bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plasmonics Enhanced Spectroscopic and Electrochemical Analysis
Authors: Xia Xing-Hua 
Published: February 2020

The localized surface plasmon resonance (LSPR) arises from the collective oscillation of conduction electrons of metal nanostructures which can be used to monitor recognition events of biomolecules at single nanoparticles1. The enhanced electric field around the nanostructures due to LSPR will significantly enhance the Raman scattering, fluorescence and IR spectra, which enable the realization of single molecule detection. In addition, the LSPR will excite high-energy electron-hole pair (referred to as “hot electrons” and “hot holes”) emerging on metal surface. The energetic charges will considerably affect the electrochemical reactions occurring at the nanoparticles. When the plasmonic metallic nanostructures are coupled to other substrates, for example, the semiconductor (i.e., TiO2, MoS2), the plasmon-excited hot electron-hole at nanoparticle surface can communicate with the conductance and valence bands of the semiconductors, resulting in variation in electro/photocatalytic activity. In this talk, we will start with the study on the possibility of LSPR for monitoring biomolecules and their recognition events at single nanoparticles.1 Then, we report the LSPR enhanced IR for biosensing.2 In the third part, we will show how the LSPR accelerates electrochemical reactions of electroactive biomolecules such as glucose on gold nanoparticles and hydrogen evolution reaction at molybdenum disulphide nanosheets.3 Based on the plasmonics accelerated electrochemical reactions (PAER), high sensitive electrochemical biosensors for detection of glucose and other electroactive biomolecules have been constructed.
1. (a) Y. Zhao, et al. Anal. Chem. 2013, 85: 1053; (b) B. Jin, et al. Langmuir, 2012, 28: 9460; (c) J.Y. Xu, et al. Chem. Comm. 2012, 48: 3052; (d) W.J. Bao, et al., Chem. Commun. 2014, 50: 7787; (e) Y. Zhao, et al. Chem. Commun. 2014, 50: 5480.
2. (a) J.Y. Xu, B. Jin, Y. Zhao, K. Wang, X.H. Xia, Chem. Commun. 2012, 48: 3052; 187. (b) B. Jin, G. X. Wang, D. Millo, P. Hildebrandt, X. H. Xia, J. Phys. Chem. C 2012, 116: 13038; (c) B. Jin, W. J. Bao, Z. Q. Wu, X. H. Xia, Langmuir 2012, 28: 9460; (d) J. Y. Xu, T. W. Chen, W. J. Bao, K. Wang, X. H. Xia, Langmuir 2012, 28: 17564; (e) W. J. Bao, Z. D. Yan, M. Wang, Y. Zhao, J. Li, K. Wang, X. H. Xia, Z. L. Wang, Chem. Commun. 2014, 50: 7787.
3. (a) Y. Shi, J. Wang, C. Wang, T.T. Zhai, W.J. Bao, J.J. Xu, X.H. Xia, H.Y. Chen, J. Am. Chem. Soc. 2015, 137: 7365; (b) 3. C. Wang, Y. Shi, X.G. Nie, Y. Zhou, J.J. Xu, X.H. Xia, H.Y. Chen, Science Advances, in revision.
Enabling Local Electrochemistry in Fast, High-Resolution Scanning Probe Microscopy
Authors: Kirchhofer Nathan D. , Proksch Roger , Rutgers Maarten , Revenko Irene 
Published: February 2020

Due to their exceptional sensitivity, scanning probe microscopes enable detailed interrogation of surfaces and interfaces. When correlating spatial information to additional scanning probe surface measurements (such as force, electrical potential or conductivity, impedance, thermal mapping, viscoelastic parameters, redox activity, and more), spatial resolution is often limited. In this work, we present the development and demonstrate the utility of an electrochemical assembly (probe, potentiostat, and sample cell) for use with a high-resolution, fast scanning Cypher atomic force microscope that enables measurements of highly-localized electrochemical signals. These measurements bear on various metrologies such as electrochemical scanning tunneling microscopy (EC-STM), scanning electrochemical microscopy (SECM), and electrochemical strain microscopy (ECSM), and relevant results will be presented.
Figure 1. The first-generation electrochemical cell for use with a lower-resolution scanning probe microscope.

Figure 1
Mesoporous Hollow MnO2 nanotubes Confined Sulfur As Cathode
Authors: Diao Guowang , Wu Zhen , Ni Lubin 
Published: February 2020

The lithium–sulfur battery is receiving intense interest because its theoretical energy density exceeds that of traditional lithium-ion batteries at a much lower cost, but practical applications are still hindered by capacity decay caused by the polysulfide shuttle. Here, we fabricate the mesoporous hollow MnO2 nanotubes as efficient sulfur hosts. To begin with, the self-standing carbon nanofibrous membranes are prepared via electro spinning and high-temperature carbonization, followed by an in situ redox reaction in KMnO4 solution to coat the carbon nanofiber (CNF) template with MnO2 nanosheets until the CNFs are consumed. The synthesized mesoporous hollow MnO2 nanotubes are composed of an inner shell of packed MnO2, and an outer shell of mesoporous sheet like MnO2, which provide physical confinement and chemical interaction and show excellent efficiency for trapping the polysulfides. With a high sulfur content of 73 wt%, in the composite and a areal sulfur mass loading of 2 mgcm-2 in the electrode, the sulfur- mesoporous hollow MnO2 nanotubes electrode delivered a specific capacity of 1213 mAhg-1 at 0.5 C and maintained a stable cycling performance at 1 C over 300 cycles.

References

[1] Huang Y, Liang Z, Miao Y E, et al. Diameter-Controlled Synthesis and Capacitive Performance of Mesoporous Dual-Layer MnO 2 Nanotubes[J]. Chemnanomat, 2015, 1(3):159–166.
[2] Liang X, Hart C, Pang Q, et al. A highly efficient polysulfide mediator for lithium–sulfur batteries[J]. Nature Communications, 2015, 6:5682-5682.
[3] Zhen L, Jintao Z, Lou X W D. Frontispiece: Hollow Carbon Nanofibers Filled with MnO2 Nanosheets as Efficient Sulfur Hosts for Lithium-Sulfur Batteries.[J]. Angewandte Chemie International Edition, 2015, 54(44) .

Acknowledgement

This work was financially supported by the National Natural Science Foundation of China (Grant No. 21273195), a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
Core/Shell Fe3O4@PANI and Fe3O4@C@PANI Nanospheres Nanospheres Nanocomposites for High-Performance Electrochemical Supercapacitors
Authors: Diao Guowang , Wu Qianhui 
Published: February 2020

Abstract: In this work, magnetite (Fe3O4)-based core/shell composites, including Fe3O4@carbon (C), Fe3O4@polyaniline (PANI), and Fe3O4@C@PANI, are synthesized via a facile hydrothermal process. The as-prepared core/shell composites are characterized by transmission electron microscopy, X-ray diffraction powder, and Fourier transform infrared spectroscopy. The electrochemical performances of Fe3O4,Fe3O4@C, Fe3O4@PANI, and Fe3O4@C@PANI are investigated using cyclic voltammetry, galvanostatic charge–discharge measurement, and electrochemical impedance spectroscopy. The results show that the as-prepared nanomaterials are all typical pseudocapacitance capacitors. Carbon shell can significantly increase the electronic conductivity of electrode materials, reduce capacity loss, and improve the reversibility of Fe3O4. PANI coatinglayer can expressively enhance the specific capacitance.Synergistic effect of double shells improves the electrochemical property of Fe3O4.Fe3O4@C@PANI composites display the high capacitance of 322.5 F g-1at 2.5 A g-1,and 87.8 % of which can still be maintained after 3000 charge–discharge cycles. The excellent electrochemicalproperties of Fe3O4@C@PANI evidence their potential application as supercapacitors in energy storage field.

Reference

[1]. Winter M, Brodd RJ (2004) What are batteries, fuel cells, and supercapacitors? Chem Rev 104:4245–4270
[2]. Ko¨tz R, Carlen M (2000) Principles and applications of electrochemical capacitors. Electrochim Acta 45:2483–2498
[3]. Simon P, Gogotsi Y (2008) Materials for electrochemical capacitors. Nat Mater 7:845–854

ACKNOWLEDGEMENTS

This work was financially supported by the National Natural Science Foundation of China (Grant No. 21273195),a Project Funded by the Priority Academic Program Development of
Jiangsu Higher Education Institutions, and the Natural ScienceFoundation of Education Committee of Jiangsu Province(12KJB150023).
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Study about an Experimental Design for CdTe Quantum Dots Synthesis. Analysis of the Optical and Electrochemical Changes after Their Interaction with Hydroxyl Radicals
Authors: Muñoz Eduardo Carlo , Navarrete Emilio Alonso , Henríquez Rodrigo Gonzalo , Schrebler Ricardo Silvio , Córdova Ricardo Alejandro , Aguilar Luis Felipe , Bravo Manuel Andrés 
Published: February 2020

Quantum dots (QDs) are semiconductor nanocrystals with diameters in the range of 2-10 nm (10 to 50 atoms) and which exhibit electronic properties between bulk materials and molecules [[i]]. Considering their optical properties, fluorescence processes exhibit real applications in sensor and biosensors fields. In fact, the fluorescent properties of these materials can be tuned depending on the particle size. Generally, a decrease of the QDs size produces an increase in the energy gap between the valence and the conduction band, which induces to a shifted of the emission wavelength toward shorter values [[ii]].
In this work we examined an optimization of the synthesis parameters of CdTe QDs using a Doehlert experimental design. The synthesis employed Na2TeO3 and CdCl2 as precursors, mercaptosuccinic acid (MSA) as capping agent, NaBH4 as reducing agent and Borax/Citrate as buffer in a reflux system. The synthesis parameters optimized were: temperature, pH, molar ratio of precursors and reaction time.
After, an analysis of the optical and electrochemical changes after the interaction with hydroxyl radicals was carried out. The optical changes were studied by time-resolved fluorescence measurements evaluating the fluorescence lifetime observing different quenching processes. On the other hand, changes in the differential capacitance of the QDs deposited on different electrodes were studied by means of Electrochemical Impedance Spectroscopy (EIS). The changes in these properties were studied in absence and presence of hydroxyl radicals produced by a Fenton reaction.

[
[i]
] Ekimov, A. I. & Onushchenko, A. (1981). "Quantum size effect in three-dimensional microscopic semiconductor crystals". JETP Lett. 34: 345–349.

[
[ii]
] Medintz I L, Clapp A R, Brunel F M, Tiefenbrunn T, Uyeda H T, Chang E L, Deschamps J R, Dawson P E and Mattoussi H. Nature.
Mater. (2006) 5:581.

Figure 1
Preparation and Characterization for Ionic Liquid Coated Graphene Oxide Nanoparticles
Authors: Chen Songqing , Zhu Xiashi 
Published: February 2020

The tremendous potential of ionic liquids (ILs) as an alterna-tive to environmentally harmful ordinary organic solvents is well recognized. ILs have attracted extensive attention and gainedpopularity in analytical chemistry [1] covering different application fields like chromatography, electrochemistry or extraction techniques [2].
Three hydrophobic ionic liquids (ILs) including 1-butyl-3- methylimidazole hexafluorophosphate ([BMIM]PF6), 1-hexyl-3-methyl-imidazole hexafluorophosphate ([HMIM]PF6), and 1-octyl-3- methylimidazole hexafluoro- phosphate ([OMIM]PF6) coated graphene oxide (GO) nanoparticles. The synthesized GO@ILs composite materials were characterized by FT-IR spectroscopy and scanning electron microscopy (Fig.1).
The GO@ILs composite materials exhibited much higher specific capacitance than unmodified GO. It would be interesting for future research to 1) evaluate long-term performance over several thousand charge–discharge cycles, 2) control the extent of functionalization with ionic liquids, 3) attempt to decouple double-layer and pseudocapacitance, if possible, and 4) performelectrochemical experiments in ionic liquid electrolytes to open the voltage window and increase energy storage capabilities[3].

Figure 1
Approaches for Extractive Hydrometallurgy of Niobium and Tantalum from Ethiopian Kenticha Ores
Authors: Berhe Goitom Gebreyohannes 
Published: February 2020

A Review Approaches for Extractive hydrometallurgy of niobium and tantalum from Ethiopian Kenticha Ores Abstract
The Kenticha rare-element pegmatite, a globally important tantalite source in the Neoproterozoic of southern Ethiopia, is a highly fractionated, huge, subhorizontal, sheet-like body, discordantly emplaced in ultramafic host rock. It corresponds to the spodumene subtype of the rare element pegmatite class and belongs to the lithium–cesium–tantalum petrogenetic family. The Kenticha pegmatite is asymmetrically zoned from bottom to top into granitic lower zone, spodumene-free intermediate zone, and spodumene-bearing upper zone. The Kenticha pegmatite is rich in Ta-mineralized rare-element pegmatites. Thus, need to conduct research in enrichment of Ta2O5 and Nb2O5 and extraction of Nb and Ta into metallic form.
This paper reviews the successful extraction of Nb and Ta from tanatlite ores. Its success normally depends on the physiochemical properties of the ore, choice of leaching extraction solvent. Currently, HF and methyl-isobutyl Ketone has been used for decomposition and separation of Nb and Ta from tantalite ore. Therefore Kenticha atantalite ore containe vaiaty compositions of elements and higher concentration of Li and U. Thus needs further investigation in extraction process in the sence of removing the use of HF for leaching and replacement of traditional organic solvents by “Green Solvents”. This review gives directions for future development of extraction of Kenticha tantalite ore.

Keywords: Kenticha; leaching; magnetic separation; pegmatite, rare-element; solvent extraction, sopdumene; tantalite.
Fabrication of TiO2 Based Microspheres By Spray Drying Method and Their Application for Dye-Sensitized Solar Cells
Authors: Mizuno Maho , Tomita Koji , Kunugi Yoshihito 
Published: February 2020

Dye-sensitized solar cells (DSSCs) have received considerable attention since Grätzel et.al.reported a high conversion efficiency using nanocrystalline mesoporous TiO2 film. A typical DSSC consists of a transparent conductive oxide, semiconductor oxide, dye sensitizer, electrolyte and counter electrode. The working electrode is a nanoporous semiconductor oxide that is placed on conducting glass and is separated from the counter electrode by only a thin layer of electrolyte solution. The photoanode of DSSCs is typically constructed using a thick film (~20 μm) of TiO2 or, less often, ZnO or SnO2 nanoparticles. The TiO2 film has a large inherent absorptive surface area for light scattering.
Recently, TiO2 microspheres are of great interest for a great deal of applications, especially in the solar cell ﬁeld. Because of their unique microstructure and light-scattering effect, TiO2 microsphere-based solar cells often exhibit superior photovoltaic performance. Hence, exploring new suitable TiO2 microspheres for high-efficiency solar cells is essential. In this study, we reported the fabrication of TiO2microspheres by a simple spray drying process, and applied for Dye-sensitized Solar Cells.
TiO2 Microspheres were fabricated by spray drying method. TiO2 paste was prepared as follows, TiO2 microspheres (0.2g) was mixed into ethanol (1.8g). The resulting TiO2 paste was printed by doctor blade method on fluorine-doped SnO2-coated (FTO) glass electrodes and sintered at 500 °C for 30 min. DSSCs were prepared by a conventional procedure.
We are successfully fabricated TiO2 microspheres by spray drying method. According to SEM images of the TiO2 microspheres, particle size was ca. 3mm. We made microsphere TiO2 based DSSCs, and their energy conversion efficiency was 6.5% under AM 1.5 simulated full sunlight (100 mW cm−2) illumination.
Selenium-Decorated Graphene for Peroxynitrite Detection
Authors: Kalil Haitham , Maher Shaimaa , Bayachou Mekki 
Published: February 2020

Peroxynitrite (PON, ONOO−) is a member of the reactive oxygen-nitrogen species family. PON is generated in vivo by the diffusion-limited reaction (~2×1010 M−1S−1) of nitric oxide (
·
NO) and superoxide (O2

·

−) radicals. Elevated peroxynitrite levels are associated with several human pathologies, such as arthritis, inflammation, and carcinogenesis, as well as ageing-associated diseases. Thus, the precise detection of this species in biological systems is crucial, not only to understand the genesis and causes of ailments at the tissue/cellular level, but also to suggest and design potential therapies.
The essential trace element selenium (Se) is the catalytic cofactor of important endogenous antioxidative systems of the human body. In the past decade, selenium attracted the attention of many research groups for the understanding of fundamental biological functions and biomimetic applications. Selenium is found in several human proteins (selenoproteins), many of them involved in anti-oxidant defense systems. Therefore, selenium plays a key role in redox regulation as a modulator of reactive oxygen species (ROS). Recently, a number of novel synthetic organoselenium compounds has been prepared and used as antioxidants in medicinal chemistry such as ebselen.
In this work, we prepare and investigate interfaces based on the electrochemical deposition of selenium nanoparticles. We prepared surfaces of electrodeposited elemental selenium (Se) and selenium-decorated graphene-based nanostructures on glassy carbon electrodes and carbon fiber microelectrodes. We have used several physicochemical methods to characterize these PON-sensitive interfaces, including Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDX), X-ray Photoelectron Spectroscopy (XPS), Raman spectroscopy, and UV-vis on ITO transparent electrodes. We tested these interfaces for electrocatalytic sensing of peroxynitrite. We found that selenium-modified graphene platform is sensitive to peroxynitrite in solution, and it provides a viable interface for electrochemical sensing of this analyte. We observed that there is a synergistic effect of the presence of graphene as a substrate for selenium nanoparticles in the electrocatalytic detection of PON. In this paper, we will present our findings using this new PON-sensitive interface. We will compare and contrast the performance of the various modified carbon electrodes in terms of PON sensitivity using cyclic voltammetry and dose-response chronoamperometry.
the Relationship Between Brightness of Aluminum Films Fabricated Using an AlCl3-1-Ethyl-3-Methylimidazolium Chloride-Toluene Bath and Molecular Structure of Additives
Authors: Gunji Takao , Kaneko Shingo , Tanabe Toyokazu , Ohsaka Takeo , Matsumoto Futoshi 
Published: February 2020

In our previous study, we showed that the addition of 4-pyridinecarboxylic acid hydrazide (4-PCAH) to an EMIC/AlCl3/toluene mixture improved the brightness of the deposited Al film [1]. The prepared Al films clearly reflect the characters on the surface so that the characters can be read. The reflectivity of the Al surface prepared with EMIC/AlCl3/toluene/4-PCAH was 84% at 450 nm; to the best of our knowledge, this is the highest value achieved. In this study, to elucidate why the addition of 4-PCAH to the EMIC/AlCl3/toluene bath effectively improves the brightness of the electrodeposited Al surfaces, a systematic series of molecules as additives were studied, and the results obtained for each molecule were compared carefully to determine the relationship between the brightness of the prepared Al surface and the molecular structure of the additive.
The effect of additives, such as 4-PCAH and its analogs, on the surface brightness, electrodeposition efficiency and chemical composition of prepared Al films was examined using SEM, visible light reflectance measurements and XPS. The decrease in the surface roughness of the Al films causes the high surface brightness. The strong relationship (Fig. 1) between the high brightness and molecular structure of the additives included in the bath was elucidated via a systematic study of various additives. 4-PCAH achieved the highest surface brightness of the electrodeposited Al films prepared with various additives used in this study.
[1] X. Fang, K. Uehara, S. Kaneko, S. Sato, T. Tanabe, T. Gunji, F. Matsumoto, Electrochemistry 84 (2016) 17-24.

Figure 1. (A)Micrographs of the Al film surfaces obtained by the electrodeposition of Al from EMIC/AlCl3/toluene/4-PCAH baths, (B) Summary of the relationship between the reflectance of the prepared Al films at a wavelength of 450 nm and the molecular structure of the additive. Preparation conditions of the Al film: deposition time 2 h, constant current density 8 mAcm-2; bath composition: EMIC:AlCl3= 33.3 : 66.7 (mol%), toluene concentration: 9.25 M, additive concentration: 1.8 mM.

Figure 1
Electrochemical Properties of High-Voltage Spinel Positive Electrodes Prepared with Non-Fluorine PAN-Based Binders
Authors: Tanaka Shinichi , Narutomi Takuya , Suzuki Shigeru , Yabuuchi Naoaki 
Published: February 2020

For the application of lithium batteries with high energy density, high voltage spinel oxides are considered as promising candidates for a positive electrode of rechargeable lithium batteries. However, it is needed to reexamine the battery components including, electrolyte, conductive carbon, separator, and binder. In this study, we focused on the polyacrylonitrile (PAN) possessing high oxidation resistive properties, and synthesized non-fluorine PAN-based copolymer prepared by graft polymerization of PAN and an adhesive polymer. Electrochemical properties of LiNi1/2Mn3/2O4composite electrodes prepared with PAN-based copolymer are examined and compared with those of PVdF used as the binder.
LiNi1/2Mn3/2O4 was prepared by solid-state reaction from stoichiometric amounts of Li2CO3, NiCO3･2Ni(OH)2･4H2O, and MnCO3 at 1000 °C for 12 h followed by heating at 700 °C for 48 h in air.[1] Thus obtained sample was used as the positive electrode active material. PVdF (TA6010, Solvay) and non-fluorine PAN-based copolymer were used as binders. The electrode active material (AM) and acetylene black (AB, HS-100, Denka) were mixed with the binders, and NMP was added to adjust the viscosity of slurry. The slurry was uniformly pasted on to aluminum foil, and then dried in a vacuum. Compositions of electrodes were AM : AB : PVdF = 80 : 10 : 10 and AM : AB : PAN-based polymer = 80 : 10 : 5 in weight ratios. Electrochemical measurement was carried out using a two-electrode cell (TJ-AC, Tomcell Japan) consisting of the composite electrode, separator (polyolefin microporous membrane), electrolyte solution (LiPF6dissolved in EC : DMC = 3 : 7 by volume) and Li foil as a negative electrode.
Electrochemical properties of the LiNi1/2Mn3/2O4 composite electrodes prepared with different binders are compared in Li cells at 50 oC in Figure 1a. Reversible capacity of the composite electrode with non-fluorine PAN-based polymer reaches >130 mAh g-1 after the 30 cycles test, which is much better than that of PVdF. Moreover, Coulombic efficiency for charge/discharge cycles at 50 oC is effectively improved by using non-fluorine PAN-based polymer as the binder as shown in Figure 1b. A study on X-ray photoelectron spectroscopy reveals that the PAN-based binder has better coatability for active materials and conductive carbons compared with PVdF. Electrolyte decomposition at elevated temperatures is proposed to be suppressed by difference in coatability as the binder.
Together with these results, we will further discuss mechanisms of improved electrochemical properties by using non-fluorine PAN-based binders and possibility of rechargeable lithium batteries with the high-voltage positive electrode.

References

[1] K. Ariyoshi, Y. Iwakoshi, N. Nakayama, and T. Ohzuku. J. Electrochem. Soc., 151, A296 (2004).

Figure 1