bluuebunny/crossref_metadata_2025 huggingface dataset:
Polycarbonate Assisted Bi-Walled Multiscale Cathode for High-Performance Solid Oxide Fuel Cells (SOFCs) at 500 °C
Authors: Shin Sung Soo , Kim Jinhyeon , Choi Jiwoo , Lee Channyung , Kim Hyoungchul , Son Ji-Won , Shin Hyunho , Choi Mansoo
Published: February 2020

As an environmentally friendly future power source, the Solid Oxide Fuel Cells (SOFCs) have several attractive advantages such as high efficiency of direct conversion from chemical energy to electric, reduced over-potential losses and an application of non-precious metal catalyst for electrodes due to high operating temperature (> 800 °C). In contrast, this high operating temperature of SOFCs results in main issues including higher system cost and rapid cell degradation rate which limits practicality of SOFCs for commercial applications such as portable device. The most recently, the electrolyte material, Er0.4Bi1.6O3 (ESB) with exceptionally high ionic conductivity (0.027 S/cm at 500 °C) was developed to lower the operating temperature. However, their applications are limited by inter-diffusion reaction with cobalt-based perovskite catalyst such as La0.6Sr0.4CoO3-
δ (LSC), known as a conventional and highly active for materials for oxygen reduction reaction and severe weakness in reducing atmosphere.

In this study, we suggest a novel architecturing method to utilize ESB along with LSC for superior electrochemical performance. For this, we used Ce0.9Gd0.1O1.95 (CGO) and ESB as dense electrolyte and barrier electrolyte to prevent current leakage through CGO. Anode support with a thickness of 1 mm was fabricated by tape casting method. CGO and ESB were deposited on the anode support by screen printing and polymer-assisted electrospray deposition (PA-ESD) method, respectively. To achieve the compatibility of ESB with LSC, we suggested bi-walled nanotube structure cast by polycarbonate (PC) template. Ln-doped ceria (Ln: Ga or Sm) sol spread on the PC template inner surface enter into the cylindrical hole of PC due to the capillary force. After the gelation, the Ln-doped ceria sol converges to the wall surface to form a perforated cylinder. The same procedure was repeated with LSC sol, resulting in bi-walled nanotube after sintering. In this case, Ln-doped ceria not only blocks the reaction pathway between the LSC and the ESB but can lead to improved performance from extended reaction area obtained from the multiscale structure. In conclusion, our study shows that the novel architecturing method opens the possibility of expanding the range of materials selection for low-temperature SOFCs.
Electrochemical Behavior of Spinel Oxide during Magnesium Ion Insertion/Extraction Reactions at Moderate Temperature
Authors: Otani Saeko , Yamamoto Kentaro , Uchiyama Tomoki , Ichitsubo Tetsu , Uchimoto Yoshiharu
Published: February 2020

Introduction

Magnesium rechargeable batteries are deemed the next-generation secondary battery systems because of their high theoretical capacity and the terrestrial abundance of magnesium[1]. However, the Mg rechargeable battery research is still a very challenging ﬁeld. One major problem is the slow diffusion of magnesium ions in cathode materials because coulombic interaction between the carrier ion and host material is strong [2]. In this study, we examined the electrochemical performance and reaction mechanism of MgCo2O4 spinel oxide cathode [3] under moderate temperature of 150 °C, using molten salts as the electrolyte and analyzed.

Experimental

MgCo2O4 cathode material was prepared by inverse coprecipitation. The electrochemical measurement was carried out using the three-electrodes cell. The electrolyte was mixed molten salts of 10 mol% magnesium bis(trifluolomehanesulfonyl)amide (Mg(TFSA)2) and 90 mol% CsTFSA. The composite cathode was prepared from a paste by mixing 80 wt% of as-prepared active materials, 10 wt% of acetylene black (as conductive agents) and 10 wt% of polyvinylidene difluoride (binder) in 1-methyl-2-pyrrolidone solvent and then this paste was coated on the Al foil collector. A Mg ribbon was used as the anode. The reference electrode was a Li ribbon immersed in a 0.5 M LiTFSA/N, N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium bis(triﬂuoromethanesulfonyl)amide electrolyte in a glass tube separated with a porous ceramic ﬁlter. Galvanostatic charge/discharge measurements were performed at 150 °C in the Ar-filled glove box.

Results and Discussion

The prepared MgCo2O4 was a single phase and the particle size was a few micrometers, which were confirmed by X-ray diffraction and scanning electron microscopy. The MgCo2O4 cathode exhibited about 250 mAh g-1 discharge capacity and about 120 mAh g-1 charge capacity during the 1st cycling at the C/10 rate. This material shows high capacity as the cathode for Mg rechargeable batteries at moderate temperature and the reaction mechanism will be discussed in the presentation.

References:

[1]D. Aurbach., Z. Lu, A. Schechter, Y. Gofer, H. Gizbar, R. Turgeman, Y. Cohen, M. Moshkovich and E. Levi, Nature
2000, 407, 724.

[2] E. Levi, M. D. Levi, O. Chasid and D. Aurbach, J. Electroceram.
2009, 22, 13.

[3] S. Okamoto, T. Ichitsubo, T. Kawaguchi, Y. Kumagai, F. Oba, S.Yagi, K. Shimokawa, N. Goto, T. Doi, and E. Matsubara, Adv. Sci.
2015, 2, 1500072.

Acknowledgement:

This research was financially supported by the Japan Science and Technology Agency (JST), Advanced Low Carbon Technology Research and Development Program (ALCA), Specially Promoted Research for Innovative Next Generation Batteries (SPRING) Project.
Design and Development of Advanced Air-Cathodes for Li-Air Battery
Authors: Wu James J.
Published: February 2020

NASA’s future missions demand high energy density batteries. Current state-of-the-art lithium-ion batteries (LIBs) reach the specific energy capacity limits (<250 Wh/kg), thus new electrochemical storage technologies are needed to meet NASA’s future mission requirement of >400 Wh/kg. Battery chemistries with higher theoretical energy densities in particular, Li-metal based battery chemistries such as Li-air, are being actively pursued, but there remains a number of issues to be solved. Development of advanced and optimized air cathodes will be crucial for improving capacity retention and cycle life of Li-air battery. The microstructure of carbon substrates and the catalytic oxygen reduction of the air-cathode play critical roles in the electrochemical performance in Li-air batteries. With the development and proper design of air cathodes, the energy efficiency and energy density can be enhanced significantly.

In this presentation, the results of advanced permeable air cathodes design with different substrates such as 2D carbon paper or carbon cloth, vs. 3D graphene or metal foam, different high surface area carbon materials and incorporation with catalysts on oxygen reduction reactions, different porosity controlling of air cathode as well the additives in electrolyte will be presented. The cycling and rate capability performance of these air-cathodes in the Li-air cells will be discussed as well.
Towards Better Aqueous Zn Batteries: Through in-Depth Understanding and Cathode Host Development
Authors: Kundu Dipan , Oberholzer Pascal , Glaros Christos , Glatz Hadrien
Published: February 2020

Aqueous reversible zinc batteries using near-neutral aqueous electrolytes like ZnSO4/H2O are the cheaper, safer and more durable alternatives to typical nonaqueous Li-ion batteries, and seem more suited for renewable and large-scale energy storage. Yet their advancement is hindered by a limited choice of positive host materials due to sluggish solid-state diffusion of divalent zinc ions inside most inorganic structures. Much work has focused on layered and tunneled transition metal oxides with large interstitial sites or open interlayer galleries for high capacity and high rate Zn2+ storage. While these oxides deliver attractive electrochemical performance, formation/disappearance of an insulating side product - Zn4SO4(OH)6·nH2O – during battery discharge/charge has been noted for many of them. The insulating byproduct may not only be detrimental to power capability and extended cycling, its origin has been linked to parasitic side reactions involving metal dissolution and consequent increase of the electrolyte pH. An unequivocal understanding of its reversible appearance is missing, however. This presentation will delve into this topic, conveying a comprehensive mechanism that leads to the hydroxysulfate (Zn4SO4(OH)6·nH2O) formation/decomposition during zinc battery cycling, and demonstrate strategies to inhibit it. In addition, this presentation will cover our work on novel organic hosts, which owing to their malleable crystal structure provide facile and reversible Zn2+ storage. Operando X-ray diffraction, electron microscopy, and impedance analysis have been applied together with theoretical calculations to elucidate the Zn2+ storage mechanism. The deeper understanding gained has been channeled to tune the cathode design towards stable electrochemical cycling
Click Reaction Assisted By Cu Electro-Oxidation
Authors: Carre-Rangel Luceldi , Oropeza-Guzman Mercedes Teresita , Rivero Ignacio Alfredo
Published: February 2020

The click chemistry is a green, selective, qualitative, pH-sensitive and economical approach, suitable characteristics for use in the synthesis of a variety of bioconjugates including peptides, proteins, polysaccharides, etc. The purpose of the click chemistry reactions is to bind two molecular building blocks, selectively and under mild reaction conditions, obtaining high yields, generating only harmless byproducts of reaction and easy to separate by non-chromatographic methods.

In 2002, Sharpless's research group reported the 1,3-dipolar Copper catalyzed Alkyne Azide Cycloaddition (CuAAC) reaction, which is regioselective for the formation of 1,4-disubstituted triazoles, becoming the best known click reaction.The reaction is carried out at room temperature and has high conversions at shorter times, compared to the uncatalyzed (not regioselective) cycloaddition reported by Huisgen in 1963. Other strategies have been reported to perform the cycloaddition of alkynes and azides without the use of a copper catalyst, however, for these reactions the kinetics are slow and do not present regioselectivity. Hence, the process catalyzed by copper is still preferred.

Intending to improve the green chemistry procedure to synthesize triazoles, considering that electrons as redox reactants instead of polluting reducing/oxidizing reagents, it is propose to assist a conventional click reaction by electrochemical methods. Since a metallic species as Cu is relatively easy to oxidize by an electrolysis, the main objective is to generate ionic species of Cu as Cu+1 serving to catalyze the click reaction. For this purpose a suitable electrolytic media as well as a proper electrochemical cell configuration (Cu-working electrode, Ag/AgCl/Cl-
(tert-butylalcohol/water) reference electrode and Pt-counter electrode) were used to test the reaction improvement by the in-situ electro-oxidation of Cu.

The synthesis of 1-benzyl-4-phenyl-1H-1,2,3-triazole, 3-(1-benzyl-1H-1,2,3-triazol-4-yl)phenol and 1-benzyl-4-(naphthalen-1-yl)-1H-1,2,3-triazole derivatives via the in-situ preparation of Cu+1 by an electrochemical process, was very efficient, safe and inexpensive, since catalyst was obtained under soft conditions reaction generating extremely small amounts of electrooxidized Cu (~4.3x10-3 mol in one hour).

Conventional and electrochemical methods were compared, the last method yielded 78-90% in one hour of reaction and the conventional method produced only 56-60% at the same time, therefore, the electro-Click reaction is faster and more efficient.
Single Synaptic Observation of Cholinergic Neurotransmission on Living Neurons: Concentration and Dynamics
Authors: Shen Mei
Published: February 2020

Acetylcholine, the first neurotransmitter identified in 1914, plays key role in human health and its defects have been associated with neurodegeneration. Elucidating its release dynamics and concentration profiles at the source of its release, the synaptic cleft, is instrumental in understanding neurodegenerative diseases. Here we present our study of acetylcholine synaptic release with a nanoITIES electrode of ~15 nm in radius, unveiling unprecedented details on its release dynamics and concentration profiles around single synaptic cleft. We employed nanoresolved scanning electrochemical microscope (SECM) (1-4) to position the nanoelectrode around the synaptic cleft. We further demonstrate the quantification of acetylcholine single exocytotic events from Aplysia californica neuron cells using a nanoITIES pipet electrode. Development of nanoITIES electrodes for non-redox active transmitter detection will be presented as well. (5-8)

Acknowledgement: This research was supported by the National Institute Neurological Disorders and Stroke of National Institutes of Health under Award Number R21NS085665.

1. Q. Chen, L. Luo, H. Faraji, S. W. Feldberg, H. S. White, J. Phys. Chem. Lett. 2014,
5
, 3539-3544.

2. Shen, R. Ishimatsu, J. Kim, S. Amemiya, J.
Am. Chem. Soc. 2012,
134
, 9856–9859.

3. A. J. Bard, M. V. Mirkin, Ed., Scanning Electrochemical Microscopy (CRC Press/Taylor & Francis: Boca Raton, FL, ed. 2, 2012).

4. T. Sun, Y. Yu, B. J. Zacher, M. V. Mirkin, Angew. Chem. Int.
Ed. 2014,
53
, 1-6.

5. Shen, M.; Colombo, M. L. Analytical Methods, 2015,
7
, 7095-7105.

6. Colombo, M. L.; Sweedler, J. V.; Shen, M. Chem. 2015,
87
, 5095-5100.

7. Colombo, M. L.; McNeil, S.; Iwai, N.; Chang, A.; Shen, M. Journal of The Electrochemical Society, 2016,
163
, H3072-H3076.

8. Iwai, N. T.; Kramaric, M.; Crabbe, D.; Wei, Y.; Chen, R.; Shen, M. Chem. 2018,
90
, 3067-3072.
Monitoring Electrolyte Degradation in Electrochemical Machining Operations
Authors: Humiston Elaine M. , Humiston Christopher J. , Carter Joseph , Maurer Joshua A.
Published: February 2020

Electrochemical machining allows for the rapid processing of complex geometries on difficult to machine materials. However, over time electrolyte performance degrades and impacts the metal removal rate which impacts finished machined geometry. We have evaluated electrolyte degradation to develop methods to monitor and control electrolyte composition for electrochemical machining processes. Electrolytes containing sodium nitrate, sodium chloride, and mixtures of the two were evaluated during the machining of 4340 steel. Linear sweep voltammetry methods have been developed to monitor changes in electrolytes as a function of machining time. These changes have been correlated with composition, pH, and conductivity of the electrolyte and the surface finish and material removal rate to understand the general health of the electrolyte throughout the machining process. The methodology allows for electrolyte recycling and replenishment during large scale machining.
Photocatalyst on the Surface Flexible Atmospheric Pressure Plasma Wire Electrodes
Authors: Eum Kyong Yong , Yoon Choong Sup , Ko Jang Myoun
Published: February 2020

The purpose of this study is to improve the physical properties of photocatalyst ceramic coatings on flexible plasma electrodes in order to improve the decomposition efficiency of harmful gas. TiO2, ZrO2, and ZrOH were used as the photocatalyst materials, TSR116 was used as a flexible silicone binder, and Xylene was used as a dispersing agent. As the ratio of TSR116 increased, the surface adhesion and crack resistance improved, but the photocatalyst material exposed to the surface decreased. Increasing the xylene ratio as a diluent to adjust the ratio of TSR116 increased the exposure of the photocatalyst on the surface but resulted in poor adhesion and surface cracking. The surface uniformity and cracking of the varying ratios of TSR116, xylene, and TiO2 were analyzed by scanning electron microscopy. High surface uniformity was found to improve the stability and efficiency of the surface of flexible plasma electrodes.
Electrodeposition of Si in Molten CaCl2 Above 1300K
Authors: Takenaka Toshihide , Shimokawa Ryoya , Okada Haruka , Morishige Taiki
Published: February 2020

Metallic Si is produced by carbon reduction of SiO2 in an arc furnace above 2000K, and the energy consumption and CO2 exhaustion in the process are very large. The authors reported that TiO2 could dissolve in molten CaCl2 containing CaO above 1300K, and that Ti metal was electrodeposited in the bath. This result implies the possibility of electrolytic production of liquid metallic Si in molten CaCl2-CaO-SiO2 above its melting point, which can lead the innovative production process of metallic Si with lower energy consumption and lower CO2 exhaustion. To realize this process, the electrochemical behavior of Si in molten CaCl2-CaO-SiO2 at a very high temperature has to be studied in detail. In this study, the cathodic reaction has been investigated in molten CaCl2-CaSiO3 above 1300K, and the electrodesipotion of metallic Si has been attempted.

Based on our previous studies on Ti electrolysis, calcium silicate was used instead of CaO and SiO2. Calcium chloride containing 0~10 mol% CaSiO3 in a Mo crucible was fused in an air-tight furnace, and electrolysis was carried out at 1373 ~ 1573 K under a pure Ar flow. The working electrode was mainly a Mo wire with an Al2O3 sheath, and a SiC rod was also used. Another Mo wire electrode was used as quasi-reference electrode, and its potential was calibrated with Mo dissolution potential in the bath. Cyclic voltammetry was performed to investigate the electrode reactions in the bath, and then potentio-static electrolysis was carried out to obtain electrodeposit. The electrode surfaces after electrolysis as well as the electrodeposit were analyzed by XRD and SEM-EDX.

The cathodic current obviously enlarged with the CaSiO3 addition, and the CaSiO3 solubility seemed to increase with the bath temperature. A sharp cathodic current peak appeared around -1.1 V (vs. Mo dissolution potential) at the Mo electrode, while no cathodic current peak was observed at the SiC electrode. Electrodeposit as shown in Fig.1 was obtained at the Mo electrode, and metallic Si was detected in it. Although a MoSi2 layer was also formed on the surface by electrolysis as shown in Fig. 2, the amount of Si in the layer was limited considering the quantity of electricity during the electrolysis. Since CaSi2 was sometimes found in the deposit, the suitable electrolytic potential needs to be revealed.

It was shown that metallic Si was obtained by electrolysis in molten CaCl2-CaSiO3 under the proper condition. However, the amount of metallic Si on the electrode could not be determined yet because of the powdery morphology of deposit. It should be desirable to obtain liquid metallic Si by electrolysis above its melting point.

Figure 1
Gadolinium Electrochemical Deposition Targeting Neutron Phase Contrast Imagin
Authors: St. John Christopher R. , Pillars Jamin R. , Amber Dagel L , Jau Yuan-Yu , Arrington Christian L.
Published: February 2020

Neutron Phase contract imaging (NPCI) is a promising technique for non-destructive imaging of large scale (meter to 10 meters in size) and thick (cm-100’s cm cross section) metal components to characterize internal structure and ensure reliability of the build. Thermal neutron penetration depth through metals is far superior compared to x-rays and offers the ability to modify the neutron to provide more or less interaction with the intended sample. One possible application is imaging of additively manufactured metals using NPCI to characterize internal porosity and defects that might arise in selective laser sintering additive manufacturing. NPCI requires High Aspect Ratio (>10:1) gratings with feature sizes around 2 µm made of high neutron absorbing materials—with gadolinium the preferred metal of choice. Current fabrication methods etch trenches in silicon and fill them with gadolinium powder/epoxy [1] or a thin metal deposition of gadolinium [2] creating a gadolinium grating. The challenge in electroplating gadolinium is in finding compatibility between the chemistry and the downstream microfabrication techniques using grating molds sensitive to heat and chemical processes. Gadolinium salts were mixed with sulfamate-based aqueous solutions, deep eutectic solvents, and organic solvents. Gadolinium deposition windows were found using cyclic voltammetry experiments and deposited films were characterized for feasibility and make-up using scanning electron microscopy, energy dispersive spectroscopy, and confocal microscopy. Chemistry efficiencies and expected lifetimes were analyzed over multiple weeks duration. Microfabrication compatibility studies were then used to find the appropriate matching template grating mold for uniformly coating the gadolinium onto the grating in future work.

Kim, J., et al., Fabrication and characterization of the source grating for visibility improvement of neutron phase imaging with gratings. Review of Scientific Instruments, 2013. 84(6).

Grunzweig, C., et al., Design, fabrication, and characterization of diffraction gratings for neutron phase contrast imaging. Review of Scientific Instruments, 2008. 79(5).

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA-0003525. The views expressed in the article do not necessarily represent the views of the U.S. Department of Energy or the United States Government.
Electrochemical and Spectroscopic Insight into the Interfacial Structure of Ionic Liquids
Authors: Klein Jeffrey Michael , Gurkan Burcu
Published: February 2020

Supercapacitors, or electrical double layer capacitors, are energy storage devices that offer higher power when compared to batteries. EDLCs are ideal for applications that can utilize a fast charge/discharge cycle and require long cycle lifetimes and are used in electronics, home appliances, and in some large-scale energy regeneration for automobiles and industrial equipment. Charge is stored in an EDLC by the accumulation of ions in the electrode-electrolyte interface. Aqueous and organic based systems create a well understood structure of accumulated ions where solvated ions pack into the interface and balance the charge of the electrode. Ionic liquids are a new class of electrolyte being considered for application in EDLCs. Ionic liquids are composed only of ions and do not form a structure at the interface that is readily understood. In order to successfully utilize Ionic Liquids for energy storage such as with supercapacitors, the structure of ion accumulation must be understood at a fundamental level. We investigated the structure of the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, [EMIM][TFSI], on two different electrodes and quantified the interfacial rearrangement thereby opening the door to begin a rational study of the interface through modification of the ionic liquid.

Differential capacitance of [EMIM][TFSI] on glassy carbon and silver electrodes has been measured by electrochemical impedance spectroscopy (EIS). The interfacial rearrangement was further characterized using electrochemical surface enhanced Raman spectroscopy (SERS). Potential dependence of the differential capacitance demonstrates the camel-like structure indicating formation and collapse of ion structure in the interfacial layer. The EIS data suggest that the formation of the structure occurs through multiple processes which change as the capacitance maximum is approached. On the silver electrode distinct shifts in the vibrational energies of the interface are shown via SERS to occur as the cell potential is forced away from open circuit potential which is associated with local changes in polarizability of molecular interactions associated with the interfacial structure. The series of techniques presented in this work open the path for different ionic liquids to be studied.
Ionic Liquids for Controlled Synthesis of Functional Materials for Energy-Related Applications
Authors: Dai Sheng
Published: February 2020

The conventional synthesis of functional materials relies heavily on water and organic solvents. Alternatively, the synthesis of functional materials using or in the presence of ionic liquids represents a burgeoning direction in materials chemistry.1-4 Ionic liquids are a family of non-conventional molten salts that can act as both templates and precursors to functional materials, as well as solvents. They offer many advantages, such as negligible vapor pressures, wide liquidus ranges, good thermal stability, tunable solubility of both organic and inorganic molecules, and much synthesis flexibility. The unique solvation environment of these ionic liquids provides new reaction media for controlling formation of porous materials, creating functional groups in biphasic media, and tailoring morphologies of advanced materials. Challenges and opportunities in using ionic liquids for synthesizing functional materials in energy-related applications will be discussed.

Acknowledgment: This work was conducted at the Oak Ridge National Laboratory and supported by the Office of Basic Energy Sciences, U.S. Department of Energy, under contract No. DE-AC05-00OR22725 with UT-Battelle, LLC.

References

(1) Ma, Z.; Yu, J. H.; Dai, S. Preparation of Inorganic Materials Using Ionic Liquids. Adv. Mater.
2010, 22, 261-285.

(2) Sun, X. Q.; Luo, H. M.; Dai, S. Ionic Liquids-Based Extraction: A Promising Strategy for the Advanced Nuclear Fuel Cycle. Chem. Rev.
2012, 112, 2100–2128.

(3) Huang, K.; Chen, F. F.; Tao, D. J.; Dai, S. Ionic liquid-formulated hybrid solvents for CO2 capture. Curr. Opin. Green Sustain. Chem.
2017, 5, 67-73.

(4) Yang, Q. W.; Zhang, Z. Q.; Sun, X. G.; Hu, Y. S.; Xing, H. B.; Sheng Dai, S. Ionic liquids and derived materials for lithium and sodium batteries. Chem. Soc. Rev.
2018, 47, 2020-2064.
Electrochemical Formation of Dy-Fe and Nd-Fe Alloys in Molten CaCl2-LiCl Systems
Authors: Konishi Hirokazu , Hua Hang , Ono Hideki , Koizumi Yuichiro , Oishi Tetsuo , Nohira Toshiyuki
Published: February 2020

We proposed a new separation and recovery process for rare earth (RE) metals from scraps using molten salt and an alloy diaphragm. RE containing scrap is used as the anode. A RE-transition metal (TM) alloy is used as the diaphragm, which functions as a bipolar electrode. During electrolysis, all the RE metals in the anode are dissolved in the molten salt as RE ions. One or several specific RE ions are selectively reduced to form RE-TM alloys on the alloy diaphragm according to their formation potentials and/or alloying rates. Subsequently, the RE atoms chemically diffuse through the alloy diaphragm and are dissolved into the molten salt as RE ions in the cathode room. The permeated RE ions are finally deposited on the Mo or Fe cathode as RE metals. The RE ions remaining in the anode room can be collected by electrolysis using another cathode in the anode room. Almost all impurities remain in the anode room as residue or anode slime.

The present study focused on Fe alloys as alloy diaphragms. The electrochemical formation of Dy-Fe and Nd-Fe alloys in molten CaCl2-LiCl systems at 873-973 K. To confirm the formation of Dy-Fe alloys, potentiostatic electrolysis was conducted at 0.30 V(vs. Li+/Li) and 0.50 V for 1 h using Fe plate cathodes at 873 K in CaCl2-LiCl-DyCl3 (0.50 mol% added). The two samples were analyzed by XRD. The alloy phases were identified as DyFe2 or DyFe3. On the other hand, potentiostatic electrolysis was conducted at 0.30 V and 0.50 V for 1 h using Fe plate cathodes at 873 K in CaCl2-LiCl-NdCl3 (0.50 mol% added). From the result of XRD analysis, it was found that several Nd-Fe phases were formed.
Effects of Introducing Metal Adatoms on the Electrochemical CO2 Reduction Behavior of Copper
Authors: Nishimura Yusaku F , Chan Karen , Hahn Christopher , Jaramillo Thomas F
Published: February 2020

The electrochemical CO2 reduction reaction (CO2RR) is considered as a promising candidate for a carbon negative technology to realize ecological and economical sustainable development. At present, copper is the only metal that can produce fuels (hydrocarbons and oxygenates) through CO2RR, but has many key scientific challenges remaining for implementation as an electrocatalyst (especially, selectivity and activity). One of the common strategies to tune electrocatalytic properties is tailoring active sites in an electrocatalyst by introducing another metal to one metal surface. In this work, we investigated the effect of introducing another metal M onto Cu(100) on the CO2RR.

Physical vapor deposition was performed to obtain a 100-nm Cu(100) film epitaxially grown onto Si(100) substrate, followed by introducing 1-Å-equivalent another metal M (M: Ag, Au, In, Mo, Ni, Pd, and Sn) atoms onto the Cu(100) surface in vacuum. Atomic force microscopy and X-ray photoelectron spectroscopy guaranteed that M certainly existed on Cu and the M/Cu electrocatalyst had a smooth surface whose roughness was ±2 nm. The M/Cu electrocatalyst was supplied to a series of 15-min electrolysis in 0.1 mol dm−3 KHCO3 aqueous solution at potentials ranging from −0.6 to −1.1 V with respect to reversible hydrogen electrode at pH 6.8. Gaseous and liquid products were quantified with gas chromatography and nuclear magnetic resonance, respectively.

A series of electrocatalytic evaluation pointed out the following general trends concerning the electrocatalytic properties of the M/Cu bimetallic thin films for CO2RR. For selectivity, the M atoms introduced to Cu(100) surface vary the Faradaic efficiency for each product to decrease average number of electrons transferred to a CO2 molecule. For activity, the introduction of M atoms onto Cu(100) surface suppresses the production rates for both C1 and C2+ products although it increases or decreases the total current density as seen in cyclic voltammetry, depending on M. The aforementioned experimental facts suggest the role of M that the M atoms introduce onto Cu(100) surface seem to cause some bimetallic effects on the CO2RR selectivity of Cu as well as an inhibition effect on the CO2RR activity of Cu. Electron-transfer reaction kinetics are further studied via a combined experiment and theory approach to discuss the nature of active sites in M/Cu bimetallic systems and the role of M in determining product distribution, which will be explained in the conference.
Metal Nitrides for Electrochemical Ammonia Synthesis in Molten Salts
Authors: Sudmeier Tim , McPherson Ian James , Fellowes Joshua , Tsang Shik Chi Edman
Published: February 2020

Ammonia is one of the most important base chemicals in the world being a quintessential ingredient in most fertilizers. It is produced on the mega ton per year scale by the Haber-Bosch process from hydrogen and nitrogen at temperatures of around 400-500°C and pressures of up to 200 atmospheres contributing approximately 2% to global CO2 emissions.1 A promising alternative for small scale applications is electrochemical ammonia production utilizing molten salts as electrolytes.2 Such systems work at ambient pressure, moderate temperature and use renewable hydrogen sources like water enabling small local production of ammonia for energy storage and as building block chemical for fertilizer synthesis.2

Few materials have been evaluated as electrocatalysts for ammonia synthesis in molten salts, mainly transition metals.2Metal nitrides, especially Co3Mo3N, are highly active in classical ammonia synthesis with a Mars-van-Krevelen-type mechanism being suggested as the mechanism at play.3 Recently, computational studies have suggested using metal nitrides as electrocatalysts for ammonia formation assuming a similar mechanism.4

In this work, we explore the possibilities of using more complex gas electrode materials in alkali chloride melt to increase the rate and current efficiency of electrochemical ammonia synthesis. Furthermore, we hope to gain a deeper understanding of the mechanism of nitrogen reduction and more generally ammonia formation in molten salts. We synthesized several ternary metal nitrides using temperature-programmed nitridation of oxide precursor and characterized them by powder XRD, BET, XPS, UV-Vis, SEM, TEM and SQUID. Furthermore, the stability of the nitride phase in the chloride melt was tested and the necessary conditions to inhibit decomposition were optimized. A range of electrochemical tests (CV, amperometry, etc.) were carried out and XPS, as well as SEM were used to monitor compositional and structural changes on the surface. Finally, metal nitride electrodes were used for nitrogen reduction.

Lan, R.; Irvine, J. T. S.; Tao, S.Sci. Rep.
2013, 3.

Giddey, S.; Badwal, S. P. S.; Kulkarni, A. Int. J. Hydrogen Energy
2013, 38 (34), 14576.

Abghoui, Y.; Skúlasson, E. Procedia Computer Science
2015, 51, 1897.

Howalt, J. G.; Vegge, T. Phys. Chem. Chem. Phys.
2013, 15 (48), 20957.
Investigation of Graphene Supported Au-Cu Nanoparticles As Electrocatalyst for CO2 Electro-Reduction
Authors: Balčiūnaitė Aldona , Rutkauskas Andrius , Tamašauskaitė-Tamašiūnaitė Loreta , Norkus Eugenijus
Published: February 2020

Carbon dioxide (CO2) is the most common greenhouse gas in our planet. Reduction of CO2 production and conversion of CO2 into useful materials at the same time is necessary. CO2 conversion using electro-catalysis can be controlled by electrode potentials and the reaction temperature. Also the electrochemical reaction systems are compact, modular and easy for scale-up applications. Cu-based composites with different compositions can seriously influence its electrocatalytic performance toward CO2 reduction reaction.

In the present study, a rapid microwave heating method was used to prepare the graphene or carbon supported Au-Cu nanoparticles as electrocatalysts for the electrochemical reduction of CO2. The morphology and composition of the fabricated catalysts were examined using Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The activity of the fabricated catalysts for CO2 electro-reduction was examined using cyclic voltammetry and linear sweep voltammetry in acidic (pH=1.7), neutral (pH=6.3) and alkaline (pH=10.3) media.

It was found that the graphene or carbon supported Au-Cu catalysts show a similar electrocatalytic activity for the electro-reduction of CO2 in the acidic media, whereas the graphene supported Au-Cu catalyst shows a higher activity in the neutral and alkaline media as compared with that of carbon supported Au-Cu catalyst.
(Invited) Highly Conductive Polymers and Their Applications for Energy Conversion
Authors: Ouyang Jianyong
Published: February 2020

Although intrinsically conductive polymers were discovered in 1970s, their application is quite limited mainly due to their poor processability and low conductivity. Most of conductive polymers are insoluble in any solvent and cannot melt. Poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) has gained great attention and considered as the most successful conductive polymer, because it can be dispersed in water and some polar organic solvents. But it has a problem of low conductivity. The as-prepared PEDOT:PSS films from its aqueous solution usually has a conductivity of less than 1 S/cm. Here, I will present several novel methods to significantly enhance the conductivity of PEDOT:PSS. The conductivity can be enhanced to be more than 3000 S/cm. Thus, highly conductive PEDOT:PSS can be used as the transparent electrode of optoelectronic devices like solar cells because it can have high transparency in the visible range. In addition, they can exhibit high thermoelectric properties.
Development of an Electrochemical Sensor for the Detection of Dopamine Based on PEDOT and Silver Nanoparticles
Authors: Lucero Gisella Liliana , Gruia Violeta-Tincuta , Ispas Adriana , Bund Andreas
Published: February 2020

Dopamine is an organic compound that plays a crucial role in many brain processes. Several neurological and neuropsychiatric disorders are associated to the deficiency of dopamine and for that reason the detection of this compound is a major concern. Poly(3,4-ethylenedioxythiophene) (PEDOT) is a conducting polymer whose properties depend on the method used for its deposition and of the counterions included in its structure during the deposition process. This polymer has been used with different dopants for the detection of many organic and inorganic compounds. Furthermore, nanostructures such as carbon nanotubes, metal oxides, reduced graphene oxide and metal particles have been used for the detection of dopamine [1,2].

In this work electrodeposition of PEDOT was carried out by scanning the working electrode (glassy carbon) potential between -0.3 and 1.1 V vs Ag/AgCl 3.5 M at 50 mV/s. After the electrodeposition, the films were reduced at -0.3 V for 10 minutes and then silver nanoparticles were deposited on the films at open circuit potential for 30 minutes. The morphology of the PEDOT/ClO4 films with and without SDS modified with silver particles was analyzed by SEM. The nanoparticles are seen as bright spots in the SEM images. In both films there are isolated and conglomerated nanoparticles. In the PEDOT/ClO4 films the nanoparticles are distributed mainly in the globules while in the PEDOT/ClO4/SDS films silver nanoparticles are also placed a greater depth in the porous structure. The size of the nanoparticles in the PEDOT/ClO4/SDS films is between 6 and 100 nm. The elemental composition of the modified electrodes was determined by EDX. The spectrums of PEDOT/ClO4 films with and without SDS modified with silver nanoparticles confirmed the presence of carbon, sulfur and oxygen, the constituents of PEDOT in the films. In addition, the spectrums also showed the peak for silver which proves that silver nanoparticles were incorporated into the PEDOT films.

The prepared structures differ from films prepared in previous reports and exhibit a different electrochemical behavior [3,4]. The analytical performance of PEDOT/ClO4/SDS modified with the nanoparticles for the detection of dopamine was evaluated by differential pulse voltammetry. The sensitivity of the sensor was 0.03 +/-0.01 µA µM-1.

[1] K. Liu, H. Pang, J. Zhang, H. Huang, Qing L. and Y. Chua. RSC Adv.4 (2014) 8415.

[2] C. L. Weaver H. Li, X. Luod and X. T. Cui. J. Mater. Chem. B. 2 (2014) 5209.

[3] V. Karabozhikova and V. Tsakova. Chem. Pap. 71 (2017) 339.

[4] E. Tolstopyatova, N. Pogulyaichenko, and V. Kondratiev. Russ J. Electrochem. 50 (2014) 510

Figure 1
Sensitive Determination of Mefenamic Acid in Biological Fluids and Pharmaceutical Formulations on Carbon Nanotubes Fabricated Sensor
Authors: Tarlekar Pravin , Chatterjee Sanghamitra
Published: February 2020

Mefenamic acid (MFA) is a member of fenamate group of non- steroidal anti-inflammatory drug used in the therapy of pain phenomena and blockade of inflammatory areas; for the stimulation of the immune system in patients with arthritis and arthrosis. The degree of menstrual blood loss is reduced with the treatment of MFA and it is also used to treat autoimmune haemolytic anaemia. Measurement of plasma levels of MFA may provide valuable information for MFA treatment in premature infants with symptomatic patent ductus arteriosus and for preventing possible toxic effects. However, the excessive intake of MFA leads to diarrhoea, vomiting, lactic acidosis, hepatic necrosis, liver injury, morbidity and mortality in humans. Consequently, the development of an inexpensive, sensitive and accurate analytical method for determination of MFA is of considerable importance.

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most commonly prescribed agents worldwide due to their anti-inflammatory, antipyretic and analgesic properties and are usually used in the treatment of inflammatory and degenerative diseases of the articulations. In addition, epidemiological studies have shown that long-term use of NSAIDs reduces the risk of developing Alzheimer disease and delays its onset. This category of drugs alleviate pain by counteracting the cyclooxygenase (COX) enzyme. On its own, COX enzyme synthesizes prostaglandins, creating inflammation. In whole, the NSAIDs prevent the prostaglandins from ever being synthesized, which otherwise lead to an increase of vascular permeability, edema, hyperalgesia, pyrexia, and inflammation. These drugs have also shown to induce various forms of adverse drug reactions, including adverse gastrointestinal effects, renal dysfunction and nephrotoxicity, liver damage, adverse neurological effects, and rhabdomyolysis.

Herein, we report the selective and sensitive determination of mefenamic acid on single walled carbon nanotubes modified glassy carbon electrode (GCE) employing square wave voltammetry. The developed sensor exhibited amelioration in the peak current response with a negative shift in the peak potential in comparison to multi walled carbon nanotubes modified GCE and bare GCE. Voltammetric studies indicated the oxidation of MFA at the electrode surface through a one electron and one proton irreversible step and fundamentally controlled by adsorption. A good linear relationship has been found between the anodic peak current and mefenamic acid concentration in the range of 0.1 – 35 µM with limits of quantification and detection as 44.7 and 13.4 nM, respectively. The interfering effect of physiologically common interferents on the current response of mefenamic acid has been reported. Furthermore, the proposed method was successfully applied to the determination of mefenamic acid in pharmaceutical formulations and human plasma samples.
Electrochemical Techniques for Real Time, in-Situ Monitoring of Biogeochemistry
Authors: Satjaritanun Pongsarun , Shimpalee Sirivatch , Weidner John W. , Devivo Blake A. , Turick Charles E. , Colon-Mercado Hector , Greenway Scott , Martin Ariane L. , Henson J M.
Published: February 2020

Microorganisms exert an enormous influence on the biogeochemical cycling of minerals and on the detoxification of subsurface contaminants. The capacity of microbes to transfer electrons extracellularly provides them with tremendous opportunities to alter the geochemistry. These microbial electrochemical processes also provide technical opportunities to study phenomena related to biogeochemical change, especially environmental clean-up of inorganic contaminants in the subsurface. By regarding bacteria as small electronic circuits we could monitor changes in their physiological status through electrochemical techniques. A flat patterned electrode positioned in-situ provided a versatile design that accommodated numerous electrochemical techniques including electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Changes in phase shift, relative real permittivity and imaginary conductivity were monitored and provided valuable real time, in-situ information regarding microbial dynamics. Microbial redox interactions were also followed by monitoring low frequency phase shifts in the subsurface environment. These techniques correlated impedance parameters to specific biogeochemical and physiological processes that allowed us to evaluate biogeochemical activity, especially related to the growth dynamics of microorganisms. Our approach of incorporating electrochemical techniques, especially EIS and CV has enormous potential to provide valuable information about changes in subsurface microbial activity and contaminant behavior in-situ. Figure 1 shows examples of cellobiose conversion to acetate and voltammograms of C. phytofermentans during growth. This information can be used to direct subsurface sampling activities and be used in conjuction with data from conventional sampling to provide information about subsurface activity and dynamics.

Figure 1
Early Diagnosis of Diabetes Using Stochastic Sensors
Authors: Stefan-van Staden Raluca-Ioana
Published: February 2020

Diabetes is one of the most frequent diseases, affecting 1 in 12 persons worldwide according to International Diabetes Federation, therefore improved methods of monitoring and screening are needed.

Stochastic sensors represent a promising candidate in early diagnosis due to their capacity to perform qualitative and quantitative analysis of multiple biomarkers.

For the determination of C-peptide, insulin, proinsulin, leptin, adiponectin and CRP the immunoassay techniques are routinely used in clinical practice, requiring diferite detection kits, therefore one of the main advantage in using this method consists in determining in one run all the analytes.

In this paper, stochastic microsensors based on new carbon materials were proposed for the assay of diabetes related biomarkers like: proinsulin, insulin, C-peptide, leptin, adiponectin, Zn, pyruvic and lactic acids and CRP in biological fluids like urine and serum samples.
Visualization of Potential Distribution inside Crevice of Type 430 and 304 Stainless Steels
Authors: Takaya Natsumi , Muto Izumi , Sugawara Yu
Published: February 2020

Stainless steels are widely used in industries because of their high anti-corrosive performance due to their passivation ability. However, crevice corrosion sometimes occurs in chloride environments. It is known that crevice corrosion is initiated when electrode potential inside crevice changes from the passive to active state. Therefore, the potential is the important factor to understand the mechanism of crevice corrosion. In this research, visualization of the potential inside the crevice for type 430 and 304 stainless steels was performed in 0.01 M NaCl at pH 3.0.

An indium-tin oxide (ITO) glass with a sensing layer was applied for visualizing the potential. In the sensing layer, a redox indicator was entrapped. Figure 1 shows the schematic illustration of apparatus for the calibration procedure for color change of the plate. The ITO glass with the sensing layer (sensing plate) was used as a working electrode. In an electrolyte, a mirror polished Pt plate was put below the sensing plate to reflect the image of the sensing plate, and the optical microscope images were taken through the sensing plate by a CCD camera system. Electrode potential of the sensing plate was changed from -0.52 to 1.08 V in 0.01 M NaCl (pH 3.0 adjusted with HCl). All potentials reported in this work refer to Ag/AgCl (3.33 M KCl).

Figure 2 shows the optical micrographs of the sensing plate placed above the Pt. It is clear that the color was changed from light green to dark blue with increasing electrode potential. The sensing plate was applied to crevice corrosion tests in 0.01 M NaCl (pH 3.0 adjusted with HCl). In the crevice corrosion tests, the sensing plate was used as a crevice former. The distributions of electrode potentials inside the crevice of the stainless steels were monitored from the color of the sensing plate.

Figure 1
Spectra Fitting of Impedance By Differential Evolution Algorithm for Galena Anodic Oxiation in Presence of Xanthate
Authors: Moreno-Medrano Edgar David
Published: February 2020

In this work, we present results for the study of the oxidation and adsorption mechanism for galena in presence of xanthate. This study was performed with impedance measurements and its spectral fitting from a mechanistic approach obtaining the transfer functions for total impedance from a reaction mechanism proposed. At our best knowledge, there are no similar studies for this system from the mechanistic point of view, although they do exist from the equivalent circuits approach. The spectra were fitted using a differential evolution algorithm (DE), which include 19 optimization parameters. All the parameters obtained from the fitting were satisfactory, since all of them have physical meaning, showing trends according to the expected; so that the fundamental kinetic information obtained for the interfacial processes for galena/xanthate system are valid. The proposed reaction mechanism includes the presence of two intermediates-adsorbed X2ads and Pb(X) 2ads, (adsorbed dixantogen and adsorbed lead xanthate, respectively) which inhibit the oxidation process of the galena surface. On the other hand, the inductive loops observed at positive polarization potentials could be associated with a process of surface relaxation due to the adsorption-desorption of the intermediates-adsorbed species.