bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electroreduction of Nitrobenzene: Nominal Simulation of Voltammogram
Authors: Haque Inam ul 
Published: February 2020

For the electrochemical reduction of nitrobenzene in aqueous cationic micellar solution of cetyltrimethylammonium bromide [CTAB] at platinum electrode using cyclic voltammetry, a reversible/quasi reversible charge transfer reaction pertaining to one electron couple of ArNO2/ArNO2.- was indicated (1). Digital simulation was used to evaluate electrochemical kinetic parameters for the mono-electron transfer step (1).
An ECE mechanism, Scheme-1 and Figures 1 and 2 and Table-1, is suggested for the previously reported voltammograms (2) featuring nitrobenzene reduction on a coated platinum electrode partially covered by a thin film of dioctadecyldimethylammonium chloride [DODAC].

Table-1:
Diffusion coefficients for nitrobenzene (2)

Diffusion coefficient (cm2/s)

6.11×10-5
1.09×10-4

Bare Pt DODAC covered Pt, this work

References
(1) Tariq, M.; Haque, I. U., Science International (Lahore), 2016, 28, 361
(2) Haque, I. U.; Tariq, M., Journal of the Chemical Society of Pakistan, 2011, 33, 529

Figure 1
Electrochemical Homo-Coupling Reaction of Brominated Phenols
Authors: Obata Rika , Yamamoto Takashi , Naba Keisuke , Ohba Shigeru , Einaga Yasuaki , Nishiyama Shigeru 
Published: February 2020

Electrochemical homo-coupling reaction of brominated phenols was investigated. In the asymmetric synthesis, the structural motif of 2,2’-biphenyl provides chiral chelating ligand systems and therefore they are categorized as privileged chiral catalysts. Also, the 2,2’-biphenyl unit has been found as bioactive centers in several natural products. The 2,2’-biphenyl molecule with bromide functional group would be a useful synthetic tool to construct further C-C bond formation. However, synthetic methods to obtain brominated 2,2’-bipnenyls are less common, and direct coupling reaction of brominated phenols resulted with low to moderate yield. Recently we have found iodine mediated one step coupling reaction to construct brominated 2,2’-biphenyl from 4-brominated phenol. This reaction was applied to electrochemical reaction. The electrochemical reactions and results of the biological assay of the obtained compounds will be discussed.
Structural Manipulation of Carbon Nitride for Electrochemiluminescent Analysis
Authors: Zhang Yuanjian 
Published: February 2020

Chemical structures of two-dimensional (2D) nanosheet can effectively control the properties thus guiding their applications. However, carbon nitride nanosheets with tunable chemical structures and sizes has been rarely explored so far, thus impeding the further boost of performances. Herein, we demonstrate that carbon nitride nanosheets with tunable chemical structures can be obtained by liquid-exfoliation of facile accessible bulk carbon nitride with different polymerization degree. In comparison with previous methods for preparation of 2D nanosheets, the proposed route was green, not requiring any additives, toxic solvents or preintercalation steps. On the other hand, detection of metal-ions as known is crucial for health due to both deficiency and overdose of them will cause the imbalance of homestasis and subsequenet severe diseases. Interestingly, the ECL of as-prepared carbon nitride nanosheers (CNNS) was significantly modulated, and exhibited unusual changes in quenching and enhancement upon adding different metal-ions. Such advantage was further applied to construct sensors for multiple metal-ions without any labeling and masking reagents. The detection limit estimated at a signal-to-noise of 3, of Cu2+, Ni2+, and Cd2+ were 250 nM, 1 nM and 20 nM, respectively, which was 2~340 times lower than the maximum level in drinking water permitted by WHO. Detailed mechanism studies further revealed that the strong ECL quenching effect was due to the inner filter effect/electron transfer process and the enhancement was due to the catalytic effect. It would open a vista to explore 2D carbon-rich materials for a wide range of applications such as sensing with enhanced performances based on new mechanism.
Reference
[1]Zhou, Z.; Wang, J.; Yu, J.; Shen, Y.; Li, Y.; Liu, A.; Liu, S.; Zhang, Y. J. Am. Chem. Soc.
2015, 137, 2179.
[2] Zhou, Z.; Shen, Y.; Li, Y.; Liu, A.; Liu, S.; Zhang, Y. ACS Nano
2015, 9, 12480.
[3]Shang, Q.; Zhou, Z.; Shen, Y.; Zhang, Y.; Li, Y.; Liu, S.; Zhang, Y. ACS Appl. Mater. Interfaces
2015, 7, 23672.
Enhanced Electrochemiluminescence on Indium Tin Oxide Modified with Dendrimer-Encapsulated Nanoparticles
Authors: Kim Joohoon 
Published: February 2020

Here, we report enhanced electrochemiluminescence (ECL) on indium tin oxide (ITO) electrodes modified with amine-terminated dendrimers encapsulating catalytic nanoparticles, which can be applied for sensitive electrochemiluminescence(ECL)-based assay. Specifically, we prepared Pt and Au dendrimer-encapsulated nanoparticles (DENs) using amine-terminated polyamidoamine (PAMAM) dendrimers, and subsequently immobilized the DENs onto ITO surfaces via electrooxidative grafting of the terminal amines of dendrimers to the surfaces.[1] The resulting DEN-modified ITOs preserved good optical transparency of ITO and exhibited highly catalyzed electrochemical oxidation of Ru(bpy)3
2+ (bpy, 2,2’-bipyridine)/ tri-n-propylamine (TPrA), leading to significantly increased ECL emission.[2] Especially, the Pt DEN-modified ITO electrode provides negligible transmittance drop, i.e. only ~1.99% over the entire visible region, and exhibited not only much enhanced (i.e., ~213-fold increase compared to ECL obtained from bare ITO), but also stable ECL emission under consecutive potential scans from 0.00 to 1.10 V for 10 cycles, which allowed ~329 times more sensitive ECL-based analysis of nicotine using the Pt DEN-modified ITO compared with the use of bare ITO. However, we observed relatively poor stability of Au DENs on the ITO surfaces.[2] We found that the poor stability of Au DENs is closely related with the presence of chloride ions in electrolyte solutions.[3] In the absence of chloride ions, we demonstrated that the Au DEN-modified ITOs could be used as a versatile ECL based platform for sensitive electroanalysis of reactive oxygen species (ROS), such as hydrogen peroxide.
[1] S. B. Lee, Y. Ju, Y. Kim, C. M. Koo, and J. Kim, Chem
. Com
un
.
2013, 49, 8913.
[2] Y. Kim and J. Kim, Anal
. C
hem
.
2014, 86, 1654.
[3] Lee, S. B.; Kwon, J.; Kim, J. Electroanalysis
2015
, 27, 2180-2186.
Liquid Junction Potential Between Hydrophobic Ionic Liquid and Aqueous Electrolyte Solution
Authors: Yamamoto Masahiro , Kawai Kenji , Kakiuchi Takashi , Murakami Ryo 
Published: February 2020

The liquid junction potential (LJP) across the two phases is very important for the basic science and real application of electrochemistry. In the case of the reference electrode the KCl salt-bridges are widely used, because the diffusion potential can be neglected in some cases by the almost same mobility of potassium ion and chloride ion in aqueous solution. However, if the difference of the concentration of solute between the two phases is great the LJP becomes several ten mV. And in the KCl salt-bridge KCl solution flow from reference electrode to the sample solution is essentially inevitable. To overcome these shortcomings of KCl salt bridge Kakiuchi et al. introduced the ionic liquid salt bridge (ILSB) concept and found that　LJP for ILSB is always constant and independent on the concentration of electrolyte in aqueous phase. The LJP for ILSB is distribution of cation an anion of IL to aqueous solution.[1]
In the present study we have measured the electric conductivity of lithium bis(pentafluoroehtanesulfonyl)amide (LiC2C2N) and bis(pentafluoroethanesulfonyl)amide acid(HC2C2N) in aqueous solution. C2C2N anion is the ionic liquid component of ILSB and the cation is tributyl(2-methoxyethyl)phosphonium (TBMOEP). Form the conductivity measurements we have found that the molar conductivity at infinite dilution of C2C2N anion is 28.1 ± 0.7 S cm2 mol-1 and mobility is 2.91 × 10-4 cm2 V-1 s-1. Sakaida et al. reported the solubility of TBMOEP cation in aqueous solution is 2.64 x 10-4 cm2 V-1 s-1.[2] From these results we can estimate the diffusion potential across TBMOEPC2C2N | HCl solution using the Henderson equation. Even in the case of 0.5 mmol dm-3 the magnitude of the diffusion potential is 60　microvolt and the we can conclude that the diffusion potential is negligible in the TBMOEPC2C2N ILSB. We are now investigating the coupled Nernst-Plank and Poisson-Boltzmann equation to see the detail of the potential and the concentration profile.
From the conductivity measurements we also found that HC2C2N is strong acid and C2C2N anion in aqueous phase is completely dissociated.
References
[1] T. Kakiuchi and T. Yoshimatsu,　Bull. Chem. Soc. Jpn. 79, 1017-1024 (2006).
[2] H. Sakaida, Y. Kitazumi, and T. Kakiuchi, Tantala, 83, 663-666 (2010).
Highly Efficient Electrogenerated Chemiluminescence of Au22SG18 Nanocluster in Aqueous Solution
Authors: Kim Jaeyoon , Pyo Kyunglim , Lee Dongil , Lee Won-Yong 
Published: February 2020

Quantum sized metal nanoparticles have attracted wide attention in recent years because of their large potential of application. Among various metal nanoparticles, Au22SG18 nanocluster has unique optical and electrochemical properties. The Au22SG18nanocluster consist of 22 gold atoms and 18 thiolate ligands. In this study, the Au22SG18 nanocluster is synthesized and its electrogenerated chemiluminescence (ECL) properties have been characterized for the detection of amine compounds such as tripropylamine (TPA) and 2-(dibutylamino) ethanol (DBAE). Especially, ECL of Au22SG18 nanocluster can be generated in aqueous phase. Highly efficient ECL is achieved by using potential pulse method, which increases the ECL intensity. Experimental pulse condition has been optimized. The experimental result demonstrates that the ECL of Au22SG18 nanocluster holds great promise of ECL application in analytical sciences.
Specific Surface Nitride Groups on Glassy Carbon Model Surfaces to Catalyze the Vanadium Redox Reactions
Authors: Greese Tobias , Friedrich Franziska 
Published: February 2020

Vanadium redox flow batteries currently have come closer to their suitability in the industrial as well as the private sector. However, they still suffer from high capital costs, mainly ruled by the conversion unit consisting of an assembly of sandwiched components, such as semipermeable membranes and carbon electrodes (MEA). The respective system power output scales with and determines the necessary geometric area of the MEA. By increasing the area specific power output of a MEA capital costs may be reduced. As electrodes commonly porous graphite felt (GF) electrodes are used which are made of a woven of carbon fibers. When pumping the (sulfuric acid) electrolyte through these graphite felts, the Vanadium (V) ions dissolved in the electrolyte can pass the carbon surface of the fibers where the anodic V2+/3+ and the cathodic V4+/5+ redox reactions take place, respectively. A big portion of the power losses result from the kinetic overpotentials that need to be applied on the porous carbon electrodes in order to drive the Vanadium reactions.(1)

In recent years various modification methods of the carbon electrodes have been proposed.(2,3) Besides surface oxide groups there were a few attempts that involved nitrogen atoms which were supposed to offer a catalytic activity for the Vanadium reactions. This work aims to resolve the variable catalytic activity coming from distinctive nitride surface groups.(4,5)

For this purpose, on glassy carbon there were synthesized artificial aromates containing a nitro group, which covalently bind to the carbon surface and provide an anchor site for the Vanadium redox reaction. The synthesis method is resulting in a narrow distribution of architecture of different surface nitrides. This allows for an exclusive examination of the catalysis of distinctive, specific nitrogen involving surface groups for the Vanadium reactions and shows pathways for advanced modification methods.
Experimental results will comprise rotating disk electrode (RDE) measurements in an electrochemical half-cell. Moreover, x-ray photoemission spectroscopy results depict the surface coverage of the newly created adsorbants. In addition, the performance and changed efficiency of a single cell is presented, which is equipped with GF electrodes comprising the surface nitrides evaluated before.
The project is financially supported by the Bavarian Ministry of Economics.

(1) Parasuraman et al. Electrochimica Acta (2013) 101 27–40.

(2) J.-Z. Chen et al. Journal of Power Sources (2015) 274 894–898.

(3) K.J.Kim et al. Mat. Chem. And Phys. (2011) 131 547-553.

(4) S. Wang et al. J. Phys. Chem. Lett. (2012) 3 2164−2167.

(5) Y. Shao et al. Journal of Power Sources (2010) 195 4375–4379.
Electrochemistry of Superatomic M@Au24(SR)18 (M=Pd, Pt) Clusters and Their Application in Electrocatalysis
Authors: Kwak Kyuju , Choi Woojun , Kim Minseok , Tang Qing , Jiang De-en , Lee Dongil 
Published: February 2020

Atomically precise gold clusters containing from a few to a few hundreds of atoms have been the focus of recent investigations because of their unique electronic structures with high chemical and thermodynamic stability. In particular, the extraordinary stability of these superatom-like gold clusters, for example [Au25(SR)18]- where SR is organothiolate, arises from the closure of superatomic electron shells, leading to a noble-gas-like 8-electron configuration (1S21P6). In this presentation, we report that replacing the core Au atom with Pd or Pt results in stable bimetallic clusters, [MAu24(SR)18]0 (M = Pd, Pt), having a superatomic 6-electron configuration (1S21P4). These clusters exhibit dramatically different optical and electrochemical properties from those of the 8-electron [Au25(SR)18]-. The highest occupied molecular orbital−lowest unoccupied molecular orbital gaps of [PdAu24(SR)18]0 and [PtAu24(SR)18]0 determined by voltammetry were drastically decreased to 0.32 and 0.29 eV from that of [Au25(SR)18]- (1.32 eV), respectively, indicating their electronic structures were significantly altered upon doping of the foreign metal. The unique electrochemical properties observed from the stable bimetallic clusters suggest that doping of a cluster is a powerful means to fine-tune the redox properties of the cluster, offering special advantages in the development of new functional electrocatalysis. Voltammetric investigation shows that the PtAu24(SR)18 cluster exhibits exceptionally high catalytic activity for hydrogen evolution reaction (HER). The origin of the extraordinary catalytic activity of this cluster is discussed along with reaction mechanisms.
Electrochemical Reduction of 2,2-Dichlorovinyl Dimethyl Phosphate (Dichlorvos) at Carbon and Silver Cathodes
Authors: Mali Sonali , Peters Dennis G 
Published: February 2020

Despite their negative ecological effects, halogenated organophosphates have been used as pesticides. For example, 2,2-dichlorovinyl dimethyl phosphate (or dichlorvos), found in many household and commercial insecticides, can lead to contamination of runoff and rinse water that is toxic to birds, bees, aquatic organisms, and mammals. Remediation of dichlorvos has focused either on electrochemical oxidation1 or on reductive cleavage of its carbon–chlorine bonds at mercury.2
In this study, we have examined the direct reduction of dichlorvos in dimethylformamide and acetonitrile at both carbon and silver cathodes.

Shown in Figure 1 are cyclic voltammograms for reduction of dichlorvos at both carbon and silver electrodes. Whereas reduction of dichlorvos at carbon shows a single irreversible cathodic peak, reduction at a silver electrode results in two overlapping cathodic peaks. Controlled-potential (bulk) electrolyses at potentials corresponding to those of the voltammetric peaks indicate that dichlorvos undergoes carbon–chlorine bond cleavage. Catholytes have been analyzed by means of gas chromatography–mass spectrometry (GC–MS) to separate, identify, and quantitate the electrolysis products.

References

1. Lu, M.-C.; Chen, J.-N.; Chang, C.-P. Chemosphere, 1997, 35, 2285–2293.

2. Subbalakshmamma, M.; Reddy, S. J. Electroanalysis
1994, 6, 521–526.

Figure 1
Mechanism of CO2 Capture in 1-Alkyl-3-Methylimidazolium Acetate: Is N-Heterocyclic Carbene Involved?
Authors: Kim Hyung J , Yan Fangyong , Dhumal Nilesh R 
Published: February 2020

Ionic liquids (ILs) offer a promising alternative absorbent for CO2 capture because of their unique properties, such as negligible vapor pressures, high thermal stabilities, excellent CO2 solubilities and tunability. More importantly, ILs consisting of 1-alkyl-3-alkyl’-imidazolium cations paired with acetate anions can react with CO2 and form carboxylate compounds. N-heterocyclic carbene that can be formed via proton transfer from an imidazolium cation to an acetate anion is often invoked in the mechanistic explanation of these CO2–IL reactions. However, the detection of the carbene species has been elusive experimentally. In this talk, we present our results for classical and ab initio molecular dynamics simulations as well as for density functional theory calculations to gain molecular insight into CO2 capture by 1-ethyl-3-methylimidazolium acetate. Our analysis indicates that N-heterocyclic carbene is not formed and thus not involved in CO2 capture at room temperature. Based on our computational results, a novel concerted mechanism is proposed.
Protective Ceramic Coatings on the Base of the Refractory Metals Carbides
Authors: Stulov Yuriy V. , Dolmatov Vladimir S. , Kuznetsov Sergey A. 
Published: February 2020

The aim of this work was obtaining of the protective coatings of the refractory metal carbides such as NbC, TaC, Cr7C3 on carbon steels and carbon fibers with further study their properties.
The refractory metal carbides NbC, TaC, Cr7C3 were deposited on carbon steel and fibers by currentless transfer in molten salts at temperatures 1073-1123 K. The microhardness of refractory metal carbides on carbon steels at the cross section had the values 21 GPa, 29 GPa, 31 GPa for Cr7C3, NbC and TaC, respectively. The corrosion resistance of these carbides was studied in concentrated HCl, H2SO4 and H3PO4 acids at a room temperature during 48 hours. The corrosion tests were shown following rows of the chemical stability carbide coatings in HCl: Cr7C3>NbC>TaC; in H2SO4: TaC>Cr7C3>NbC; in H3PO4: Cr7C3>TaC>NbC. The wear resistance was evaluated by the mass loss of samples. The mass loss of a sample from a hardened St.3 was 35.2 mg cm-2 and that of a coated with a chromium carbide – 4.7 mg cm-2, niobium carbide – 2.9 mg cm-2 and tantalum carbide – 2.2 mg cm-2. Deposition of NbC coatings on parts of oil pumps increased their lifetime in several times. Coatings of Cr7C3 or TaC on the knifes for cutting rubber, made of St. 3, improve their wear resistance and increase a tool life in 2.0 – 2.5 times, respectively. Coatings of NbC or TaC on carbon fibers improve the mechanical resistance and they are compatible with fibers up to 1473 K in an aggressive atmosphere.
Effect of Electrolyte Composition on the Current Efficiency for Aluminium Deposition from Molten Fluoride Electrolytes with Dissolved Alumina
Authors: Morishige Taiki , Haarberg Geir Martin , Gudbrandsen Henrik , Skybakmoen Egil , Solheim Asbjørn 
Published: February 2020

Aluminium is produced by electrolysis in molten cryolite alumina electrolytes according to the Hall-Heroult process. The current efficiency for aluminium in modern cells can be as high as 96 %. The main reason for loss in current efficency is the socalled back reaction between dissolved aluminium and the anode product CO2.
A laboratory cell to determine the current efficiency was recently modified to obtain more reliable results. Electrolysis was performed at constant current density, and the amount of deposited aluminium was determined. Effects of electrolyte composition and temperature were studied. The loss in current efficiency is strongly linked to the solubility of dissolved aluminium. Realistic values for the current efficiency were obtained. Further experiments to study effects of additions of impurities are under way.
"Solvate" Ionic Liquids, "Solvent-in-salt" Ionic Liquids, and "Deep Eutectic" Ionic Liquids. What are the Relationships - and the Ionicities?
Authors: Angell C Austen , Hasani Mohammad 
Published: February 2020

Recently, in the search for alkali metal-containing electrolytes with higher conductivities than available in common ionic liquid systems, some interesting
systems have shown up. The most interesting ones are those that also have wide electrochemical windows and high alkali metal transport numbers, and when non-flammability is also included, the interest has indeed run high1
,
2. The aqueous systems ("water-in-salt" electrolytes) are the most recent on the scene, and are of special importance for obvious reasons, but they are closely related in principle to other also successful systems developed independently in different labs and so given different designations. All are characterized by being extremely concentrated in ions but modulated in properties by the presence of one or other type of molecular constituent in molar proportions up to 50% and in some cases greater. Some other examples, are the "solvate ionic liquids" of the Watanabe3 and Henderson4 laboratories in which Li+ ions exist 1:1 with polyglyme molecules, and the "deep eutectic" liquids used by Abbott and coworkers5 for the electrodeposition of higher valent metals, where again the autoionization of the multivalent ions is induced by equimolar proportions of a favorable (often oxygenic) ligand. Both are special cases of the more general "solvent-in-salt" class of electrolyte from the Chen-Armand collaboration6. In this talk we will review the relationship between these different types of ionic systems and examine their relative ionicities, ionic mobilities, and other key characteristic properties.

1 Suo, L. et al. “Water-in-salt” electrolyte enables high-voltage aqueous lithium-ion chemistries. Science
350, 938-943 (2015).
2 Suo, L. et al. Advanced High Voltage Aqueous Li-ion Battery Enabled by “Water-in-Bisalt” Electrolyte. Angewandte Chemie Int. Ed. (printed online) DOI (2016).
3 Ueno, K. et al. Glyme−Lithium Salt Equimolar Molten Mixtures: Concentrated Solutions or Solvate Ionic Liquids? J. Phys. Chem. B
116, 11323-11331 dx.doi.org/11310.11021/jp307378j (2012).
4 Henderson, W. A. Glyme-lithium salt phase behavior. . J. Phys. Chem.
110, 13177-13183 (2006).
5 Abbott, A. P., Barron, J. C., Rydere, K. S. & Wilson, D. Chem.–Eur. J.
13, 6495. (2007).
6 Suo, L., Hu, Y.-S., Armand, M. & Chen, L. A new class of Solvent-in-Salt electrolyte for high-energy rechargeable metallic lithium batteries. . Nat. Commun.
4, 1481 (2013).