bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrocatalytic CO2 Reduction on Nanosized Ag Dendrites Electrodeposited on Indium Doped SnO2 Electrodes Immersed in Aprotic Medium
Authors: Banda-Alemán Jorge Alberto , Sepúlveda Selene , Manríquez Juan
Published: February 2020

Electrochemical reduction of CO2 by means of metallic nanostructures (i.e. Ag, Au, Cu), sp2 carbon derivatives (i.e. graphite oxide, graphene) and their combinations is considered as a promising pathway for aiding to decrease the effects of the global warming. However, the electrochemical reduction of CO2 contained in aqueous medium requires large overpotentials with a significant competition with the H2 evolution reaction, thus resulting in low faradaic efficiencies. On the other hand, reactivity of metallic nanostructures is strongly dependent from the size and the aspect ratio in nanoparticles and nanorods, respectively, as well as from the crystalline faces exposed to the electrolytic medium. In order to overcome this trouble, we studied the electrocatalytic CO2 electroreduction in aprotic medium by employing nanosized Ag dendrites, which were previously electrodeposited on In-doped SnO2 (ITO) electrodes by means of a double-pulse potential (DPP) technique (deposition conditions were defined by means of cyclic voltammetry (CV) technique). These experiments were carried out in a three-electrode cell containing aqueous 0.1M KNO3+1mM AgNO3. In this sense, the presence of dendritic nanostructures on the silver-modified ITO electrodes (ITO/Ag) was confirmed by scanning electron microscopy. CV results showed that the electrical charge associated to the Ag dissolution is clearly dependent from the growth time (duration ~ms) and independent from the nucleation time (duration ~sec). This result demonstrated that the Ag deposition is kinetically-controlled by one-electron transfer. Furthermore, CV results demonstrated that the thermodynamic potential for the Ag reduction E°Ag+|Ag was observed at -0.32 vs. Ag|AgCl (3M NaCl) during the first scan but, it becomes less cathodic at E°Ag+|Ag= -0.08 vs. Ag|AgCl (3M NaCl) during the successive scans; thus confirming that the dendritic shape of the Ag deposits is promoted immediately after some seeds of metallic atoms are confined on the ITO surface. Complementarily, electrochemical CO2 reduction in a three-electrode cell containing propylene carbonate + 0.1M Bu4NPF6 was confirmed on the as-prepared ITO/Ag electrodes by means of linear voltammetry (LV). In this way, two reduction peaks were localized at -0.3 and -0.5V vs. Ag|AgCl (0.01M AgNO3 + 0.1M Bu4NCl in MeCN), which can be associated to the semireactions 1 and 3, respectively. Electrochemical contribution from the ITO substrate was absent during the CO2 reduction reaction.

(1)        CO2 + e- → CO2
·
-
(slow)

(2)        CO2 + CO2
·
-
→ (CO2)2
·
-

(3)        (CO2)2
·
-
+ e- → -OOC-COO·
-
Catalysts for the Electrochemical Conversion of Carbon Dioxide
Authors: Billy Joshua , Co Anne
Published: February 2020

Currently, there are no large, commercial processes that convert carbon dioxide back to useful chemicals, save for the water-gas shift that leads to the Fischer-Tropsch process, but both of these reactions require a large amount of energy input. Simpler methods exist, such as the electrochemical conversion of carbon dioxide, which can be performed in aqueous solution at room temperature1. This carbon dioxide utilization pathway is not yet fully developed for several reasons: lack of a selective and robust catalyst, large energy input required for desirable products, and low current densities (low yields)2.  All of these issues are being addressed by researchers in the field.

Copper metal has been found to produce the most desirable products, hydrocarbons, which can be used as fuel3. High surface area nanoporous copper catalysts were prepared using an in-house method. Galvanic displacement reactions using aqueous transition metal salt solutions were used to create nanoporous copper catalysts with a coating of a second transition metal.  Electrolysis was conducted using a custom built electrochemical cell and a Princeton Applied Research potentiostat.  CO2 reduction products were analyzed in-situ using a gas chromatograph with a mass spectrometer and thermal conductivity detectors. Liquid products were analyzed using nuclear magnetic resonance.

Results show unique selectivity for all variations of nanoporous bimetallic copper catalyst tested.  The pure nanporous Cu preferentially producing ethylene and ethane with very minimal methane.  On a typical polycrystalline copper catalyst, methane and ethylene are the majority hydrocarbon gases while ethane is rarely observed. A significant amount of formate was produced on nanoporous Cu, reaching 10% faradaic efficiency at potentials as low as -0.55 V vs RHE.  Selectivity of the catalysts can be significantly altered on bimetallic Cu surfaces.  Substantial increase in ethylene and ethane is observed and greater amounts of ethanol and propanol (~5% FE each) were produced.  Preliminary experiments using 13CO2 saturated solution have been performed and may provide insight into CO2 reduction pathways. Using mass spectroscopy and NMR, reaction products were monitored.  Product species containing the 13C isotope were observed for all CO2 reduction products and a comparison to 12CO2 experiments was made. Differences in the 13C/12C ratio may provide clues as to the carbon species responsible for the measured products. 

 

References

1.            Y. Hori, K. Kikuchi and S. Suzuki, Chemistry Letters, 1985, 1695-1698.

2.            Carbon Dioxide Utilization: Electrochemical Conversion of CO2 - Opportunities and Challenges, DNV, 2011.

3.            Y. Hori, K. Kikuchi, A. Murata and S. Suzuki, Chemistry Letters, 1986, 897-898.

4.            K. P. Kuhl, T. Hatsukade, E. R. Cave, D. N. Abram, J. Kibsgaard and T. F. Jaramillo, Journal of the American Chemical Society, 2014, 136, 14107-14113.
Artificial Photosynthesis: Photocatalytic Fixation of CO2
Authors: Zhou Yong , Wu Congping , Zou Zhigang
Published: February 2020

In recent years, the increase of carbon dioxide (CO2) in the atmosphere has become a global environmental issue because of the serious problems, such as the “greenhouse effect”. The idea of mimicking the overall natural photosynthetic cycle of chemical conversion of CO2 into useful fuels has been consistently gaining attention for more than thirty years. Such artificial photosynthesis allows direct conversion of CO2 and water on photocatalysts into valuable hydrocarbon using sunlight at room temperature and ambient pressure to serve to reduce atmospheric CO2 concentrations while providing on a renewable carbon fixation and energy storage.

In this presentation, we will report the utilization of solar energy to highly efficient conversion of CO2 into renewable hydrocarbon fuel over structured nanomaterials. The geometric shape and exposure of specific crystal planes of the nanostructures as well as combination of graphene as a good electron collector and transporter are a requisite for the high level of photocatalytic reduction of CO2.

[1] W. G. Tu, Y. Zhou, Z. G. Zou, Adv.
Mater. 2014, 26, 4607 (review article)

[2] Q. Liu, Y. Zhou, J. H. Kou, X. Y. Chen, Z. P. Tian, J. Gao, S. C. Yan, Z. G. Zou  J. Am. Chem. Soc.
2010,
132, 14385.
Renewable H2 Evolution Efficiency and Corrosion Tolerance of 5 Nickel Phosphide Crystalline Phases
Authors: Laursen Anders B. , Liu Bin , Izett Edward , Patraju Kelly , Whitaker Mariana J , Retuerto Maria , Sakar Tapati , Yao Nan , Ramanusjachary Kandalam , Greenblatt Martha , Dismukes G Charles
Published: February 2020

Renewable (electrical) energy from sources like photovoltaics and windmills, which are inherently intermittent, requires significant storage of the energy. Hydrogen(H2) from electrochemical water splitting offers a nearly unlimited renewable resource for energy storage and bulk chemical processing. Platinum(Pt), although scarce, remains the archetypical electrocatalyst for acidic H2 evolution. While several non-noble metal catalysts have been found, they all, except one, perform worse than Pt. Since 2013, many transition metal phosphides have been reported as possible replacements for Pt. Our group reported that one particular nickel phosphide phase, Ni5P4, is comparable to Pt in activity (geometrically) as well as corrosion resistant in both strong acid and alkali during electrocatalysis. Here, we will present comparative studies of the activity, efficiency and corrosion stability of five crystalline NixPy phases during electrocatalytic H2 evolution.  Supported by Rutgers, NATCO and NSF-CBET/DOE.

Figure 1
Ultra-Low NO2 Detection By Gamma WO3 Synthesized By Reactive Spray Deposition Technology
Authors: Jain Rishabh , Lei Yu , Maric Radenka
Published: February 2020

A porous tungsten oxide (WO3) film based NO2 sensor was developed by a one-step flame based process called Reactive Spray Deposition Technology (RSDT). The RSDT process allows the flexibility to create monoclinic gamma-WO3 with control of the particle size, porosity and thickness of the film. This nano-crystalline WO3 film was deposited directly on gold interdigitated electrodes. The sensor response was measured at the parts per million (ppm) level, (0.17-5 ppm in air at 100% relative humidity) at different operating temperatures (250-350°C) to determine the optimum working temperature. The sensitivity was  found to be maximum at 300 °C. The sensors showed a relatively fast response time (∼7s) and recovery time (∼5 min), respectively. The stability of the sensor was evaluated for 300 h in 0.5 ppm NO2 in air at 100% relative humidity (2000 response-recovery cycles). The sensor was stable up to 6 days (~150 h) of continuous operation and degraded between 150 to 300 h. In order to check the selectivity, the sensor was also tested for 10 ppm acetone, 100 ppm ethanol, 10-100 ppm H2, and 10 ppm isoprene. Interference was negligible with 10 ppm acetone, 100 ppm ethanol, 10 ppm H2 and humidity; however, it was significant with 10 ppm isoprene and 100 ppm H2. We have also compared the test data of this gamma WO3 based NO2 sensor prepared by RSDT with the results reported in the literature. The morphology and surface properties of the WO3 film were investigated with XRD, Raman spectroscopy, BET, SEM, TEM, and HRTEM. 

Here we will provide a brief description of the synthesis, fabrication and testing procedure of the NO2 sensor. The microstructure of the tungsten oxide films, and the effect of the film structure, grain size, and the sensor response to the ppm level concentration of NO2 will be described. The sensing mechanism with emphasis to adsorption and desorption will be explained in details.
Double-Layer Planar Coil Detector for Improved Detection of Salmonella on Food Contact Surfaces
Authors: Liu Yuzhe , Du Songtao , Horikawa Shin , Wikle Howard Clyde , Hu Jiajia , Wang Fengen , Chin Bryan A.
Published: February 2020

This paper presents an investigation into improved, direct Salmonella detection on food contact surfaces using a double-layer planar coil detector and wireless phage-based magnetoelastic (ME) biosensors. Comparing with the single-layer coil detectors used in our previous research, double-layer coils with appropriate designs allow for better magnetic excitation of the biosensor and sensitivity of detection. In this way, a longer stand-off distance (distance between the sensor and detector), which may be necessary for testing surfaces with large roughness and curvatures, can be achieved. In addition, smaller biosensors (e.g., sub-millimeter long) with higher mass sensitivity can also be measured with this sensitive double-layer coil detector. Standard microelectronic fabrication techniques (photolithography, electroplating, etching and sputtering) were used to fabricate double-layer coils with various design parameters, including the thickness of layers, width, height, and spacing of coil turns. Both theoretical calculations and experimental data showed that the above coil geometric parameters have large effects on the signal amplitude, stand-off distance and detection sensitivity. Finally, with the newly fabricated double-layer coil detector, detection of Salmonella on a food-grade, ultra-high-molecular-weight polyethylene (UHMW-PE) surface was demonstrated. Multiple biosensors were measured simultaneously with a longer detection distance (> 1 mm). This double-layer scanning coil detector therefore facilitates the detection of pathogens on food and food contact surfaces.
Development and Applications of Carbon-Based Solid-State Potentiometric Sensors
Authors: Ummadi J Ganesh , Joshi Vrushali S , Koley Dipankar
Published: February 2020

The solid-state ion-selective electrode (ISE) has been widely used in various applications due to its inherent properties of fast response time and ease of miniaturization. We have developed a new type of solid-state carbon-based ion-selective membrane to detect and quantify monovalent and divalent ions such as H+, Ca2+. Multiwalled Carbon nanotubes (MCNTs) have been used as carbon source in these carbon-based potentiometric sensors. The sensors were also miniaturized in the size of 25 to 40-micron diameter (μ-ISE). The Ca2+-μ-ISE showed fast response time (~1 sec or less), low limit of detection (~1 μM) and broad linear range (5 μM to 200 mM). In addition, the Ca2+-μ-ISE was proven to be insensitive towards redox molecules while demonstrating excellent selectivity towards major interfering ions (such as Na+, K+, and Mg2+, with logKCa
2+
,A = -5.5 to -6.0). The sensors were later used as a probe in Scanning Electrochemical Microscopy (SECM) to characterize Ca2+-releasing bioactive glass as well as monitoring real-time bacterial metabolic exchange in quorum sensing pathways. The recent development of this carbon-based miniaturized potentiometric sensors (Ca2+ and H+) and their application in live bacterial or biological systems would be presented at the meeting.
Sn-SnO2 Core-Shell Nanostructuresgrowth Mechanism and Their Thermal Properties
Authors: Wang Chiu-yen , Chen Sin-An , Chou Li-Jen , Chen Lih-Juann
Published: February 2020

Different configurationsof Sn-SnO2 core-shell nanostructures, including nanowire, nanocable and pea-pod,have been synthesizedviaone-step vapor-liquid-solid (VLS) growth mechanism.Systemic study for controlling varieties Sn-SnO2 core-shell nanostructures is carried through tuning temperature, size and amount of Au film / nanoparticles, ambient and growth time. In-situheating TEM was used to help us to investigate the growth mechanism, thermal stability andthermal expansion behaviors of the core-shell nanostructures. Meanwhile, the fact that Sn core has a high value of thermal expansion coefficient (TEC), and the TEC of the SnO2shell layer is relatively low can be revealed. Thermal expansion of Sn core property appears linear in the temperature region from 250 oC to 750 oC.In addition, a growth model of this kind of heterostructure nanostructures could be proposed and help to developed others nanomaterials.
Using Physics-Based Models and Redox Shuttles to Investigate the Effects of FEC on Electrode Passivation
Authors: Jaini Rajiv , Fuller Thomas F
Published: February 2020

Chemical additives, such as fluoroethylene carbonate (FEC), can be used to improve lithium-ion battery performance by facilitating the formation of a passivation layer on the negative electrode surface. We compare passivation layers formed by electrolytes with and without FEC, using the ferrocenium-ferrocene redox couple. To quantify experimental findings, we develop a mathematical planar-electrode impedance model to extract physical parameters related to the passivation layer.

Experimental cyclic voltammetry (CV) shows that the electronic passivity of the formed passivation layers is dependent upon the imposed electrochemical conditions. That is, potentiostatic holds cause surface passivation, leading to slower ferrocenium reduction kinetics. With increasing formation time, the high-frequency arc width of the impedance spectra increases for both electrolytes. However, the increase in high-frequency arc width is greater for electrolyte without FEC than that containing FEC. Formation potential influences the magnitude of electronic passivity of the solid electrolyte interphase (SEI), with more negative potentials increasing electronic passivity.

In Figure 1(a), the electrode surfaces have been passivated for 30 minutes under a 0.6 V potentiostatic hold. Two CVs are measured at ν = 10 mV s-1, comparing electrolytes with and without FEC. The addition of FEC to the primary electrolyte enhances ferrocenium reduction kinetics, when comparing peak heights and position. Figure 1(b) shows experimental and simulated impedance responses, obtained after 30 minutes of passivation around the redox shuttle equilibrium potential (3.24 V). Experimental and simulated impedance responses show good agreement over the frequency range shown, suggesting that reliable conclusions can be drawn about the SEI. Particularly, impedance response simulations suggest that interfacial kinetics and porosity of the outer layer of the SEI greatly influences the high-frequency arc width.

Figure 1
(Invited) Phase-Field Method of Li Dendrite Formation during Electrodeposition
Authors: Chen Lei , Liu Zhe , Qi Yue , Lu Peng , Chen Long-Qing
Published: February 2020

The recent attempts to model the Li-dendrite formation using the phase-field method will be briefly reviewed.  In particular, a nonlinear phase-field model, accounting for the Butler-Volmer electrochemical reaction kinetics, will be presented. The dendritic patterns are examined as a function of applied voltage and initial electrode surface morphology. A design map is proposed to tailor the electrode surface morphology and the applied voltage to avoid undesired dendritic patterns. The possibility of incorporating the effect of SEI on the Li-dendrite formation in a phase-field model will be discussed.
The State of Charge of Electrodes and Its Effects on Lithium-Iron-Phosphate Battery Simulation
Authors: Huang Hsuan-Han , Chung Wei-Lun , Liao Kuo-Chi , Lee Ching-Fei , Tien Jhen-Yang , Chen Hsun-Yi
Published: February 2020

A lithium-iron-phosphate (LFP) battery is one of the ideal energy storage devices owing to its outstanding characteristics such as high power output, no memory effect, and slow degradation. While electrochemical models have been widely used to simulate the LFP battery behaviors, we found the accuracy of simulated LFP battery characteristics, including the cell voltage, lithium concentration distribution, and cell capacity, are highly related to the initial concentrations, namely, the state of charge (SOC) of each individual electrodes.

The amount of active lithium in an LFP battery, which determines the cell capacity, is a result of the SOCs of the anode and the cathode at the beginning of charge or the end of discharge processes. The SOC also dictates the equilibrium potential of individual electrodes, which in turn contributes to the full cell potential. However, it is difficult to estimate the amount of lithium in each individual electrode after the activation cycles because a certain amount of lithium is consumed to form the solid electrolyte interface (SEI) layer. Incorporation of inaccurate SOCs in models could lead to erroneous cell potential and capacity estimation. In this study, the initial concentrations of the anode and the cathode are estimated from the experimentally measured equilibrium potentials. By evaluating the characteristic points of individual electrodes and the corresponding reference points of a full cell, on the basis of low-rate discharge potential curves, the SOC of each individual electrode can be accurately calculated.

In order to evaluate the discharge performance of the LFP battery and gain insight into the effects of electrode SOCs, an electrochemical model based on coupled mass balance, charge balance, and reaction kinetics constitution laws is developed. To determine the initial SOCs of individual electrodes of the LFP battery, equilibrium potentials are experimentally measured by low-rate discharge while the characteristic points are calculated by identifying critical points of the discharge curves. The LFP battery model with such formally determined SOCs is validated by comparing the simulated discharge curves with experimental measurements under various loading demands, up to 2C. The simulated voltage plateau is closely matching the corresponding experimental results for a range of SOCs as shown in Figure 1. Overestimated cell voltage near the earlier stage of discharge and underestimated cell capacity at all C rates are observed in our simulation results, which could be improved by precise measurements of equilibrium potentials of the electrodes and the full cell. Further understanding of the effects of lithium loss during activation process with experiments and model simulation can assist the LFP battery design and optimize fabrication.

Figure 1
Microstructure Morphology-Performance Relations in Porous Rechargeable Batteries
Authors: Robinson Lucas Darby , García R. Edwin
Published: February 2020

Understanding the effects of processing on the performance of Li-ion batteries is essential to the development of optimal battery technology. In this work, the non-idealities of microstructural properties of porous battery electrodes, such as particle morphology and compaction are numerically simulated to predict the power and energy response of porous battery systems. Here, by extending the well-known dualfoil software, a physical framework has been created to account for the effects of microstructural non-idealities on relevant battery design parameters, such as reactive area density and through-thickness tortuosity. The effect of particle alignment (texture) and particle morphology on the specific power and energy density are quantified and rationalized. Optimal aspect ratios for improved battery performance are proposed and discussed.
Deformation of Lithium Ion Battery Under Mechanical Loading
Authors: Kumar Abhishek , Allu Srikanth , Kalnaus Sergiy , Lebrun-Grandie Damien , Simunovic Srdjan , Turner John A , Wang Hsin
Published: February 2020

We report on an experimental and numerical study of deformation in cell/string/module of a lithium ion battery under mechanical loading. We performed compression tests on individual components of the battery cell, such as anode, cathode and separator, and used the results to calibrate the specific material models for these components. Indentations tests were performed on individual battery cells and on a stack of 3 cells. During the indentation test, load, voltage and temperature of the cell were measured. We also studied the evolution of deformation in various components of the cell in order to understand the mechanisms of failure in separator, which could result in an electrical short and thermal runaway of the battery.  

A finite element model (FEM) in which several layers are fully resolved and the remaining components are homogenized was developed for different cell combinations. In FEM maximum strain criterion in separator was used for element deletion and failure at short circuit.. We demonstrate the advantages of this approach by comparing the load-displacement curve and the nature of deformation obtained from simulations to those obtained from experiments.
Control and State of Charge Estimation of Lithium-Ion Battery Stacks
Authors: Pathak Manan , Sonawane Dayaram , Subramanian Venkat R.
Published: February 2020

There is no way to directly measure the state of charge (SOC) for a Lithium-ion battery. Various methods for estimating the state of charge have been proposed like extended Kalman filtering, coulomb counting and impedance spectroscopy but these are not entirely reliable [1, 2]. The models need to be recalibrated after a few cycles in order for accurately predicting the state of charge.  

The prediction of SOC of individual cells is even more important for a stack of cells in order to efficiently use the stack. Differences in the SOC of individual cells in a stack could lead to the cells being charged/discharged to different potentials, which could affect the safety of the stack or could damage the cells [2, 3, 4].  Cell balancing therefore is an important functionality of any Battery Management System (BMS) which necessitates the accurate estimation of SOC.

In this paper, we present the estimation of SOC of individual batteries in a stack using a physics based reformulated model [4], with the use of the voltage-time data while charging the cells. This kind of model adds more fidelity to the SOC estimation as the battery undergoes degradation after many cycles. Further, optimal charging profiles for the battery stacks could be suggested that would maximize the amount of charge stored while keeping the battery safe.  Reformulated models enable efficient simulation and control for online control applications.

 Acknowledgements

The work presented herein was funded in part by the Clean Energy Institute at the University of Washington, Seattle and the Advanced Research Projects Agency – Energy (ARPA-E), U.S. Department of Energy, under the Award Number DE-AR0000275.

References

V. Pop, H.J. Bergveld, J.H.G. Op het Veld, P.P.L. Regtien, D. Danilov, and P.H.L. Notten, J. Electrochem. Soc., 153 (11), A2013-A2022, 2006.

W.B. Gu and C.Y. Wang, J. Electrochem. Soc., 147(8), 2910–2922, 2000.

A. Szumanowski and Y. Chang, IEEE Trans. on Vehic. Tech., 57(3), 1425-1432, 2008.

P. W. C. Northrop, V. Ramadesigan, S. De, and V. R. Subramanian, J. Electrochem. Soc., 158(12), A1461-A1477, 2011.

F. Zhang, G. Liu and L. Fang, Advanced Intelligent Mechatronics, AIM, IEEE/ASME International Conference on , 1008-1013, 2008.

J. Newman, Electrochemical Systems, 2nd ed. Prentice Hall, 1991.   

V. Ramadesigan, K. Chen, N.A. Burns, V. Boovaragavan, R. D. Braatz, and V. R. Subramanian, J. Electrochem. Soc., 158(9), A1048-A1054,  2011.
Development of a Genosensor for Sickle Cell Anemia Trait Determination
Authors: Janegitz Bruno Campos , Brazaca Laís Canniatti , Bramorski Camila Barbosa , Cancino-Bernardi Juliana , Zucolotto Valtencir
Published: February 2020

Sickle cell anemia (SCA) is a common recessive genetic condition in which patients produce hemoglobin S (HbS), an abnormal form of the protein, instead of hemoglobin A, the regular form. SCA is caused by the substitution of a single nitrogenous base adenine for thymine (GAG-> GTG), encoding valine instead of glutamine.1 Deoxygenation of HbS leads to its polymerization, damaging the cell membrane and reducing the lifetime of erythrocytes dramatically – which, in turn, leads to anemia. In some regions of Africa, up to 40% of the population possess its genetic trait, being considered a public health serious problem2. As the disease is possibly deadly, presents very low cure chances and has limited treatment, carriers determination is a key feature to assist in reproducibility decisions. Currently, trait determination is mainly performed by liquid chromatography, electrophoresis and polymerase chain reaction (PCR)3,4. These techniques are not widely used due to its complexity, lack of portability, high price and specialized personal and equipment demand. In this study we have developed an electrochemical genosensor for simple, low cost and rapid SCA carriers determination. Single DNA strands corresponding to the sequence of a SCA carrier were immobilized in gold platforms using the self-assembled-monolayers technique. The determination of SCA trait is then performed by analyzing the film’s charge transfer resistance using Electrochemical Impedance Spectroscopy. The genosensor was able to distinguish between healthy and unhealthy subjects with great precision besides displaying a wide linear range (0.01 to 7.5 µmol/L, R2 = 0.927). Furthermore, the device presented a detection limit of 7.0 nmol/L. We expect that such devices increases the number of SCA carriers determination, promoting early diagnosis and genetical counseling.

References:

1              Barany, F. Genetic-Disease Detection and DNA Amplification Using Cloned Thermostable Ligase. Proceedings of the National Academy of Sciences of the United States of America
88, 189-193, doi:10.1073/pnas.88.1.189 (1991).

2              Diallo, D. & Tchernia, G. Sickle cell disease in Africa. Current Opinion in Hematology
9, 111-116, doi:10.1097/00062752-200203000-00005 (2002).

3              Ayatollahi, M. & Haghshenas, M. Application of the polymerase chain reaction to the diagnosis of sickle cell disease in Iran. Archive of Iranian Medicine
7, 84-88 (2004).

4              Bender, M. A. & Seibel, G. D. Sickle Cell Disease.  (University of Washington, 2003).
Tetracyanoborate Anion Based Phosphonium Ionic Liquids As Electrolytes for Pyrrole Electropolymerization
Authors: Nishihata Keiichi , Tsunashima Katsuhiko , Matsumiya Masahiko , Ono Yasushi
Published: February 2020

Room-temperature ionic liquids (RTILs) have been regarded as potential electrolytic media for electropolymerization processes.1 Many kinds of RTILs have been investigated for the electropolymerizations; however, RTILs based on tetracyanoborate (B(CN)4
-, TCB) anion have been rarely employed. On the other hand, we have designed quaternary phosphonium RTILs exhibiting high transport property and high stability.2 In this work, we report the physicochemical and electrochemical characterization of the phosphonium RTILs based on the TCB anion (Fig. 1) as electrolytes for electropolymerization of pyrrole (Py).

The preparation of the TCB-based phosphonium RTILs was performed by aqueous ion exchange reaction of the precursor quaternary phosphonium halides with sodium tetracyanoborate (Na-TCB). Residual metal and halide ions in the clude RTILs were removed by a silica gel column. The combination of the asymmetric phosphonium cations with TCB anion successfully gave liquids at ambient temperature. The TCB-based phosphonium RTILs showed thermal decomposition temperatures at more than approximately 400°C.

The electropolymerization of Py in the TCB-based phosphonium RTILs was carried out by cyclic voltammetry (CV) method. Fig. 2 showed the cyclic voltammograms for the electropolymerization of Py in P2225-TCB. It was found that an irreversible oxidation peak was observed and maintained when the cycle was repeated, giving the PPy films on the electrode surface. As shown in Fig. 3, the SEM images of the PPy films exhibited the relatively uniform surface when compared to the PPy films grown in the corresponding bis(fluorosulfonyl)amide-based phosphonium RTILs. The thermal stability of the PPy film grown in the TCB-based phosphonium RTILs will be also discussed.

References

1  K. Sekiguchi, et al, J. Electroanal. Chem.
,
557, 1 (2003).

2  K. Tsunashima, et al, Electrochem. Commun., 9, 2353 (2007).

Figure 1
The Performance of Hard Carbon in a Sodium Ion Battery and Influence of the Sodium Metal in Observed Properties
Authors: Ledwoch Daniela , Brett Daniel J.L , Kendrick Emma
Published: February 2020

Since the 1990’s and the commercialisation of the first lithium ion cell by Sony there has been a large focus on new materials for lithium ion batteries, and the work in the 1970’s and 80’s in room temperature sodium ion materials was lapsed. However, due to the high current cost of lithium ion batteries, alternative sodium ion technologies may offer a cost and safety advantage over the typical lithium ion cells.1,2 Sodium is a much more abundant metal when compared to lithium which should result in lower cost materials. Although the mass of sodium is higher than lithium, the observed specific capacity of a sodium ion battery compared to lithium is not hugely compromised; this is because the proportion of the sodium and lithium content is small enough that the difference is minimal.

Sharp Laboratories of Europe Ltd have been developing a new sodium ion cell chemistry based upon a layered oxide cathode3 and a hard carbon anode. The hard carbon anode is extremely sensitive to processing conditions and testing methods. In two electrode cells we have observed high hysteresis in the charge and discharge profiles and have experienced difficulties in reaching the low voltages required for complete sodiation of the hard carbon. In addition we have also observed high Coulombic inefficiencies during the testing in a sodium metal anode cell, and the instability of the sodium in certain solvents. By using 3-electrode cells we have been able to investigate the specific properties of the hard carbon in considerably more detail, and note that much of the hysteresis observed in two electrode measurements originates from the sodium metal anode. 3-electrode galvanic and potenstiostatic intermittent titration techniques have been used to investigate the properties of the hard carbon and sodium metal electrodes in more detail, and much of the hysteresis with regards to the performance of the carbon material in a 2-electrode cell can be shown to be related to the sodium metal deposition and stripping.

Figure 1 shows the galvanic intermittent titration technique (G.I.T.T.) for hard carbon vs sodium metal in a 3-electrode arrangement visualising the difference between cell potential (red) and potential of the working electrode vs sodium reference (hard carbon, blue).

V. Palomares, P. Serras, I. Villaluenga, K.B. Hueso, J. Carretero-Gonzalez and T. Rojo, Energy Environ. Sci. 2012, 5, 588,

J. Barker, M.Y. Saidi and J. Swoyer, Electrochem. Solid-State Chem. 2003, 6, A1,

E. Kendrick, R. Gruar et al, Tin containing compounds, WO2015177568A1, 2015-11-26

Figure 1
Optimization of Zinc Sensing Membranes to be Used in Ion-Selective Electrodes for the Determination of Zinc Ion Concentration for Agricultural Applications
Authors: Louis Wynstona , Hulce Courtney , Santra Swadeshmukul , Chumbimuni-Torres Karin Y.
Published: February 2020

Significant research has been focused toward the study of ion-selective electrodes (ISE) based on ionophore-doped polymer sensing membranes. One of the most substantial properties of these ISEs is their capability to measure target ion concentrations using a simple potentiometer.1 Little investigation has been focused on the development of ISEs targeting Zn2+ ions, which in excess can be harmful to both human and plant cells.2   Zinc concentrations have been measured at the cellular level by other methods such as anodic stripping voltammetry, atomic absorption spectrometry, and atomic emission spectrometry. However, these methods are invasive to the cellular environment, costly, and require significant sample manipulation.   As a result, environmental samples provide an opportunity for using ISEs in agricultural applications because ionic activity can be measured at the cellular level without disruption to the biological environment. Additionally, ISEs provide a cost effective, accurate, and fast method for  measurement of zinc ion concentration. It is known that the components of the membrane greatly influence the response of the sensor3. As a result, the membrane should be optimized towards obtaining an electrode with Nernstian response, good sensitivity and selectivity. For optimization of the composition of the membrane, the stoichiometric relationship between the ionophore and Zn2+ were analyzed using GaussView 5 computational software. The effect of the membrane components on the potential response and the selectivity coefficients of the zinc-selective electrodes were investigated. The equilibrium constant that describes the formation of a complex between an ion and a ligand is called the complex formation constant, which  was calculated using the sandwich membrane method4. Additionally, the equilibrium ion exchange process  was enhanced resulting in a shorter conditioning time. Preliminary results show response times of about 10s, a near-Nernstian response, and a good linear response ranging from concentrations of 10-6M  to 10-2M. Optimization of the zinc ISE will allow for the measurement of ion concentration without perturbing the biological environment for agricultural applications providing an unprecedented level of specificity and sensitivity.

1. P. Buhlmann, L. D. Chen, Supramolecular Chemistry: From Molecules to Nanomolecules, 2012, 5, 2539

2. A. K. Singh, S. Mehtab, U. P. Singh, V. Aggarwal, Anal. Bioanal. Chem., 2007, 388, 1867-1876

3. Bakker, E., P. Bühlmann, and E. Pretsch. Chemical Reviews, 1997. 97(8): p. 3083-3132

4. Bakker, E., Willer M, Lerchi M, Seiler K, Pretsch E.  Anal Chem. 1994. 66(4):516-21
A Pulse Voltage Application in Electrochemical Reduction of Solid CaWO4 Powder
Authors: Karakaya Ishak , Erdogan Metehan , Akpinar Bengisu
Published: February 2020

Among more than thirty known tungsten containing minerals, only scheelite (CaWO4) and wolframite ((Fe, Mn)WO4) are industrially important [1]. Scheelite is the most abundant mineral of tungsten, but wolframite is used more than scheelite due to easier dissolution in alkaline solutions used in present processing methods [2]. An alternative method based on electrochemical reduction of CaWO4by direct current applications in molten salt solutions was recently reported [3-5]. In this study, pulse voltage and constant voltage reduction mechanisms were compared and an optimization of reduction kinetics was achieved. Studies have shown that faster reduction rates could be achieved during pulse voltage applications compared to constant voltage applications, when average voltage value of pulse voltage application was the same as its constant counterpart. Furthermore, analysis of charge, energy and theoretical reduction graphs showed that reduction of calcium tungstate occurs at higher potential differences than 2.2 V, between calcium tungstate and graphite.

References:

[1] Brown, T. and Pitfield, P. (2013) ‘Tungsten’, in Gunn/Critical Metals Handbook. Wiley-Blackwell, pp. 385–413.

[2] Tang, D., Xiao, W., Yin, H., Tian, L., Wang, D. and and, L. T. (2012) ‘Dingding Tang’, Journal of The Electrochemical Society, 159(6), p. E139. doi: 10.1149/2.113206jes.

[3] Karakaya, I. and Erdogan, M. (2009)‘Production of Tungsten and Tungsten Alloys from Tungsten Bearing Compounds by Electrochemical Methods’, WIPO PCT application WO 2009/054819A1.

[4] Karakaya, I. and Erdogan, M. (2013) ‘Production of tungsten and tungsten alloys from tungsten bearing compounds by electrochemical methods’, CA 2703400Canadian Intellectual Property Office.

[5] Erdogan, M. and Karakaya, I. (2010) ‘Electrochemical Reduction of Tungsten Compounds to Produce Tungsten Powder’, Metallurgical and Materials Transactions B, 41(4), pp. 798–804. doi: 10.1007/s11663-010-9374-4.
Hybridization of Transition Metal Carbides (MXene) and Oxides for High Performance Li-Ion Storage
Authors: Torelli Michelle , Zhao Meng-Qiang
Published: February 2020

Two-dimensional (2D) materials, such as graphene, are attractive candidates for energy storage devices due to their large areas of electrochemically-active surfaces. Recently, MXenes, a new family of 2D carbides discovered at Drexel University in 2011, have shown promise for electrodes in Lithium-ion batteries and supercapacitors. The goal of this study was to determine if a combination of MXenes, which have high metallic conductivity but moderate capacity, and transition metal oxides (TMOs) with high lithium storage capacity but poor conductivity may result in improved performance.

Three different methods, including alternating filtration, spray coating, and in-situ growth, were employed to achieve the hybridization of Ti3C2 MXenes and TMOs. Flexible and free-standing Ti3C2/TMO papers were obtained. In these composites, the 1-nm thin flakes of Ti3C2-MXene provide superior conductivity, ensure mechanical integrity and flexibility, as well as some Li-ion storage capacity; the TMOs (e.g. Co3O4, NiCo2O4) nanosheets/nanorods serve as spacers between MXene flakes to improve the accessibility of electrolyte ions and provide additional capacity. The synergetic effect of the two materials leads to much improved performance compared to pure Ti3C2 or TMOs. The Ti3C2/TMO paper electrodes containing alternation layers of carbide and oxide achieved high reversible capacities of 1200-1400 mAh/g at 0.1C (10-hrs discharge), 4 times higher than commercial graphite anodes. These paper electrodes also exhibited excellent rate performance and superior cycling stability. A highly stable capacity around 500 mAh/g was retained for >1000 cycles at 1C rate (1-hr charge/discharge), with no obvious decay. This work provides a simple, scalable, and effective strategy for the fabrication of advanced electrode materials that can be used in wearable or structural electrochemical energy storage and conversion systems.
Enzyme Modified Microelectrodes Toward a Miniaturized Biofuel Cell Cathode
Authors: Einfalt Casey L. , Jones Benjamin J. , Fritsch Ingrid
Published: February 2020

The activity of immobilized laccase, from Trametes versicolor,on an electroploymerized poly(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methanol (PEDOT-OH) modified microelectrode for use as a bio-cathode in an enzymatic biofuel cell was measured electrochemically.  The activity of laccase, prior to immobilization, was determined by measuring the absorbance of an enzymatically oxidized substrate, syringaldazine, by using UV-Vis spectrophotometry.  The bio-cathode was constructed by modifying a gold microband electrode with PEDOT-OH and then immobilized laccase by cross-linking with glutaraldehyde, stabilizing with bovine serum albumin, and drop casting onto the electrode surface.  Cyclic voltammetry was used to characterize the electrode behavior both prior to and after modification with PEDOT-OH and laccase.  Chronoamperometry was conducted to measure the current response of the modified microelectrode as a function of increasing analyte concentration.  The data showed an increase in current density upon polymerization of the conductive polymer and an increase in current density with the immobilized laccase only when a mediator was present in the system.   

References

1.         Heller, A., Miniature biofuel cells. Physical Chemistry Chemical Physics, 2004. 6(2): p. 209.

2.         Meredith, M.T. and S.D. Minteer, Biofuel cells: enhanced enzymatic bioelectrocatalysis. Annu Rev Anal Chem (Palo Alto Calif), 2012. 5: p. 157-79.

3.         Gupta, G., V. Rajendran, and P. Atanassov, Laccase Biosensor on Monolayer-Modified Gold Electrode. Electroanalysis, 2003. 15(20): p. 1577-1583.

4.         Ribeiro, F.W.P., et al., Simple laccase-based biosensor for formetanate hydrochloride quantification in fruits. Bioelectrochemistry, 2014. 95: p. 7-14.

5.         Guerrieri, A., et al., Electrosynthesized non-conducting polymers as permselective membranes in amperometric enzyme electrodes: a glucose biosensor based on a co-crosslinked glucose oxidase/overoxidized polypyrrole bilayer. Biosensors and Bioelectronics, 1998. 13(1): p. 103-112.

6.         Zebda, A., et al., Mediatorless high-power glucose biofuel cells based on compressed carbon nanotube-enzyme electrodes. Nat Commun, 2011. 2: p. 370.
Producing Highly-Ordered Nanostructures through Pattern Transfer Onto Complex Substrates
Authors: Wong Justin C. , Ziegler Kirk J
Published: February 2020

Nanotechnology is quickly becoming part of our daily lives. Yet, while the creation and incorporation of nanotechnology is ever-increasing, there is still much to explore in the field. A notable area is in the formation and ordering of nanostructures. For many applications it is important to be able to consistently produce highly-dense nanostructures. One method we find useful for this purpose is the use of anodized aluminum oxide due to its high density and self-ordering. In this poster, we showcase a method for incorporating the properties of anodized aluminum oxide into complex, yet ordered nanostructures on multilayered substrates using a unique pattern transferring method. We present the process of this pattern transferring method to create complex nanostructures, with applications in nanowire arrays for precise sensors as well as alternative energy devices and carbon nanotube growth.
Aqueous Phase Synthesis Method of Ga Doped CuIn Nanoparticles and It's Application for CIGS Printable Solar Cell
Authors: Takahashi Hideyuki , Takagi Masaki , Yokoyama Shun , Tohji Kazuyuki
Published: February 2020

Because of the attractive performances of CIGS (Cu(In,Ga)Se2) type solar cell, various researchers tried to synthesis of it by using gas phase method or liquid phase reduction method in organic solvents. In the case of former, productivity is relatively low, since vaporizing temperature of three or more elements is extremely different, which read the large amount of waste of resources, nevertheless synthesized solar cell shows the high performances.

So, later methods were vigorously researched since it is ecological and also economical technique. For example, Ye et al. synthesized Cu-In alloy particles by using chemical reduction method in organic solvent and the Cu-In alloy precursor films were transformed to CuInSe2 films by selenization [1]. The resulting cells demonstrate a maximum energy conversion efficiency of 3.92 %. However, total cost of this method is not low since organic solvent should be used.

Therefore, we tried to synthesized uniform Cu-In (CI) alloy nanoparticles by using restrict controlling method of metallic complexes in an aqueous solution under room temperature [2]. In this method, reduction potential of the metal species can be controlled under the room temperature, consequently alloy nano materials with uniform and well crystallized structure can be successfully synthesized.

　　Therefore, in this study, to synthesize Cu-In-Ga (CIG) nanoparticles, aqueous phase Ga doping method to Cu-In (CI) alloy precursor materials were researched.

     Condition of Ga, Cu and In complex were calculated by using critical stability constants. Reduction potential of homogenized metal complex were analyzed by using cyclic voltammetry. Ga doped CI alloy nanoparticles were synthesized by using chemical reduction method under ambient conditions using metal chlorides as metal sources and sodium borohydride as a reducing agent.

By obeying to these calculation results and also electrochemical potential measurement, CI nanoparticles can be successfully synthesized in aqueous solution under room temperature. CuIn and also Cu2In ally nanoparticles can be synthesized.

XRD and SEM/EDX measurement demonstrated that Ga can be doped into CI nanoparticles, and doping ratio of Ga into CI nanoparticles were depended on the reduction rate and also reduction method. For example, maximum Ga concentration in CIG nanoparticles were reached c.a. 20% when the molar ratio of reducing agent against to metals reached to ten. Moreover, these results shows that reduction procedure was seriously affected to the doping ratio of Ga.

Another detailed results will be presented in our session.

This work has been supported by the Grant-in-Aid for Scientific Research (B) (No. 26281054).

 [1] Ye Seul Lim, et.,al, J. Phys. Chem. C, 2013, 117 (23), pp 11930–11940, [2] H. Takahashi et.,al, Applied Catalysis A: General 392 (2011) 80–85.
Role of Dummy Via Mask in Data Retention Capability of NAND Flash Memory
Authors: Lee Jung-Hwan , Jung Il Sub
Published: February 2020

The metallization scheme based on 3 metal layers was introduced in 3Xnm NAND Flash Single Level Cell (SLC) to reduce the chip size. However, the reliability issue related to hydrogen was caused by the additional PETEOS film deposition, which acts as the source of radical hydrogen. The passivated hydrogen at the Si/SiO2 interface can create the traps as a result of incomplete bonding through the electrical stresses. The outgoing levels of hydrogen before and after the added PETEOS deposition were measured using thermal desorption spectroscopy (TDS). By PETEOS alloy, although a number of characteristic improvements were obtained, the reliability capability was not reached to that of the previous 2 Metal structure. From the various annealing processes, it was found that hydrogen outgassing had been hindered by SiN layer on Cu metal layer. Therefore, via contact areas between Cu2 and Al were increased using dummy mask, thereby enhancing hydrogen outgassing. As the result, the similar reliability performance was obtained when it was compared to that of the metal 2 scheme. This paper presents the detailed analysis about the reliability degradation and introduces a solution in terms of hydrogen outgassing.