bluuebunny/crossref_metadata_2025 huggingface dataset:
Spontaneous Reduction of Eu(III) in LiCl-KCl Melt: Spectroscopic and Rde Studies
Authors: Bae Sang-Eun , Lee Nari , Kim Jong-Yun , Park Tae-Hong , Kim Jongwon
Published: February 2020

Pyrochemical process using molten salts has attracted much attention because of its potential to be applied to a future spent nuclear fuel management. In the pyrochemical process, electrochemical properties of lanthanide and actinide elements play a most important role in the recycling of the spent nuclear fuel. Therefore, it is important to know chemical and electrochemical behaviours of lanthanides and actinides in the molten salt for the successful developmentof the pyrochemical process. In this work, the spectro-electrochemical and rotating disk electrode (RDE) methods were employed to interrogate spontaneous reduction of Eu(III) ion, which is one of fission products, in LiCl-KCl eutectic at high temperature. By using the spectro-electrochemical system, the electrochemical potential of a working electrode can be controlled and, simultaneously, the evolution of the oxidation state of the Eu cation can be observed in the LiCl-KCl eutectic melt. RDE results can give information for electrochemical parameters such as diffusion coefficient, Tafel slope etc. as well as extent of the spontaneous reduction.

Fig. 1 shows UV-Vis absorption spectrum (a) and RDE results (b) of Eu(III) in LiCl-KCl melt. In the UV-Vis absorption spectrum, Eu(III) exhibits two broad and intense bands at 257 nm and 321 nm which are assigned f-d transitions of Eu(II).In the RDE results, oxidation current is also observed over +0.6 V. These results confirm that Eu(III) is spontaneously reduced to Eu(II) in LiCl-KCl. In this work, we performed UV-Vis absorption and RDE measurements of the Eu cations in LiCl-KCl at various temperature and evaluate how much Eu(III) is spontaneously reduced.

Fig. 1. UV-Vis absorption spectrum (a) and RDE results (b) of Eu(III) in LiCl-KCl melt.

Figure 1
Cu2o/Nanocarbon Architectures for Photoelectrochemical CO2 Conversion: Synthetic Aspects and Structure-Property Relationships
Authors: Endrodi Balazs , Kecsenovity Egon , Rajeshwar Krishnan , Janáky Csaba
Published: February 2020

Carbon nanomaterials, especially carbon nanotubes and graphene (either alone, or as building blocks of organized 3-D superstructures), are attracting significant attention as large surface area electrode support materials. Their composites with both inorganic and organic semiconductors represent an interesting class of new functional materials. In the first part of my talk I will briefly focus on the use of electrosynthetic (and photoelectrosynthetic) methods for preparing semiconductors on nanocarbon-modified electrode surfaces.1,2I will show how electrodeposition can be used to tune composition, crystal structure, and morphology of the nanocomposites for targeted applications.

In the second part of my talk, selected examples will be given for how these electrosynthesized hybrid assemblies can be deployed in photoelectrochemical CO2 conversion. Given that CO2 is a greenhouse gas, using sunlight to convert CO2 to transportation fuel (such as methanol) represents a value-added approach to the simultaneous generation of alternative fuels and environmental remediation of carbon emissions from the continued use of conventional fuels.3 I will present the controlled synthesis and photoelectrochemical behavior of Cu2O/CNT4 and Cu2O/3D graphene composites for the CO2 reduction application. A carefully designed, multiple-step electrodeposition protocol was developed that ensured homogeneous coating of the CNTs with the Cu2O nanocrystals. This enhanced charge transport property for the hybrids resulted in a drastic increase in the photocurrents measured for the CO2 reduction. In addition to this superior performance, long term photoelectrolysis measurements proved that the Cu2O/CNT hybrids were more stable than the oxide alone. Structure property relationships will be shown, which may act as guidelines for the rational design of nanocomposite photoelectrodes.

Figure 1. Illustration of the structure of the Cu2O/CNT composite and the increasing photocurrent with the increasing CNT-content.

[1] C. Janáky and K. Rajeshwar: The Role of (Photo)electrochemistry in the Rational Design of Hybrid Conducting Polymer / Semiconductor Assemblies: From Fundamental Concepts to Practical Applications, Prog Pol Sci, 43 (2015) 396-435

[2] C. Janáky, E. Kecsenovity, K. Rajeshwar: Electrodeposition of Inorganic Oxide/ Nanocarbon Composites: Opportunities and Challenges, ChemElectroChem, 3 (2016) 181-192

[3] G. Ghadimkhani, N. R. De Tacconi, W. Chanmanee, C. Janaky, K. Rajeshwar: Efficient solar photoelectrosynthesis of methanol from carbon dioxide using hybrid CuO/Cu2O semiconductor nanorod arrays, Chem. Commun. 49 (2013) 1297–1299

[4] E. Kecsenovity, B. Endrődi, Z. Pápa, K. Hernádi, K. Rajeshwar, C. Janáky: Decoration of ultralong carbon nanotubes with Cu2O nanocrystals: a hybrid platform for enhanced photoelectrochemical CO2 reduction, J Mater Chem A, 4 (2016) 3139-3147

Figure 1
(Keynote) One-Electron Initiated Two-Electron Oxidation of Water Catalyzed By Aluminum Porphyrins, Incorporating Earth
Authors: Kuttassery Fazalurahman , Mathew Siby , Yamamoto Daisuke , Onuki Satomi , Nabetani Yu , Tachibana Hiroshi , Inoue Haruo
Published: February 2020

One of the most promising solutions to the current global problems of energy and the environment would be to develop a clean system for the chemical conversion of solar energy, for example, photochemical hydrogen evolution and carbon dioxide fixation. In both cases, the water molecule should be the electron source, as is the case with natural photosynthesis. The point of research in this area is to discover how the electrons of water can best be utilized. The oxidation of water can be approached through (a) one-electron (b) two-electron and (c) four-electron processes. In spite of remarkable progress of molecular catalysts, the visible light-induced oxidation of water to molecular oxygen via the four-electron process has been one of the bottle-necks in the field, mostly due to the photon-flux density problem of sunlight, with its intrinsically limited intensity. A photochemical method for the four-electron oxidation of water requires four photons to excite sensitizers and catalysts in a stepwise manner in order to reach the higher oxidized states. Under typical sunlight conditions, the time interval between the arrivals of photons to a single molecule is on the order of seconds, which is far longer than the usual timescale for the survival of the highly unstable oxidized states needed to elicit the catalytic activity. Alternative approaches thus are clearly required. In this context, we have been studying the one-electron initiated two-electron oxidation of water. The latest results on the oxidation of water catalyzed by earth-abundant metalloporphyrins will be reported.
(Invited) Observing Photochemical Charge Transport at Particle Based Tandem Junctions for Overall Water Splitting
Authors: Osterloh Frank E. , De Melo Mauricio Alves , Yang Yuxin , Wang Jiarui
Published: February 2020

Photochemical charge generation, separation, and transport across particle interfaces are central to photoelectrochemical water splitting, a pathway to hydrogen from solar energy. Here we use surface photovoltage spectroscopy (SPS) to probe these processes in films of BiVO4 and Rh:SrTiO3 particles on fluorine doped tin oxide (FTO) or p-doped silicon wafers. Particle films were made by drop-coating of premade particle suspensions in water followed by thermal annealing. Photochemical charge separation in the films was measured as a function of layer thickness and illumination intensity, and in the presence of sacrificial electron donors. The formation of Tandem junctions is clearly observed and to result in a maximum photovoltage of up to -150 mV under 0.3 mW cm-2 illumination. Charge separation is limited by light absorption and by slow electron transport. Overall Water Splitting with visible light an a quantum efficiency of 0.61% at 400 nm was observed with a direct contract tandem photocatalysts made of ruthenium-loaded Rh:SrTiO3 nanocrystals and of BiVO4 microcrystals. The activity and stability of this system depends on the temperature employed for generating the tandem junction. The ability to measure the built-in potential in particle junctions promotes the development of particle-based systems for artificial photosynthesis.

Figure 1
Magnesium Insertion into the Chevrel Phase Mo6S8: XPS Analysis
Authors: Richard Julien , Colin Jean François , Benayad Anass , Martinet Sebastien
Published: February 2020

Since the earlier works in 2000 by Aurbach et al
1, magnesium-ion batteries emerged as an alternative to lithium-ion batteries thanks to many advantages: magnesium is the 5th most abundant metal in the earth crust, its divalent character and its ionic radius similar to lithium ionic radius gives it a volumetric capacity higher than lithium (3833 Ah/L and 2046 Ah/L respectively). Eventually the absence of dendritic growth on metallic magnesium is a plus in term of security. Several cathode materials were proposed for Mg-ions battery, nevertheless the reference positive electrode material in Mg-Ion technology remained the Chevrel Phase with the formula Mo6S8. The Chevrel phase, synthesized by R. Chevrel et al
2 in 1974, was described as an octahedral cluster of molybdenum located in a cube of sulfur that forms a Mo6S8 pattern. Structural analysis3 (X-Ray Diffraction) showed the existence of 12 insertions sites localized inside a cube of sulfur surrounded by Mo6S8clusters as illustrated in Fig. 1.

The electrochemistry highlighted 2 types of insertion sites able to host Mg2+at different potentials.

Being considered as the reference cathode material for Mg-ion systems, it has been extensively studied, especially on the structural and electrochemical point of view. However, the precise red-ox processes taking place during Mg insertion-deinsertion remain unclear.

In this study X-ray Photoemission Spectroscopy (XPS) has been used to get a direct observation of the redox mecanism during charge/discharge of the material. We performed ex-situ XPS core peak analyses on Mo6S8electrodes at different states of charge to probe the molybdenum and sulfur oxydation state and the environment (polarized or metallic) of inserted magnesium ions. These results were discussed based on a step-by-step XRD and XPS study before and after cycling, and correlated with the electrochemical performance of Chevrel phase. Fig 2 illustrates Mo 3d and Mg 2p orbitals in Mg1.72Mo6S8. In one side we can see the evolution of molybdenum oxidation states during discharge and on the other side the two environments of inserted magnesium is underlined.

References :

(1) D. Aurbach, Z. Lu, A. Schechter, Y. Gofer, H. Gizbar, R. Turgeman, Y. Cohen, M. Moshkovich & E. Levi,
Nature vol 407 (2000) 724

(2) R. Chevrel et al, Mat. Res.
BuLl. Vol. 9, pp. 1487-1498, 1974M. D. Levi, E. Lancry, H. Gizbar, Z. Lu, E.

(3) R. Chevrel, M. Sergent Superconductivity in Ternary Compounds I
Volume 32 of the series Topics in Current Physics pp 25-86

Figure 1
(Invited) High-Capacity Lithium-Sulfur Batteries at Low Electrolyte/Sulfur Ratios
Authors: Wang Donghai , Chen Shuru
Published: February 2020

Lithium-sulfur ((Li-S) batteries have a high theoretical specific energy of 2600Wh/kg, which makes it promising as a next generation electrochemical energy storage system. Li-S system operates by electrochemical conversion of sulfur through a multi-step redox reaction, forming different lithium sulfide products. The formation of soluble polysulfide and insoluble, insulating Li2S contributes to poor sulfur utilization and cycling efficiency, and capacity fading. As one important component in Li-S batteries, the electrolyte plays a key role in the electrochemical performance of lithium-sulfur batteries. The excess of electrolyte is still required for adequate Li-S cell performance and resultant drawdown in the energy density. The presentation will discuss development of Li-S batteries with emphases on applications of new functional electrolyte which enables an alternate electrochemical reaction pathway for sulfur cathodes by the formation of dimethyl polysulfides and lithium organosulfides as intermediates and reduction products.1 This new pathway not only provides high capacity but also enables excellent capacity retention. Furthermore, we demonstrate a stable capacity of around 1000 mAh g-1 at a low electrolyte/sulfur ratio of 5 mL g-1 using high-sulfur-loading (4 mg cm-2) cathodes, which almost doubles the capacity obtained with conventional electrolytes under the same conditions. These results highlight the practical potential of this electrolyte system to enable high-energy-density Li-S batteries.
Electro Chemical Properties of Hard Carbon Single Particles for Anode in Sodium Ion Batteries
Authors: Lim SeongHyeon , Yamada Yuto , Kim Sung-soo , Kanamura Kiyoshi
Published: February 2020

Nowadays, Interest of lithium-ion batteries have been increasing for use many electronic equipment and electronic vehicles. But Lithium resources are unevenly distributed. Especially, mainly in South America, and the materials cost was steeply increased during the first decade of this century due to increasing global demand for lithium-ion accumulators.

Sodium is the second-lightest and smallest alkali metal next to lithium and their electrochemical equivalent and standard potential are very similar to lithium. So, sodium based energy storage is of great interest to realize lithium-free high energy and high voltage batteries. Hard carbon had been utilized as a negative electrode in the first commercial Li-ion battery, and the hard-carbon electrodes deliver comparable reversible capacity without a staging transition due to the structural disorder.

In this study, we were investigated the electrochemical properties of a single particle of hard carbon (10m in diameter, provided by Aekyung Co.) using a microelectrode technique. A finely manipulated Cu-coated gold micro electrode (diameter:20m) was used to maintain electrical contact with a hard carbon single particle in the 1M NaPF6 (EC:PC=1:1) electrolyte under optical microscope and the galvanostatic charge-discharge tests carried out. This single particle technique using microelectrode gives material’s intrinsic information, without mixed effect with parameters of electrode such as compositions (binder and conductive agent), density (porosity) and loading amounts on the unit area.
A Rotating Ring Disk Electrode Study of the Stability in Different Electrolytes for Lithium-Oxygen Batteries
Authors: Chen Jenn-Shing , Cheng Meng-Huan
Published: February 2020

The electrolyte formula (especially, the composition of organic solvent) is well-known to influence the electrochemical performance of Li-O2 batteries. The electrolyte instability in the battery can be attributed to its reaction with the superoxide radical (O2
•
−) produced at the battery’s cathode during discharge. In this work, we have employed the rotating ring disk electrode (RRDE) technique to study the stability of various organic solvents against O2
•
− by the quantification of the electrolyte decomposition rate constant (k) for the reaction between various electrolytes and O2
•
−. Moreover, RRDE transients are also applied to estimate O2 solubility and diffusion rates of O2 and O2
•
− coefficients ( and ) at different electrolytes.
ZnO Nanostructured Wires for Gas Sensing Applications
Authors: Abidov Amir , Abdukarimova Sevara , Ziyamukhamedova Umida , Babu Eadi Sunil , Jeong Soon-Wook , Kim Sungjin
Published: February 2020

ZnO wires were fabricated using microwave evaporation method. Microstructure investigations by Scanning Electron Microscopy showed that wires consist of ZnO nanostructures which are interconnected. The crystallinity of nanostructures was characterized using X-ray diffractometry. It was found that ZnO nanostructures had mostly wurtzite structure. Uv-visible spectroscopy revealed  absorbance up 380nm. Prepared samples were utilized in gas sensors. It was found that highly porous ZnO nanostructured wires have high sensitivity to natural gas. Results were discussed.
High Surface Area 3D Hierarchical Ni(OH)2-Coated Ni Microflowers for Non-Enzymatic Glucose Sensor with High Sensitivity and Low Detection Limit
Authors: Manikandan Arumugam , Lee Ling , Medina Henry , Chen Chia-Wei , Wang Zhiming , Chueh Yu-Lun
Published: February 2020

Glucose detection has attracted considerable interest in diagnosis and management of diabetes mellitus as well as monitoring and controlling the food processing. However, the development of sensitive and accurate glucose sensors with an ultralow detection limit is imperative to prevent type- II diabetes. In this work, the enzyme-free glucose sensor based on high surface area three dimensional (3D) hierarchical Ni microflowers with a Ni(OH)2 coating layer has been demonstrated in a simply single step by a simple single chemical reaction at a low temperature of 80 oC. In addition, our devices exhibit an outstanding detection limit as low as 2.4 nM with a high sensitivity of 2392 µA mM−1cm−2 compared to all Ni based modified electrodes, which is attributed to not only the increased surface area due to the controlled formation of spikes but also the contribution of Ni(OH)2 coating layer.
A Universal Strategy for Aptamer-Based Nanopore Sensing Throughhost-Guest Interactions inside a-Hemolysin
Authors: Li Ting
Published: February 2020

Nanopore emerged as a powerful single-molecule technique over the past two decades, and has shown applications in the stochastic sensing and biophysical studies of individual molecules. Here, we report a versatile strategy for nanopore sensing by employing the combination of aptamers and host–guest interactions. An aptamer is first hybridized with a DNA probe which is modified with a ferrocene_cucurbit[7]uril complex. The presence of analytes causes the aptamer– probe duplex to unwind and release the DNA probe which can quantitatively produce signature current events when translocated through an a-hemolysin nanopore. The integrated use of magnetic beads can further lower the detection limit by approximately two to three orders of magnitude. Because aptamers have shown robust binding affinities with a wide variety of target molecules, our proposed strategy should be universally applicable for sensing different types of analytes with nanopore sensors.
Investigation of the Hybrid Catalytic System GC/Conducting Polymer/CdS/Enzyme for the Detection of Phenolic Compounds.
Authors: Widera Justyna , Chaykina Diana , King Sophia , Osial Magdalena E , Jackowska Krystyna
Published: February 2020

Phenol and its derivatives such as: chlorophenols, catechols are released into waterways by industries. Some of these phenolic compounds pose a serious life threat. The detection of phenolic compounds could therefore lead to mitigation of their harmful effects. [1,2] Many researchers studied conductive polymers [1,2] for this purpose. It was seen that the modification of the electrode surface with the polymer and the enzyme catalysed the oxidation reactions of catechol. [3,4]

In this project, a further modification of conducting polymer/enzyme system was made by adding a small amount of semiconducting CdS nanoparticles. The aim of this was to check if under illumination, photoactive CdS can improve the range of detection of catechol and if under illumination the enzyme still has catalytic properties.

The hybrid system consisting of disc electrode (Pt or GC) modified with conducting polymer polyindole (PIN) or polyindole 5-carboxylic acid (PIN-5-COOH), cadmium sulphide CdS nanoparticles and enzyme (Tyrosinase) were examined for detection of catechol. All individual parts as well as the overall hybrid assembly was characterized electrochemically and in the case of CdS addition photoelectrochemically to examine the role of each part of the hybrid in the redox reaction of catechol. Additionally, Pt|CdS, Pt|PIN, Pt/PIN-5-COOH, Pt|PIN|CdS and Pt|PIN-5-COOH|CdS hybrids were also imaged using SEM.

Better catalytic activity was observed for the GC/PIN 5-COOH/CdS hybrid than Pt/PIN/CdS system, so further studies were focused on the former system. Poly(indole-5-carboxylic acid) functions as a conductive polymer while also providing a functional group onto which an enzyme, such as Tyrosinase (TYR), can be attached covalently. The enzyme did not lose the catalytic activity while being illuminated with a Xenon lamp. It was found that the addition of CdS nanoparticles to the GC|PIN-5-COOH|TYR system produces under illumination slightly smaller but more stable currents, which causes the variation of the catechol quantitation limits: a) GC|PIN-5-COOH|TYR electrode (2.5μM to 0.13mM) and b) GC|PIN-5-COOH|CdS|TYR electrode (2.5μM to 0.34mM).

The enzyme kinetics parameters were calculated using Lineweaver-Burk plot for the tyrosinase immobilised on the polymer surface. As hypothesised, the presence of CdS had an effect on the overall hybrid GC|PIN-5-COOH|CdS|TYR system under illumination, reducing the value of Km by ~50% when illuminated as compared to dark, suggesting more efficient enzyme behaviour.

U. Lange, N.V. Roznyatovskaya, and V.M. Mirsky, Anal. Chim. Acta
614, 1-26 (2008).

K. Jackowska and P. Krysiński, Anal. Bioanal. Chem.
405, 3753-3771 (2013).

A.T. Biegunski, A. Michota, J. Bukowska, and K. Jackowska, Bioelectrochemistry
69, 41-48 (2006).

J. Maciejewska, K. Pisarek, I. Bartosiewicz, P. Krysiński, K. Jackowska, and A.T. Biegunski Electrochim. Acta.
56, 3700-3706 (2011).
Anionic-Exchange Ionomer-Films for Electrocatalytic Applications
Authors: Bertoncello Paolo , Jones Thomas Ross , Aldave Hernandez Sandra , Kaspar Robert , Letterio Michael , Yan Yushan
Published: February 2020

The electrochemical characterisation of recasted films of a highly conductive quaternary phosphonium-based ionomer (TPQPCl) is reported for the first time. TPQPCl was synthesised using the procedure developed by Yan [1]. Films of TPQPCl were deposited on electrodes (GCE, ITO) usind drop casting methods. The thickness of dropcasted films was calculated in dry state using profilometer. TPQPCl-films were characterised using cyclic voltammetry (CV) and chronoamperometry (CA) in the presence of anionic redox mediaotrs such as the couple Fe(CN)6
4-/3-, and IrCl6
2-/3- probes. CVs showed the effectiveness of the ionomer films in preconcentrating anionic redox mediators. CVs also demonstrated the permselectivity of such films by repelling positively charged redox mediators, such as the [Ru(bpy)3]2+/3+ and [Ru(NH3)6]2+/3+ redox couples. CV and CA were used to estimate the surface coverage, the concentration of the electroactive species, and the apparent diffusion coefficient and to elucidate the effect of polymer concentration on the charge transport properties within the polymer films. To explore potential electrocatalytic applications, the TPQPCl-films were tested towards detection of anionic analytes in food such ascorbic acid and sulphites. TPQPCl films were also used as polymeric template to incorporate anionic salts of noble metals (Pt, Pd) to form Pt and Pd nanoparticles by reduction with NaBH4 for catalytic applications for hydrogen oxidation (HOR) and oxygen reduction (ORR) reactions.

References

[1] S. Gu, R. Cai, T. Luo, Z. Chen, M. Sun, Y. Liu, G. He, Y. Yan, Angew. Chem. Int. Ed., 48, (2009), pp. 1-5

Figure 1
Streptavidin-Functionalized Nitrogen Doped Graphene Platform for Sensitive Electrochemical Immunoassay of Tumor Marker
Authors: Yang Zhanjun , Lan Qingchun
Published: February 2020

Tumor markers are biomacromolecules existing in blood or tissue, which are associated with cancer and whose measurement is useful in clinical diagnosis. The electrochemical immunoassay has attracted extensive attention due to its specific advantages such as high sensitivity, low cost, and easy handling. Here, a novel and highly efficient streptavidin-functionalized nitrogen doped graphene platform was proposed for sensitive electrochemical immunoassay of tumor marker. The biofunctionalized-nitrogen doped graphene platform shows large reactive surface area and excellent biocompatibility. The capture antibody can be efficiently immobilized on the biosensing platform surface based on the highly selective recognition of streptavidin to biotinylated antibody. Using carcinoembryonic antigen (CEA) as model analyte, the highly efficient electrochemical immunosensing shows a linear range from 0.02 to 12 ng/mL with a correlation coefficient of 0.9980. The limit of detection was calculated to be 0.01 ng/mL (S/N=3). This biofunctionalized-nitrogen doped graphene platform shows much better performance compared with the platform without nitrogen doped graphene (shown in Fig. 1). This work provides a promising application in the determination of various tumor markers.

References:

[1] N. Zamcheck, E. W. Martin, Cancer
2006, 47, 1620.

[2] Y. Wan, Y. Su, X. Zhu, G. Liu, C. Fan, Biosens.
Bioelectron.
2013, 47, 1.

[3] L. H. Tang, Y. Wang, Y. M. Li, H. B. Feng, J. Lu, J. H. Li, Adv. Funct. Mater. 2009, 19, 2782.

[4] J. Wang, G. Liu, M. H. Engelhard, Y. Lin, Anal.
Chem.
2006, 78, 6974.

[5] G. Lai, J. Wu, C. Leng, H. Ju, F. Yan, Biosens.
Bioelectron. 2011, 26, 3782.

[6] C. Ou, R. Yuan, Y. Chai, M. Tang, R. Chai, X. He, Anal.
Chim. Acta
2007, 603, 205.

Figure 1
Development of Novel Immunosenser System for Sex Determination of Fish
Authors: Sakurai Taro , Wu Haiyun , Yoshizaki Goro , Ohnuki Hitoshi , Endo Hideaki
Published: February 2020

Aquaculture development of some important farmed fish, which have great economic and cultural importance, is key due to the decline of wild populations. While in captivity, fry production relies on the spontaneous formation of male and female pairs. Sex determination of these types of fish is not possible based on morphologic criteria, however, and it is very difficult to optimize reproduction conditions and fry production in each pond, which seriously hampers the culture of this species. Therefore, we developed sexing methodologies based on the determination of 11-ketotestosterone (11-kt) levels as an important androgenic sex hormone in immature juveniles. Detection methods such as the enzyme-linked immunosorbent assay, are too time consuming and complex for their practical application in the aquaculture setting. Thus, a simple and rapid method of detecting 11-kt for early determination of fish sex is desired. Here we describe a label-free immunosensor system that detects 11-kt levels in fish with high sensitivity.

Detection of 11-kt using cyclic voltammetry is achieved by immobilizing both anti-rabbit IgG antibody (high efficiency and recovery rate binding anti-11-kt antibody) and anti-11-kt antibody (selective detection of 11-kt) on an Au electrode (diameter: 3 mm) with a self-assembled monolayer. The principle of the system is based on the maximum oxidation peak current change induced by the generation of a nonconductive antigen-antibody complex, which depends on the levels of 11-kt in the sample. The effects of temperature and pH on the CV oxidation peak current change were tested. We found that the highest current reduction (optimal immune response conditions) occurred at pH 7.5 and 25℃. The immunosensor showed a response to 11-kt levels, and the oxidation peak current linearly decreased in the range of 0.125 - 0.750 ng ml-1 (R=0.9871) as shown in Figure. A good correlation between the 11-kt concentration and sensor current change was found and it only takes about 10 min for electrochemical measurement of one sample. The specificity of the label-free immunosensor system was investigated using other steroid hormones, such as testosterone. The specific detection of 11-kt was suggested by a minimal change from -1.1 to 0.8 % in the anodic peak value of the other steroid hormones. These findings suggest that the proposed label-free immunosensor could be useful for rapid and convenient analysis of 11-kt levels in fish.

Figure 1
Preparation and Electrochemical Properties of Semi-Perfluoroalkyl Compounds in a Li-Ion Electrolyte Solution
Authors: Shimada Daiki , Ando Yuuki , Morita Yuki , Okamoto Hiroaki
Published: February 2020

Introduction

Organogels formed by a low moleculr weight organic gelators (LMOG) are of great attentions for their application to organic gel electrolytes of lithium ion battery, dye-sensitized solar cells and so on [1]. Several studies on organogel electrolytes based on LMOGs show that the conductivity is practically identical in the gel and in the corresponding solution [2].

In our previous papers, LMOG having perfluoroalkyl groups in the molecules can gelate aprotic polar solvents such as PC, GBL and so on [3].

Here we report preparation and electrochemical properties of semi-perfluoroalkylated compounds 1 and 2.

Experimental

Cyclic voltammmetry was carried out in a potential range of 0-3 V at a rate of 1.0 mV s–1, where natural spheroidal graphite purchased from Hosen Co. Ltd. was used as a carbon anode, and lithium metal was used as a counter and reference electrode. The oxidation potential measurements using linear sweep voltammmetry was carried out in a potential range of 3-7 V at a rate of 1.0 mV s–1, where a platinum was used as a working electrode. The electrolyte solution was a 1M LiPF6/ethylene carbonate and ethyl methyl carbonate (EC:EMC=1:2).

Results and discussion

For compound 1, in the first sweep of the untreated carbonaceous thin-film electrode, irreversible cathodic currents were observed at ca. 0.5 V. The peak significantly reduced after the second cycle and therefore should be attributed to irreversible reactions such as electrolyte decomposition followed by formation of a surface film [4]. The CVs results indicate that the presence of compound 1 in the electrolyte solution is similar to the solution on cycling behavior.

The oxidation potential of compound 1 is in accordance with that of the EC-EMC electrolyte without additive, expressing high resistance properties against oxidative decomposition.

In this presentation, the electrochemical properties of the other compounds having a semi-perfluoroalkyl unit in the molecules will be discussed in terms of the molecular structeres.

Reference

[1] M. Miura et al ., ECS Transactions, 50, 89-94 (2013). L. Tao, et al., J. Mater. Chem. A, 3, 2344-2352 (2015).

[2] A. Iuchi, et al., ECS Transactions, 16(24), 65-70 (2009). T. Yoshida, et al., ECS Transactions, 50, 95-102 (2013).

[3] t. yoshida, et al., Chem. Lett., 44 (4), 512-514 (2015), T. Yoshida, et al., Bull. Chem. Soc. Jpn, 88, 1447-1452 (2015).

[4] T. Doi, et al., J. Phys. Chem., 116, 12422 (2012)

Figure 1
CVD Grown Mwcnts and Graphene for Pemfcs Application
Authors: Ion-Ebrasu Daniela , Enache Stanica , Bubulinca Constantin , Carcadea Elena , Varlam Mihai , Stefanescu Ioan , Wittstock Gunther
Published: February 2020

In this paper we report the development of Multi-Walled Carbon Nanotubes (MWCNTs) and graphene via chemical vapor deposition (CVD) for PEM Fuel Cells applications. MWCNTs growth are achieved by the flow of ethylene and hydrogen gasses over iron beased catalytic substrates at different temperatures and gas flow. Graphene growth is carried out by the flow of methane and hydrogen gasses over various thickness cupper substrates cleaned by different methods (electropolishing, acetone and acetic acid) at low (500 mTorr) and atmospheric pressure. Characterization is performed with XRD, optical microscopy (SEM/EDS) and Raman/AFM spectroscopy. Results show noticeable differences in Raman signals and optical color contrast regarding the preferential growth of MWCNTs, and between the number and quality of layers of graphene and graphite, as well as distinctions between single-to-few- and multi-layer graphene, respectively. The electrochemical behavior of CVD grown MWCNTs and graphene are studied by cycling voltammetry on rotating disk electrode (RDE) to determine the activity of toward oxygen reduction reaction (ORR). Scanning Electrochemical Microscopy (SECM) is used to shows the localized electrochemical behavior difference between the MWCNTs and graphenes.
Hydrogen Entry Behavior into Pre-Rusted Steel in an Atmospheric Corrosion Environment
Authors: Kaneko Saya , Tada Eiji , Nishikata Atsushi
Published: February 2020

Introduction

In recent years, high-strength steels have been widely used in many engineering fields such as automobiles and construction. However hydrogen embrittlement has been a great concern because the susceptibility of the steels to hydrogen embrittlement is highly relevant with the strength of the steels. Especially, since high-strength steels are often used in atmospheric corrosion environments, hydrogen atoms generated by corrosion reaction can cause of hydrogen embrittlement. In addition, hydrogen absorption behavior would depend on the formation of rusts on steel. Therefore, it is needed to clarify hydrogen absorption mechanism into rusted steels in atmospheric corrosion environments. In this study, effect of rusts on hydrogen entry behavior of steels in an atmospheric corrosion environment is discussed based on the results of hydrogen permeation current and corrosion potential.

Experimental

In this study, in order to investigate the effect of rusts on the hydrogen entry behavior into steel, hydrogen permeation current for pre-rusted steel was measured by Devanathan-Stachurski method1. A sheet of plain carbon steel (0.018%C, 0.01%Si, 0.18%Mn, 0.017%P, 0.007%S, bal. Fe) was used as a material. The sheet was cut into a small coupon of 25 mmw x 35 mml x 0.7 mmt. The steel surface for a hydrogen-withdrawal side was electroplated with Pd ca. 400 nm in thickness. The other surface was rusted by applying a 30 μL of 100 mM NaCl droplet on its surface and exposed to wet-dry corrosion cycles. During the wet-dry corrosion cycles, relative humidity was changed repeatedly from 40 % to 95 % at a constant rate of 22.5 %/h and 25 oC. A 30 μL of Milli-Q water (18 Mω•cm) was placed on the pre-rusted steels to measure hydrogen permeation current. During drying of the water droplet, corrosion potential for the pre-rusted steel was measured with a Kelvin probe simultaneously with hydrogen permeation current.

Results and Discussion

Fig. 1 shows changes of corrosion potential and hydrogen permeation current for pre-rusted steels during drying of a water droplet. The water droplet was placed on the pre-rusted steel at 0 min in Fig. 1. As shown in Fig. 1, corrosion potential for the pre-rusted steel exposed to 3 wet-dry cycles keeps almost constant of ca. -0.7 V vs. SSE during the drying of the droplet and the evolution of hydrogen permeation current can be slightly observed. By contrast, in the case of 30 wet-dry cycles, corrosion potential is less noble and hydrogen permeation current becomes larger compared with the case of 3 wet-dry cycles. These results suggest that hydrogen entry behavior of the pre-rusted steels is related to the characteristics of the rusts after the exposure to the wet-dry corrosion cycles.

Reference

M. A.V. Devanathan, A. Stachurski, Proc. Roy. Soc., A270, 910(1962).

Figure 1
Surface Analysis of 4-Methyl-2-Phenyl-Imidazole on the Cu Surface
Authors: Finsgar Matjaz
Published: February 2020

Corrosion problems represent a large portion of the total costs in diverse industrial fields for companies every year worldwide. Moreover, appropriate corrosion control can help avoid many potential disasters that can cause serious issues including loss of life, negative social impacts, and water resource and environmental pollution. It is almost impossible to prevent corrosion, however it is possible to control it. Commonly, organic compounds are used as corrosion inhibitors.

The studied compound herein, MePhI, is presented for the first time to protect any metallic material against corrosion. This compound effectively protects copper from corrosion in a highly corrosive chloride solution even after 0.5 year of immersion. To study this system X-ray photoelectron spectroscopy was employed.

Using the Tougaard method a surface layer thickness of the MePhI was determined to be 0.3-0.5 nm by analyzing the background of the XPS survey spectrum. Moreover, orientation and the manner of bonding of MePhI on the Cu surface is explained especially by examining the XPS-excited Auger Cu L3M4,5M4,5 spectra, which is a “fingerprint”  of a Cu(I)-MePhI connection. Angle-resolved XPS measurements suggest that both the C and N atoms of the MePhI molecule are involved in the inhibitor surface bonding. Finally, it is also suggested that MePhI molecules are lying flat on the surface.
Formation of Nanotubular Oxide Layers on Ti Alloys Containing Noble Metal
Authors: Otani Yuki , Tsuchiya Hiroaki , Fujimoto Shinji
Published: February 2020

Self-organized porous oxides have attracted attentions as functional materials for photocatalyst, water splitting, photo anode of dye-sensitized solar cells and storage capacitors due to their properties and unique structures. Formation of highly ordered porous oxide layers on various valve metals (Al, Ti, Ta, Hf, Zr, Nb or W) and their alloys by electrochemical anodization have been reported. Especially, TiO2 nanotubes have been studied as functional electrodes and the formation of TiO2 nanotubes has been widely investigated in fluoride containing electrolytes. However, TiO2 has low conductivity and relatively large band gap. TiO2 nanotubes are decorated with other elements to enhance their photocatalytic properties by sputter deposition, photodeposition and annealing under doping gas. In order to improve the properties further, the optimization of process is required. Recently, it has been reported that anodization of a Ti alloy results in the formation of nanotubular oxide layer decorated with the alloying element which exhibits better properties compared to bare TiO2 nanotubular layers.

The purpose of present work is to examine the formation of nanotubular oxide layer on Ti alloys containing noble metal by electrochemical anodization and to study the effect of alloy compositions and electrochemical conditions on the structures and properties.
Batteries: Today’s Advances and Future Challenges
Authors: Tarascon Jean Marie
Published: February 2020

Research’s progresses in rechargeable batteries are driven by ever increasing demands for portable electronic devices as well as for powering electric vehicles and providing load-leveling for mass storage of renewable energy. This will ever increase over years to come with new business players challenging today’s traditions. Whatever, Li-ion batteries are the systems of choice for the aforementioned applications with several contenders’ technologies being presently developed. In our journey into the future we will first highlight ongoing research strategies pertaining to these various systems together with the remaining challenges prior to enter into a personal prospective mode in which new trends and new ideas, which require much collaborative and integrated work, to become a reality will be shared.
Market Trend of Batteries in Consumer, Automotive, and Grid
Authors: Pillot Christophe
Published: February 2020

The Battery market worldwide in 2015

The Lithium ion value Chain

Consumer, automotive and Stationary market forecasts (2025)
“Water-in-Salt” Electrolyte Enabled High Voltage Aqueous Li-ion Chemistries
Authors: Suo Liumin , Borodin Oleg , Wang Chunsheng , Xu Kang
Published: February 2020

The application of Li-ion batteries for vehicle-electrification and grid-storage is deterred by their safety, environmental and cost concerns, which are mainly imparted from the non-aqueous electrolytes used therein. These obstacles could be circumvented by an aqueous alternative; however, narrow electrochemical stability window (1.23 V) of the latter, imposed by hydrogen and oxygen evolutions at anode and cathode, respectively, sets an intrinsic limit on the practical voltage and energy output of an aqueous Li-ion cell. Here, we report a new aqueous electrolyte, whose electrochemical stability window was expanded to ~3.0 V via super-concentration and concomitant interphasial chemistry. A full Li-ion battery of 2.3 V was demonstrated to cycle over 1000 times in this electrolyte, with nearly 100% Coulombic efficiency at both low (0.15 C) and high (4.5 C) rates. For the first time, breaking Pourbaix-limits makes it possible for an aqueous Li-ion chemistry to deliver energy density over 100Wh/kg.
The Intriguing Question of Anionic Redox in High-Energy Density Cathodes for Li-Ion Batteries
Authors: Saubanère Matthieu , McCalla Eric , Tarascon Jean Marie , Doublet Marie-Liesse
Published: February 2020

The energy density delivered by a Li-ion battery is a key parameter that needs to be significantly increased to address the global question of energy storage for the next 40 years. This quantity is difficult to improve when materials exhibit a classical cationic redox activity.

Recently, a cumulative cationic (M4+/M5+) and anionic (2O2-/(O2)n-) redox activity has been demonstrated in the Li-rich Li2MO3 family of compounds, therefore enabling doubling the energy density with respect to high-potential cathodes such as transition  metal phosphates and sulfates.

This paper aims at clarifying the origin of this extra capacity by addressing some fundamental questions regarding reversible anionic redox  in high-potential  electrodes for Li-ion batteries. First, the ability of the system to stabilize the oxygen holes generated by Li-removal and to achieve a reversible oxo- to peroxo-like (2O2-/(O2)n-) transformation is elucidated by means of a metal-driven reductive coupling mechanism. The penchant of the system for undergoing this reversible anionic redox or releasing O2 gas is then discussed  in regards to experimental results  for 3d- and 4d-based Li2MO3 phases.

Robust indicators are built as tools to predict  which materials in the Li-rich TM-oxides family will undergo efficient and reversible anionic redox.  The present finding provides insights into new directions to be explored for the development of high-energy  density materials for Li-ion batteries.
Challenges to All-Solid State Battery for Sustainable Mobility
Authors: Kotani Yukinari
Published: February 2020

For a practical electric vehicle to be widely accepted in the market, development of next generation batteries with high energy density is critical. So far, Toyota is promoting battery R&D from both the engineering and scientific point of view, and we believe All-Solid State battery using an inorganic solid electrolyte has great potential as a candidate for beyond Li-Ion battery technology.  There are several benefits such as no potential for leakage, a wide electrochemical window, and high thermal stability and these properties enable the design of a series, multi-layer cell, which would result in a high voltage and robust energy device even in harsh environments. In my presentation, I will introduce the current challenges and update some results of Toyota’s All-Solid State battery program.
Visualization of Electrochemical Reactions in Battery Materials with X-ray Microscopy
Authors: Cabana Jordi
Published: February 2020

In this talk, I will discuss examples of the visualization of phase transformations using a variety of modes within the general family of X-ray microscopy, tailored to suit the scales and phenomena to be probed, but focusing on single particles.  Because thermodynamic pathways can be controlled by the presence of electrical potential, the harvesting of a sample from a cycled battery, while providing a useful preliminary insight, can lead to misleading results due to the relaxation of components into a different state that is more stable under open circuit conditions.  Therefore, measurements performed during the electrochemical reaction will be leveraged in this discussion.  The mechanisms of transformation will be related to their impact on material and architecture properties.
Electrode Modifications By Polymeric Coatings for Enhanced Performances of Li-Ion Batteries
Authors: Wu Nae-Lih
Published: February 2020

The properties of the interface between electrode active materials and electrolyte have profound effects on the performance of Li-ion batteries (LIBs). A large amount of research has so far been devoted to modifying the surfaces of active materials in order to enhance the overall performance of the electrodes. Majority of the research has resorted to inorganic oxide coatings, presumably due to their chemical stability, and different beneficial effects have been claimed for both cathode and anode materials. There have relatively been far fewer studies on polymeric coating. The rich chemistry of polymeric blend intrinsically provides great flexibility for dealing with wide varieties of active materials and electrolytes for maximum performance. In this presentation, several examples using designed polymeric blend coatings on various LIB electrodes, including graphite and Si anodes and a NCM cathode, to substantially enhanced electrode capacity, rate performance and/or high-temperature cycle stability will be presented.
Long-Life Silicon/Graphite Anode with Nano Carbon Coatings for Lithium Ion Battery - Graphene Nanowalls and Nitrogen Incorporated Ultrananocrystalline Diamond
Authors: Tzeng Yonhua , Pan Yen-ting
Published: February 2020

Although lithium ion batteries (LIBs) have been used in many consumer  and industrial products, the energy storage capacity per volume/weight and the battery cycling lifetime have much room for further improvement.  This is especially challenging for high demanding applications such as long-range electric vehicles, and smart grid renewable energy storage. Among LIB anode materials,  graphite is the most common one in the market today. Many novel anode materials have been studied in pursuit of much higher battery energy storage capacity for a given volume and weight. Among them, silicon is the most attractive one which theoretically is capable of storing more than ten times of energy than that of graphite anode for the same anode weight. However, silicon suffers from extensive volume expansion and shrinkage by about 400% when it cycles through fully charged and discharged states. The volume difference leads to breakage of silicon particles and the loss of their electrical contacts to the current collector and thus its capability of further discharging and charging. On the other hand, graphite has a layered structure, which suffers from breakage between adjacent layers into smaller pieces and thus possibly loses the capability of broken apart small graphite pieces in charging and discharging. Therefore, technologies for preventing aforementioned huddles against achieving long-life and high-capacity LIBs are highly desirable. Novel electrically conductive ultrananocrystalline diamond, graphene nanowalls, and diamond-graphene hybrid nano-carbon coatings have been applied by plasma enhanced chemical vapor deposition technique to graphite and silicon based LIB anodes and achieved much longer cycling lifetime compared to those without such nano carbon coatings. This paper will present the nano-carbon coating processes, materials characterization, LIB fabrication processes, and the characterization of LIB half cells which demonstrates enhance lifetime and charge storage capacity.