the cathode have hindered mass commercialization of these cells and limit their current application to UAVs and defense applications where the lightness and high energy is more important than life cycle.
Although a wide range of experimental researches have investigated novel strategies, material and designs for the cells, the mathematical and theoretical studies are scarce. Theoretical modeling plays crucial role in the exploration of the phenomena happening in the LiS cells. A mathematical model is presented to provides a better understanding of the complex multistep electrochemical reactions, side reactions, multiscale and multi component transport phenomena, phase change phenomena and precipitation reaction, and porosity and volume change of the cathode.