bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Multifunctional Surface-Enhanced Raman Spectroscopy (SERS) Probes for Targeted Detection of Cancer Cells
Authors: Li Ming
Published: February 2020

Cancer continues to raise global concerns with a significant mortality rate and an equally substantial socio-economic burden. As is well-known, cancer begins with out-of-control cell growth. To effectively screen and treat cancer, it is essential to identify and distinguish various subtypes of cancer cells as well as normal cells in solid tissues or body fluids, which will significantly improve personalized individual medical treatment. This talk will present our recent studies for identification and discrimination of subtypes of cancerous cells using surface-enhanced Raman spectroscopy (SERS).

The philosophy in our work is to actively target the overexpressed biomarkers on the surface of cancer cells with our functionalized SERS probes. The urea-based small-molecule inhibitor is grafted onto the SERS probe to endow with specificity for prostate-specific membrane antigen (PSMA) overexpressed on the surface of bone metastasis-derived, androgen independent isogenic PC3-PIP cells. Our finding shows high-resolution targeted SERS imaging of PC3-PIP cells in contrast to its phenotypically identical PC3-Flu cells with negatively-expressed PSMA. The significantly amplified SERS signal in the SERS probe endows the extraordinary sensitivity. The developed SERS routine is able to identify PC3-PIP cells in body fluids and solid tissues, providing an effective avenue for assessment of prostate cancer burden and image-guided surgery/treatment. Following this, a ratiometric SERS strategy is developed to discriminate breast cancer cells—MDA-MB-231 and MCF-7 cells. Two different SERS probes with distinct SERS signals are functionalized with two peptides that are able to specifically target the urokinase plasminogen activation receptor (uPAR) and epidermal growth factor receptor (EGFR), respectively. Our results show that we can distinguish MDA-MB-231 cells from MCF-7 cells by the SERS intensity ratio. The present finding offers a compelling approach to discriminate subtypes of cancerous cells to assess the progression and stage of cancer. More importantly, the present SERS technique has potential for the rapid identification and discrimination of subtypes of multiple cancerous cells owing to the powerful multiplexing capability in SERS.
Microfabrication and Characterization of Microwire Microbiosensors for Simultaneous Detection of Glutamate and GABA
Authors: Gong Chenggong , Hossain Imran , Doughty Phillip , Murray Teresa , Arumugam Prabhu U , Tan Chao
Published: February 2020

Glutamate (Glu) and γ-Aminobutyric acid (GABA) are the two most prominent neurotransmitters in mammalian brains. GABA, a major inhibitory neurotransmitter in the cerebral cortex, maintains the inhibitory tone of inhibition of neuronal excitation. Glu is a major excitatory neurotransmitter and plays an important role in neuronal excitation. High levels of Glu and GABA cause calcium overload and dysfunction of mitochondria and oxidative stress, which results in a variety of neuronal diseases such as Alzheimer's disease, stroke and epilepsy. The current detection methods (e.g. HPLC followed by electrochemical or spectroscopy detection) is bulky, time consuming and not suitable for real time continuous monitoring. In contrast, microbiosensors are easy to miniaturize and are well suited for in vivo studies. They selectively oxidize Glu and GABA into a secondary electroactive product (usually hydrogen peroxide, H2O2) in the presence of enzymes, which is then detected by amperometry. Unfortunately, this method is cumbersome because it uses a pre-reactor and relies on externally applied reagents. Here we report the design and implementation of a platinum (Pt) microwire-enabled GLU-GABA probe that consists of four enzyme-modified microwires. The microwires are uniquely modified with the enzymes and by simultaneously measuring and subtracting the H2O2 oxidation currents generated from these microbiosensors, GABA and Glu can be detected continuously in real-time without the addition of any externally applied reagents. We report the sensor metrics such as sensitivity, selectivity and long-term stability of the probe in in vitro and ex vivo (rat brain slice) microenvironments.
Microscale Surface Nanostructuration and Catalysis of Metallic Electrodes through Electrochemical Deposition and Dissolution in Ionic Liquids
Authors: Jiang Junhua , Mariani Robert
Published: February 2020

Incorporation of highly active nanostructures into metallic electrode surface layers is of particular interest for a wide range of potential applications, such as electrochemical sensing and energy storage-conversion systems, because the nanostructures not only can increase the active area accessible to reactant molecules but can also improve electron mobility in the solid ligaments. However, controlling the nano-architecture of electrode surface layers faces great challenges since metals at nanoscale favor low surface areas in order to minimize the surface energy. In the past two decades, several strategies such as template synthesis, surfactant mediated synthesis and dealloying, have been developed to design and fabricate nanostructured electrodes with highly ordered networks and high surface area. We have developed a green-chemistry method based on in-situ electrochemical deposition-dissolution (ECDD) of an active metal on a target metal substrate in ionic liquids to achieve the nanostructuration of metallic electrodes.1-4 As shown in Figure 1A, during electrochemical deposition, a highly reactive metal component such as Zn is introduced via electrodeposition to interact with a less active electrode substrate such as Au to form an alloy phase. During subsequent electrochemical dissolution, the reactive component is selectively removed from the alloy phase leading to the formation of nanostructured surface layers. The nanostructured layers can grow deeper by repeating the process. The most obvious advantage of the ECDD method over other arts is that no net chemicals are consumed and it is a green-chemistry process. This method has been employed to successfully create different nanostructures on single-element metal and alloy electrodes at tens-to-hundreds micrometer scales, which are shown in Figure 1B to E.

In this presentation, we will introduce the green-chemistry method based on the electrochemical alloying-dealloying in ionic liquids, the characterization and polarization behavior of resulting surface nanostructures, further catalysis of the nanostructures, and their applications to electrochemical sensing and energy storage conversion.

References

[1] J. Jiang, N. Holm, K. O'Brien, ECS Journal of Solid State Science and Technology
4 (2015) S3024-S3029.

[2] J. Jiang, L. Zhang, Electroanalysis
29 (2017) 2019-2026.

[3] J. Jiang, L. Zhang, ECS Journal of Solid State Science and Technology
4 (2015) N5084-N5088.

[4] J. Jiang, L. Zhang, X. Wang, ACS Appl. Mater. Interfaces
5 (2013) 12689–12694.

Figure 1
Engineered Electroactive Solutions for Electrochemical Detection of Volatile Organic Biomarkers Associated with Disease
Authors: Willis Christina Nicole , Misra Mano , Mohanty Swomitra K.
Published: February 2020

Rapid screening of tuberculosis (TB) by evaluation of associated volatile organic biomarkers (VOBs) in breath has been shown to be a promising technology that is significantly faster and more convenient than traditional sputum culture tests. Methyl nicotinate and methyl p-anisate have been isolated as specific biomarkers for the mycobacterium tuberculosis, as they are not found in high concentrations in ambient air or the breath of healthy patients, but should be readily present in all patients with active TB. A novel approach to detection of these biomarkers in liquid form (e.g. from breath condensate) using inexpensive screen-printed electrodes will be presented. Previous modelling studies [1] suggest that these biomarkers complex with certain transition metals (such as cobalt and copper) given a particular bias voltage and oxidation state of the metal. This interaction can be exploited by mixing the sample solution containing the biomarkers into an electroactive solution (EAS) containing the functional metal ion, and observing the change electrochemically. For example, the cyclic voltammogram of copper (II) changes significantly when as little as 1 mM methyl nicotinate (MN) is added to the solution. The variation of peak oxidation voltage with MN concentration can be seen in Figure 1 below. In order to further understand the reactions taking place and specifically identify the biomarkers, square wave voltammetry (SWV) is employed to show which oxidation states of the functionalized metal are complexing with the biomarker of interest. Figure 2 shows the SWV of a copper EAS with and without 1 mM MN. The SWV shows a peak for each redox transition of copper, and how the area of each is affected by the addition of the biomarker. In this way, a “fingerprint” method can be used to identify biomarkers once their known interaction is established.

[1] Ray R, Sarma B, Mohanty S, Prisbrey K, Misra M. Assessment of metals in detection of TB biomarkers: Novel computational approach. Journal of Materials Chemistry and Physics. 161 (2015) 1-8

Figure 1
(Invited) Multi-Material Additive Manufacturing (3D/4D printing)
Authors: Khosla Ajit , Basher Samiul , Thundat Thomas , Bhansali Shekhar , Nagahara Larry A. , Kawakami Masaru , Furukawa Hidemitsu
Published: February 2020

Like any other manufacturing technology, Additive Manufacturing (AM) suffers from certain limitations. Grand challenges that hinder the use of AM in the field of sensors, actuators and energy are:

lack of materials available for AM

multi-material AM

feature size and accuracy

In order to overcome the grand challenges that hinder the use of AM in the field of sensors, actuators and energy, we have developed a universal multi-material 3D/4D printer which is capable of printing metals, thermoplastics, gels, pastes, elastomers and nanocomposites [1, 2]. The developed 3D printer is unique in that sense that it employs a screw-based extrusion system. The materials to be 3D printed (also known as feedstock) are fed into the hopper, single screw extrusion system mixes and melts the material, remove any air bubbles, extrudes the material through a nozzle of 100 micron, ensuring 3D/4D printing without any defect [3]. By using the developed universal multi- material 3D printer we have been able to 3D/4D print Steel, Aluminium, Silver, Nickle, Cobalt, Copper, Carbon fibre based nanocomposites, Ionic gels, Titanium dioxide, various thermoplastics, Shape memory materials, Wood and Epoxies as shown in figure 1. Such type of single screw base extruder 3D/4D printer will be a new addition to the additive manufacturing process.

References:

Shiblee, Md Nahin Islam, Kumkum Ahmed, Ajit Khosla, Masaru Kawakami, and Hidemitsu Furukawa. "3D printing of shape memory hydrogels with tunable mechanical properties." Soft matter (2018). DOI:10.1039/C8SM01156G

Khosla, Ajit, et al. "Carbon fiber doped thermosetting elastomer for flexible sensors: physical properties and microfabrication." Scientific reports 8.1 (2018): 12313. https://doi.org/10.1038/s41598-018-30846-3

Shah, Shreyas, et al. "3D printing of electrically conductive hybrid organic–inorganic composite materials." Microsystem Technologies 24.10 (2018): 4341-4345. https://doi.org/10.1007/s00542-018-3781-x

Figure 1
(Invited) Microfabrication and Electrochemical Activation of Amorphous Carbon Nitride a-CNx Working Electrode Integrated in Microfluidic Chip
Authors: Horny Marie-Charlotte , Billon Florence , Siaugue Jean-Michel , Dupuis Vincent , Lazerges Mathieu , Deslouis Claude , Pailleret Alain , Gamby Jean
Published: February 2020

a-CNx ﬁlms are well-known polarizable interface materials with a large potential window (3 V-4 V [1]) interesting electrochemical reactivity [2] and tunable chemical surfacic composition [3]. Indeed, the surface structure, surface properties, number of grafting sites available are tunable according to the atomic percentage of nitrogen in the a-CNx [4]. High surface reactivity are highly dependent on the surface state and can be affected by synthesis (by varying the Csp3/sp2 ratio), and by pre-treatment (electrochemical or plasma). In this work, we elaborated a microﬂuidic chip integrating a-CNx as working microelectrodes. In brief, a titanium/ platinum (50/500 Å) underlayer was first deposited on the glass wafer and patterned as working microelectrodes for the future thin film a-CNx adhesion and conductivity. On the top of the working electrode, a 220 nm a-CNx (x=0.12), layer was deposited with DC magnetron sputtering (time =20 min, power=200 W) with a graphite target under a ﬂow of nitrogen (PN2/Ptot =3%, Ptot =0.4 Pa). Then, a classical PDMS fluidic circuit was microfabricated and pre-treated with nitrogen plasma to favor its adhesion onto the glass slide containing the Ti/Pt/ a-CNx microelectrodes. The a-CNx microelectrodes were also electrochemically pre-treated in galvanostatic mode using 0.1 M KOH solution (anodic pre-treatment). The hydrodynamic properties of the fluidic channel a-CNx microelectrodes (as-grown and pre-treated) were screened with the [Fe(III)(CN)6]3−/[Fe(II)(CN)6]4− redox couple by cyclic voltammetry and impedance spectroscopy to provide a basis for further investigations such as the inﬂuence of a-CNx electrode pre-treatment on the DNA probe density issues in order to enhance the hybridization reaction efficiency with its specific DNA target.

[1]. A. Lagrini, C. Deslouis, H. Cachet, M. Benlahsen, and S. Charvet. Elaboration and electrochemical characterization of nitrogenated amorphou scarbon ﬁlms, Electrochem. commun., 6(3) (2004) 245–248.

[2]. G Adamopoulos, C Godet, C Deslouis, H Cachet, A Lagrini, and B Saidani. The electrochemical reactivity of amorphous hydrogenated carbon nitrides for varying nitrogen contents: the role of the substrate. Diam. Relat. Mater.,12 (2003) 613– 617.

[3]. R A Medeiros, A Benchick, R C Rocha-Filho, O Fatibello-Filho, B Saidani, C Debiemme-Chouvy, and C Deslouis. Simultaneous detection of ascorbic acid and dopamine with electrochemically pretreated carbon nitride electrodes: Comparison with boron-doped diamond electrodes. Electrochem. commun., 24 (2012) 61–64.

[4]. M Faure, F Billon, A M Haghiri-Gosnet, B Tribollet, C Deslouis, A Pailleret, and J. Gamby. Influence of the atomic nitrogen content in amorphous carbon nitride thin films on the modulation of their polarizable interfaces properties. Electrochim. Acta, 280 (2018) 238-247.
Fabrication of Flexible Energy Storage Device Using MnO2@Graphene Composite Synthesised By Electrochemical Exfoliation Method
Authors: Das Himadri Tanaya
Published: February 2020

Conventional energy storage devices have relied upon the ability of the electrochemically active materials to store the charge in the wide potential region with high Coulombic efficiency. Transition metal oxides are considered as ideal electrode materials in various energy storage devices, owing to their unique features, namely, high theoretical specific capacity; pseudocapacitive nature and ability to deliver large energy and power density. However, it suffers from many drawbacks, such as, low electronic conductivity and capacity fading with number of cycles. To address these shortfalls metal oxides are, usually, embedded within a conductive carbon-based matrix (for example graphene). The use of graphene would afford easy pathway for electron movement and increases the surface area for higher interaction of active electrode materials with electrolyte. Subsequently, graphene based transition metal oxides composites have attracted active research pursuits in synthesizing the low cost effective electrode materials for energy storage devices.

In this work, we report a facile and economic approach to produce manganese oxide nanorods amalgamated on the graphene sheets (MnO2@G) powders with an aim to achieve improved electrochemical activity. This electrochemical exfoliation strategy demonstrates a synthesis scheme from the graphite sheets at a constant voltage of 10 V in the MnSO4 bath solution, the outcome of which are the black shinny flaky powders. The crystallinity MnO2@G powders' was confirmed by XRD analysis. The TEM reveals the incorporation of MnO2 nanorods on the exfoliated few layers of graphene nanosheets. The physiochemical and electrochemical properties were tuned by varying concentrations of MnSO4 solutions. Interestingly, it was found that the yield of graphene as well as the performance of MnO2@G governed by the concentrations of salt solution. The degree of graphitisation in the as prepared materials was investigated by depth analysis in the Raman spectroscopy. Further, the electrochemical performances of MnO2@G were examined by cyclic voltammetric, charge-discharge and electrochemical impedance spectroscopy studies in a three electrode set-up. It was discovered that the MnO2@G composite prepared using 0.1 M MnSO4 solution has a delivered better electrochemical performance. To realise the practical applicability of the MnO2@G composite, flexible light-weight solid-state prototype asymmetric supercapacitor was fabricated using MnO2@G as positive and graphene as negative electrode. The fabricated devices exhibited ample storage capacity along with high energy density and powder density which were capable of powering consumer electronics applications. Thus, in the present work we have developed a cheap and effective electrochemical preparation of exfoliated MnO2@G composites in high yield. This scheme could serve as precedent to the development of potential electrode materials for energy storage devices.
Effect of the Cooling Process on the Structure and Charge/Discharge Cycling Performance of Li2MnO3 -LiNi0.5Mn0.5O2 -LiNi1/3Co1/3Mn1/3O2 Li-Rich Solid-Solution Layered Oxide Cathode Materials for Li-Ion Battery
Authors: Nomura Fumihiro , Gunji Takao , Ohsaka Takeo , Matsumoto Futoshi
Published: February 2020

The effect of the cooling process on charging/discharging capacities of Li2MnO3- LiNi1/2Mn1/2O2-LiNi1/3Mn1/3Co1/3O2 Li-rich solid-solution layered oxide (LLO) cathode materials for lithium ion battery was examined by applying two types of the cooling processes of quenching the calcinated LLO samples with nitrogen liquid and slow cooling of the LLO samples in the furnace at the controlled decreasing rate of the temperature to thirteen LLO samples having different compositions. The results of the comparison between discharging capacities observed with the LLO samples prepared with two types of the cooling processes indicated that the cooling process for the LLO samples to exhibit high discharge capacity was not limited to either one. Which process was effective for the LLO samples to exhibit high discharge capacity depended on the composition of the LLO samples. In the composition of the Li[Li0.20Mn0.58Ni0.18Co0.04]O2 sample (Li2MnO3 (60%) -LiNi0.5Mn0.5O2 (30%) - LiNi1/3Co1/3Mn1/3O2 (10%)) which exhibited the best cathode performance among the LLOs examined, the effect of quenching was maximum and as the composition of the LLOs went away from the composition of the Li[Li0.20Mn0.58Ni0.18Co0.04]O2 sample, the effect of quenching became smaller and slow cooling process was superior to the quenching process. The structural difference of the LLO samples prepared with two types of the cooling process was made connection with the cathode performance observed.

Figure 1
Potential Dependences of Discharge Characteristics of Li-O2 Batteries with Various Electrolytes
Authors: Nishioka Kiho , Morimoto Kota , Kusumoto Takayoshi , Seki Juntaro , Hase Yoko , Nakanishi Shuji
Published: February 2020

Practical application of non-aqueous Li-O2 batteries is strongly expected, as its theoretical energy density is much larger than Li ion batteries. However, due to non-conductive Li2O2 formed on the cathode during the discharge, the discharge capacity is limited to be much smaller than the theoretical value. Two different pathways, the surface and solution pathway, have been proposed for the discharge process forming Li2O2, the latter being considered preferred for the sustained discharge. Recent works revealed that the formation pathway of Li2O2 is determined by the adsorption/desorption equilibrium of LiO2, a reaction intermediate of the discharge reaction. Considering that the operating potential of the cathode is one of the factors which determines the adsorption/desorption equilibrium of LiO2, it is effective to conduct the discharge tests under potential-controlled modes for deeper understanding of the electrochemistry of the discharge reaction. In the present work, we examined the discharge profiles of non-aqueous Li-O2 batteries under potential-controlled conditions. We put a particular interest on revealing the generality and specificity of the potential dependences of the discharge characteristics among Li-O2 batteries carrying different solvents, including dimethyl sulfoxide (DMSO), acetonitrile (MeCN), and tetraglyme (G4). For all the systems investigated qualitatively similar potential dependences were observed. Namely, the higher (or the lower) the potential was, the smaller (or larger) the current value was and the larger (or smaller) the discharge capacity was, suggesting that the solution and surface pathway preferentially proceeds in higher and lower potentials, respectively, irrespective of the solvents. On the other hand, it was also found that the sharpness of the potential dependence strongly depends on the kind of solvents used. For example, the potential dependence of the discharge capacity in MeCN was much sharper than that in DMSO. These results indicate that it is important to tune the working potential of the cathode so that the discharge capacity can be larger, especially in a solvent which has the strong potential dependency.

Figure 1
Promoting the Cyclic Performance and Boosting Li+transport of LiV3O8 Via Ca Doping
Authors: Xu Yinsheng
Published: February 2020

As one of the most promising cathodes for rechargeable Lithium ion battery, LiV3O8 commonly suffers from inevitably complicated phase transitions and sluggish kinetics. Here, we develop a Ca doping technique to

tackle this long-standing issue of instability and improve the rate performance of LiV3O8. The dopants are found to reside in the Li site ofLiV3O8, where works as a pillar to increase the a axis distance facilitating Li diffusion, stabilizing the structure and suppressing the phase transition during cycling. This doped LiV3O8 displays an exceptionally high capacity of 280 mAh g-1, cyclability with 87% capacity retention over 100 cycles and significantly enhanced rate capability.
Corrosion Behavior of Fe-Cr-Al Alloy for Anode Current Collector in Oxygen Atmosphere
Authors: Woo Hwa-Young , Kwon Suk-Cheol , Lee Jong-Hyeon
Published: February 2020

Solid Oxide membranes (SOMs) have been applied to metal production through oxide reduction in order to accomplish low-cost production of primary products through simple pre-processing, low capital costs, small manufacturing plants, and low energy costs. Especially, the SOM process is eco-friendly, which makes it even more attractive. The SOM process is a direct electrolytic reduction process using a solid-oxide oxygen ion conducting membrane with high-temperature molten salts as a reaction medium. The transported oxygen ions from the cathode during the direct electroreduction process create a chemically harsh environment that can be corrosive for the alloy. Therefore, there is a need for the high-temperature corrosion behavior of alloy in high-temperature oxygen atmosphere. In this study, the hot corrosion behavior of FeCrAl alloy was investigated at 1150 ℃ in oxygen atmosphere with alumina shielding and without alumina shielding. The surface and cross-sectional morphologies and the characteristics of alloy were analyzed by SEM, EDS. As a result, FeCrAl alloy with alumina shielding was less oxidation than that without alumina shielding.
Probing the Effect of Point of Use Filtration on Cu CMP Slurry Health
Authors: Salinas Maria G , Zubi Tala B , Keleher Jason J.
Published: February 2020

Chemical mechanical planarization (CMP) is a process that balances chemical surface modification and mechanical removal utilizing a nanoparticle dispersion (slurry) to limit defects and irregularities on the wafer surface. Implementing point of use (POU) filtration prior to the CMP process is crucial in capturing rogue particle aggregates that are known to induce defects such as scratching and pitting. As technology continues to advance CMP slurries are increasing in complexity, making it necessary to unravel the dynamic synergy between the formulated slurry and filtration media. More specifically, this work set out to investigate the non-covalent interactions such as hydrogen bonding, pi interactions, or dispersion forces that occur at the interface of a fundamental Cu CMP slurry and a polyamide and polypropylene based media. The slurry utilized in this study contained SiO2 abrasive particles due to its selectivity for Cu, glycine as a complexing agent, benzotriazole (BTA) as a passivating agent, H2O2 as an oxidizing agent, and pH adjusters. It has been known that Cu-glycine complexes increase the hydroxyl radical concentration, which in turn enhances the MRR. Initial results revealed that there was a subtle difference in the MRR post-filtration independent of the media used, meaning that both filters were capable of interacting with the chemistry in the slurry during the filtration process. In order to determine what chemistry was being removed through adsorption the following techniques were employed as a function of the filtration process, dynamic light scattering (DLS), zeta potential, electrochemical quartz crystal nanobalance (EQCN), UV-Vis spectroscopy, potentiodynamic scan analysis, and measuring Cu removal rate. Ultimately, results show that both polymeric media, despite the difference in their characteristics (backbone structure, hydrophilicity, and pore size) were not only effective in removing large particle aggregates but were able to alter the slurry integrity by removing key complexing chemistry, which significantly impacts the Cu film formation and removal processes.
An Investigation of the Role of Rapid Chlorine Hydrolysis on the Performance of Electrochemically-Mediated Desalination
Authors: Davies Collin David , Johnson Sarah , Crooks Richard M
Published: February 2020

A recent United Nations report estimates that more than two billion people presently lack access to clean drinking water and more than four billion people lack access to proper sanitation. Furthermore, steadily rising populations, a changing climate, and growth in the agriculture, energy, and manufacturing sectors jeopardize future water security in many parts of the world. Accordingly, energy-efficient separations of salts and trace contaminates from water represent one of the most significant (and difficult) challenges facing humankind. To address this problem, we have previously reported the development of a promising approach to the separation of salts from seawater which we refer to as electrochemically-mediated desalination (EMD). EMD is an electrokinetic technique which utilizes the electric field gradient formed local to an anode during chloride oxidation to separate charged species from pure water. Despite experimental and computational study of EMD, a deep understanding of phenomena fundamental to the technique has yet to be attained. To this end, we performed time-resolved high resolution electric field gradient measurements and direct conductivity measurements during electrochemical chloride oxidation within a simple system composed of microelectrodes embedded in a straight microchannel. We were surprised by the findings of these measurements. Specifically, a large electric field gradient was measured upstream of the anode during chloride oxidation, however, a local increase in solution conductivity was measured at the same axial position along the channel length during chloride oxidation. To address these seemingly contradictory findings, the experimental system was simulated by finite element modeling. Simulation results showed that electrochemically generated chlorine undergoes rapid hydrolysis and produces substantial quantities of HOCl, H+, and Cl- near the anode. This finding corroborates the experimentally observed increase in solution conductivity near the anode during chloride oxidation. Consequently, we hypothesize that the observed electric field gradient is not indicative of local solution conductivity, but rather is related to a surface interaction between a product of chloride oxidation and the Pt microband electrode used to probe the electric field gradient. Ongoing research seeks to confirm this claim. Ultimately, we conclude that complex aqueous chlorine chemistry significantly limits the utility of chlorine generation for the formation of a local electric field gradient and seawater desalination.
Scale Formation on Na4Mn9O18 Insertion Electrodes in Electrochemical Deionization
Authors: Zhang Yueheng , Shanbhag Sneha , Mauter Meagan , Whitacre Jay
Published: February 2020

Several sodium insertion materials have been used as cathode materials in electrochemical deionization. [1][2][3][4]In this work, we evaluate the performance of sodium manganese oxide (Na4Mn9O18/ NMO), a layered insertion compound in separating sodium ions from a mixed cation (Na+/Ca2+) system (figure1). We observe that the specific capacity of a composite Na4Mn9O18/C electrode in 1M NaCl solution is 54 mAh/g, and is reduced to 23 mAh/g in 0.2 M CaCl2+ 1 M NaCl. We also observe that the capacity is not fully recovered when the electrode cycled in mixed ion solution is electrochemically cycled again in 1M NaCl. The X-ray diffractograms of the electrodes cycled in the mixed ion solutions reveals that in addition to the Na4Mn9O18 phase there is a second phase comprising primarily of calcite CaCO3. The presence of calcite on the NMO electrode is confirmed using SEM/EDX and XPS. It is expected that calcite is formed during the oxidation of carbon particles in close contact with NMO particles in the composite electrodes, and the capacity loss occurs due to the calcite layers that hinder ion transport to the NMO particles. [5]

Reference

[1] M.E. Suss, V. Presser, Water Desalination with Energy Storage Electrode Materials, Joule. 2 (2018) 25–35. doi:10.1016/j.joule.2017.12.010.

[2] S. Shanbhag, Y. Bootwala, J.F. Whitacre, M.S. Mauter, Ion Transport and Competition Effects on NaTi2(PO4)3and Na4Mn9O18Selective Insertion Electrode Performance, Langmuir. 33 (2017) 12580–12591. doi:10.1021/acs.langmuir.7b02861.

[3] J.F. Whitacre, A. Tevar, S. Sharma, Na4Mn9O18as a positive electrode material for an aqueous electrolyte sodium-ion energy storage device, Electrochem. Commun. 12 (2010) 463–466. doi:10.1016/j.elecom.2010.01.020.

[4] F. Sauvage, L. Laffont, J.M. Tarascon, E. Baudrin, Study of the insertion/deinsertion mechanism of sodium into Na 0.44MnO2, Inorg. Chem. 46 (2007) 3289–3294. doi:10.1021/ic0700250.

[5] C. Zhang, D. He, J. Ma, W. Tang, T.D. Waite, Faradaic reactions in capacitive deionization (CDI) - problems and possibilities: A review, Water Res. 128 (2018) 314–330. doi:10.1016/j.watres.2017.10.024.

Figure 1
Synthesis of Cobalt Selenide Thin Films and Their Electrocatalytic Properties in Water Splitting Process
Authors: Kwiecińska Anna Maria , Kutyla Dawid , Kolczyk Karolina , Skibinska Katarzyna , Zabinski Piotr , Kowalik Remigiusz
Published: February 2020

Chalcogens of transition metals thin films may be a cheapest and well-efficient replacement for the noble metals in various chemical and electrochemical processes. This paper presents the results work on the electrochemical deposition of Co-Se coatings from aqueous acidic solutions. Co-Se coatings were obtained by the potentiostatic method on a copper substrate. The elemental composition was determined with the XRF method. Crystallographic structure was investigated according to XRD measurements. The influence of applied potential and concentration of electroactive species on the composition and the quality of the obtained coatings was determined. Additionally, the CV's and chronopotentiometric measurements were used to examine the catalytic activity of different Co-Se alloys in water splitting process.

This work was supported by the Polish National Center of Science under grant 2016/21/B/ST8/00431
Non-Volatile, Multi-Level Optical Information Storage of Block Copolymer Structural Color
Authors: Eoh Hongkyu , Kang Han Sol , Park Tae Hyun , Kim Kang Lib , Lee Hyeokjung , Park Cheolmin
Published: February 2020

Structural colors (SCs) of photonic crystals (PCs) have attracted much attention due to their broad applications in the field of displays, sensors, and media boards. Compared with different PCs, the block copolymer (BCP) based PCs has an easy processing route due to the self-assembled microstructure of BCP. Here, we demonstrate a non-volatile, multi-level optical information storage of BCP SC. Our method is based on the controlled cross-linking of the BCP PC's microdomains resulting from the photo-thermal conversion. The process of photo-thermal writing is accomplished by time, power, and position controlled near infrared (NIR) laser exposure on a poly (styrene-block-quaternized 2-vinyl pyridine) (PS-b-QP2VP) PC on a photo-thermal conversion layer consists of poly (3,4-ethylenedioxythiophene) doped with tosylate. The localized heat arising from the NIR-to-thermal conversion of the photo-thermal conversion layer is exerted on the BCP PC with alternating in-plane PS and QP2VP lamellae stacks. Thermal cross-linking consequentially occurs between quaternized pyridines due to heat transfer, which results in a programmed SC upon reading process with a swelling agent, ethanol. The degree of cross-linking of QP2VP domains is dependent upon laser-power and exposure time, allowing for multi-colored recording of SC per single spot, giving rise to a novel multi-level optical recording media based on BCP SC.
Growth of High-Quality GaN Films on Multi-AlN/Sapphire Templates By MOCVD
Authors: Bun Kheam
Published: February 2020

GaN is an attractive material for the applications in visible and ultraviolet optoelectronics, high power, high temperature and high frequency devices. Sapphire substrates have been widely used for the growth of GaN films. However, it is difficult to grow high quality GaN films because of lattice constant and thermal expansion coefficient between GaN and sapphire substrate. In this paper, we report on the high quality GaN films have been successfully grown on multi-AlN/sapphire templates by metal organic chemical vapor deposition system. The Hall mobility and the carrier concentration of 801 cm2/Vs and 7.9x1016 cm-3 at 300K, respectively, along with low dislocation density of 4.5x107 cm-2 have been achieved. The X-ray rocking curve full-width at half-maximum were 51 and 211 arcsec for (0004) and (20-24) reflection planes also obtained, respectively. Besides that the atomic force microscopy images showed smooth surface morphology and a higher intensity near the band edge was also observed by photoluminescence measurement result.
Annealing Studies of RF Sputtered CuGaO2 Thin Films
Authors: Saikumar Ashwin Kumar , Sundaram Kalpathy B.
Published: February 2020

Research conducted in the field of transparent conducting oxide films have been focused majorly on the N type transparent conducting oxide films like ZnO, ITO, etc. P-type transparent conducting oxide films have been studied comparatively lesser. More and more research are being done on P-type transparent conducting oxide films to progress in the field of transparent p-n junction devices.

For this work, CuGaO2 (50:50 of Cu2O: Ga2O3) thin films was RF sputter deposited onto glass slides and quartz slides in the presence of oxygen. Deposition and optical transmission studies were performed on these annealed thin films. Subsequently the sputtered samples were systematically annealed at different temperature in different ambient conditions. Optical transmission studies were performed on these annealed CuGaO2 thin films.
Optical Studies of RF Sputtered CuInO2 Thin Films
Authors: Skaria Giji , Saikumar Ashwin Kumar , Nehate Shraddha Dhanraj , Sundaram Kalpathy B.
Published: February 2020

N type transparent conducting oxide semiconductors have been researched extensively in the past. P-type transparent semiconductors have been comparatively researched lesser. In order to advance in the field of transparent p-n junction devices, more and more researches are being done on p-type transparent semiconductors. CuInO2 is one of the p-type transparent semiconductor that has the prospects of being used extensively in transparent p-n junction devices.

CuInO2 (50:50 of Cu2O: In2O3) thin films were RF sputter deposited onto glass slides. Optical transmission studies were performed on these thin films to extract the band gap. The deposition studies were also performed. The sputtered films were subsequently post annealed in different temperatures and different ambient conditions and their respective optical transmissions were recorded.
Study of Transport Behavior in an Anion Exchange Membrane Fuel Cell
Authors: Sarker Mrittunjoy , Mojica Felipe , Chuang Po-Ya Abel
Published: February 2020

Currently, anion exchange membrane fuel cells (AEMFC) are gaining strong interests from researchers because it provides great potential for applying non-precious metal in comparison to the proton exchange membrane fuel cells (PEMFC). The alkaline oxygen reduction reaction (ORR) has lower cathodic activation overpotential than ORR in a PEMFC. In addition, low-cost stainless steel can be used as flowfield material, instead of more expensive metals or high-purity graphite because corrosion of the bipolar plate is less of an issue in the alkaline environment. However, there are still many technical challenges existed in AEMFC research. One key challenge is related to the transport of reactants and product in and out of the catalyst layer. Different from a PEMFC, water is actively participating in anodic hydrogen oxidation reaction (HOR) as a product and cathodic ORR as a reactant. Therefore, anode flooding and cathode drying are concerns for operating an AEMFC under high current density conditions. This complicates the study of transport behavior in an AEMFC because transport limitation may occur due to one or a combination of hydrogen, oxygen, hydroxide, and water. Additionally, hydroxide transport in the membrane strongly relies on proper hydration, which may induce severe polarization losses due to membrane and ionomer conductivity caused by drying. Therefore, adequate water balance combined with effective reactant/product transportation are essential in achieving good performance for an AEMFC. In this work, we focus on studying the effect of operating conditions on fuel cell performance experimentally. Key parameters include relative humidity, temperature, pressure, and inlet gas concentration. An in-situ diagnostic tool, limiting current method1, is employed to analyze transport behaviors in an AEMFC. Differential conditions are achieved by using a straight parallel flowfield with 2 cm2 active area as shown in Figure 1. Our aim is to identify sources of transport limitations and quantify their effect under various operating conditions. Detail experimental and analytical results will be shared at the conference.

References:

Baker, D. R., Caulk, D. A., Neyerlin, K. C. & Murphy, M. W. Measurement of Oxygen Transport Resistance in PEM Fuel Cells by Limiting Current Methods. J. Electrochem. Soc.
156, B991 (2009).

Figure 1
Thermal Stability and Cyclic Sealing Performance of Glass Composite Seals
Authors: Kim Taeyul , Park Sung , Lee Jae Chun
Published: February 2020

Glass matrix composites as sealing materials for solid oxide fuel cells (SOFCs) were prepared with Al2O3 and/or 8 mol % Y2O3-stabilized zirconia (8YSZ) fillers. Their thermal stability was evaluated by measuring thermal expansion coefficients (TECs) after heat-treatment in the 700~790°C range for 500 hours. With a glass composite containing ~2% closed porosity, and 10 vol% of Al2O3 and 8 YSZ fillers, the TEC change was 2% after heat-treatment at 750°C for 500 h. The TEC change of a base glass was as low as 1% after heat-treatment at 730°C for 500 h, demonstrating superior thermal stability of the base glass. Meanwhile, a glass composite containing ~10% closed porosity, and 10 vol% of Al2O3 fillers, the TEC change was as high as 8% after heat-treatment at 700°C for 500 h. The high thermal expansion of the porous glass composite containing Al2O3 filler could be understood considering the effect of porosity on the thermal expansion coefficient of porous materials. Thermal stability of the glass composite containing 10 vol% of Al2O3 and 8 YSZ fillers was further investigated with long-term cyclic sealability. The glass composite to STS444 seal assemblies was subjected to thermocycling between 450°C and 750°C, and survived over 14,000 h of 37 consecutive cycles. The leakage rates during thermal cycles were below 0.004 sccm cm−1 at seal operating temperature of 750°C. In summary, glass composites with mixed fillers of Al2O3 and 8YSZ showed superior thermal stability and cyclic sealing performance required for SOFC sealing materials. In this presentation, we will discuss the effect of the two different fillers on the thermal stability of glass matrix composites.
Single-Atoms As the Active Site with High Selectivity for Electrochemical Application
Authors: Xu Haiping , Xu Tao , Liu Di-Jia
Published: February 2020

Single-atom catalysts (SACs) are recently emerging as a new frontier in heterogenous catalysis for their effectiveness in promoting catalytic reactions. We report herein the study of carbon-supported SACs synthesized by a novel method that exhibit distinctive selectivity in electrochemical synthesis. The aberration-corrected HAADF-STEM images combined with X-ray absorption spectroscopy identified the presence of single atoms. Theoretical density functional theory simulations of the best performing catalytic activity and selectivity could be attributed to the existence of single atoms in the catalysts.
Novel Synthesis of [2,3] Naphthaloporphyrins
Authors: Kumar Siddhartha , Webre Whitney , Stewart Courtney , D'Souza Francis , Wang Hong
Published: February 2020

Polycyclic aromatic hydrocarbons such as tetracene, pentacene and their derivatives have been of immense interest to chemists because of their unique electronic properties such as high charge mobility and semiconductor like properties. Derivatives of various acenes have been used to fabricate OFET devices. Appending such acene moieties to porphyrin molecules at the 2,3 C-C bond of the porphyrin molecule gives rise to pi-extended acenes. The absorbance of such acenes are red-shifted compared to the parent porphyrins because of extended conjugation. Devices containing porphyrin based acenes should also be modulated by light in addition to an electrical impulses, which should help in areas such as signal processing.

One of the main problems faced by chemists is to synthesize diversely functionalized [2,3] naphthaloporphyrins, which in turn could be further functionalized to give higher acenes. Towards this goal we introduce a new method to synthesize [2,3] naphthaloporphyrins and their push pull derivatives.

Figure 1
Development of Adsorptive Membrane for Removal and Reclamation of Chromium from Tannery Wastewater
Authors: Hussain Fayyaz Salih
Published: February 2020

Municipal, business and agricultural activities can generate pollution, which is highly risk to health and may drive serious pollutants to soil, air and water environments if not captured or neutralized before released to the surroundings. Access to the clean water is a global problem for all living organism to sustain their healthy life. Less than 1% of the world’s fresh water is available for human consumptions. Huge quantity of fresh water is consuming in domestic, industrial and agricultural sector i.e 8, 22 and 72% respectively as a result large amount of wastewater contains enormous number of contaminants are dumping religiously into fresh water bodies. The important types of aquatic contaminants are dyes and toxic metal pollutants, which once entered in water and make unsuitable for desired use. Chromium enters environment through mining, various industrial processes and certain geological processes. Its removal is crucial to save plants and aquatic life. Due to its toxic and carcinogenic nature efficient removal technologies and materials are continuously investigated, these techniques are based on distillation or evaporation, coagulation, precipitation, electrolysis, ion change and adsorption. Adsorbents based totally on petro-derived artificial polymers, agri-wastes, fly ashes, and mineral-based total zeolites and goethites also are getting used for removal of chromium. Keratins, predominantly found in wool, human hair and nails, horns and feathers, are cysteine-rich proteins with sturdy mechanical residences, thermal sturdiness and resistance to physicochemical degradation.

The aim of this work is to synthesize and characterize a sponge from waste generated form tannery industry (wool) to remove and reclaim chromium. Keratin solution was extracted by using L-Cysteine, Urea under basic condition this solution was dialyzed, lyophilized and crossed linked to form a sponge, the sponge was characterized by using SDS-PAGE, FTIR, SEM, BET, CHNS. Atomic Absorption Spectroscopy is used for adsorption and removal of chromium at concentration 100mg/L. Spongy adsorbent prepared from waste material (leather wool) was successfully prepared and showed tremendous potential for removal of chromium from industrial wastewaters.
Development of a Photocatalytic Cellulose Nanocomposite Media for Organic Pollutant Degradation
Authors: Baker Samuel James , Tabert Jessica Lydia , Keleher Jason J.
Published: February 2020

Common remediation methods have employed adsorptive processes to effectively remove organic pollutants and improve water quality. While these methods provide significant improvement the complete removal and subsequent degradation has emerged as a critical area of process development. There has been a shift towards the development of photocatalytic media that contain strong adsorption capacity coupled with chemical degradation functionality to enhance the complete remediation of persistent organic pollutants. One such example is the incorporation of photocatalytic semiconducting nanoparticles (NPs), such as zinc oxide (ZnO) or titanium dioxide (TiO2), due to their strong light absorption within the UV region. The photoactivity of these NPs can be shifted into the visible region by functionalizing the surface with macromolecular visible light photon acceptors (congo red) or metal nanoparticles to form core-shell NPs with reduced band-gap energy. This study focuses on the development of a cellulose-based polymeric matrix that contains functionalized core-shell NPs to optimize the visible light activity. More specifically, the synthesis and characterization of Au nanoparticle (GNP) functionalized metal oxides were explored and embedded into the cellulose nanocomposite to enhance the degradation of persistent organic pollutants such as methylene blue and Roundup®. Initial results reveal that the embedding GNP improves simulated pollutant remediation (20%) under visible light irradiation. Additionally, a correlation between core-shell nanoparticle properties (size, precursor concentration, and band-gap energy) has shown to be a major driver in the modulation of remediation efficiency.