bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbon Paste Biosensors Modified with Titanium Dioxide Nanoparticles for the Determination of Acids, Antioxidants and Glucose in Grapes
Authors: Garcia-Cabezon Cristina , Muñoz Raquel , Garcia-Hernandez Celia , Medina-Plaza Cristina , Blanco-Val Yolanda , de Saja Jose Antonio , Martin-Pedrosa Fernando , Rodriguez-Mendez Maria Luz 
Published: February 2020

The use of quick, reliable and cheap sensors for the detection of chemical compounds represents an important need in the wine sector. Among the analytes that must be monitored and measured in order to guarantee the quality of final products and to verify that industrial processes are under control, glucose, phenolic compounds and acidity are the most important. Previous works have demonstrated that voltammetric electrodes chemically modified with electrocatalytic materials such as phthalocyanines or gold nanoparticles can be used to detect such compounds in musts and wines [1]
Titanium dioxide nanoparticles TiO2 NPs have attracted much attention as catalyst support because of their large specific surface area, favorable surface chemistry, good biocompatibility, and electrocatalytic activity [2]. In this work carbon paste electrodes (CPE) modified with TiO2 NPs have been developed and used to analyze those components usually needed to establish the quality of grapes.
For this purpose, after optimization of the preparation method (proportion of TiO2, drying conditions, activation, etc), the electrochemical response toward organic acids (malic, vanillic and tartaric) and antioxidants (gallic acid and catechol) was evaluated.. It was demonstrated that the modified electrode produced higher peak currents than those achieved at carbon electrode alone, improving the detection limits. The linear range for the determination of phenolics and acids was in the range of 10−6 M at a signal-to-noise ratio of 3. The stability and repeatability of the biosensor was also discussed.
Biosensors consist of carbon paste modified with TiO2 nanoparticles combined with glucose oxidase was used to determine glucose. Similarly, the TiO2 electrodes were used to immobilize tyrosinase to detect phenolic compounds The results showed that the modified biosensor was sensitive and stable in detecting glucose, indicating that TiO2 nanoparticles was a good candidate material for the immobilization of enzyme in glucose biosensor construction. Therefore the autocatalytic role of TiO2 nanoparticles was demonstrated on voltammetric sensors and biosensors. Finally, modified sensors and biosensors was applied to analysis of musts and allowed quantification of the acid and antioxidant capacity of the tested musts.
References
[1] C. Medina-Plaza, J.A. de Saja, M.L. Rodriguez-Mendez (2014) Biosensors and Bioelectronics 57, 276.
[2] S. Ashok Kumar, Po-Hsun Lo, Shen-Ming Chen 2008, Nanotechnology 19, 255501
Figure 1. Voltammetric cyclic of graphite sensor (dotted line) and modified TiO2 NPS sensor (solid line) on catechol 10-3 mol.L-1 .

Figure 1
Influence of pH on Morphology and Electro-Activity of Ternary Pt-Co-P/MWCNT Electro-Catalysts Towards Methanol Electro-Oxidation
Authors: Sun Junting , Wang Feng , Dou Meiling , Liu Jingjun 
Published: February 2020

Methanol is widely investigated as anodic reactant in direct methanol fuel cell (DMFC) for its character of clean, convenient, and high theoretical density when compared with traditional fossil fuel and hydrogen. However, the sluggish kinetics of the methanol oxidation reaction (MOR) promotes the investigation of electrocatalysts to improve the reaction efficiency of the MOR process. Platinum is developed as the best catalysts for the MOR process, but poor anti-poisoning ability and the high cost severely limit its applications. Recent studies show that the amorphous metallic nanoparticles hold much promise for use as catalyst because of the surface-rich low-coordinate site, which could act as active site for catalyst [1].it was found that the incorporation of P into metallic alloy could form amorphous structure and lower the size of the nanoparticles, both of which are in favor of high electro-catalytic efficiency. Besides, the abundant valence electrons of phosphorous shows influence on magnetic and electro-catalytic properties of the metallic nanoparticles [2].
In this abstract, four supported Pt-based electro-catalysts prepared through impregnation method at different pH values were introduced for MOR. The difference of pH values for composition and crystallization of each electro-catalysts and their electro-catalytic activity was investigated through analyzing X-ray diffraction spectra (XRD), high-resolution transmittance electron micrograph (HRTEM), and cyclic voltammetry curves (CV). The XRD patterns show four obvious widening of diffraction peaks with the increase of pH value which indicates the decrement of particle size and the results are in accordance with our previous investigation. The CV tests show that the electro-catalyst prepared in high pH value perform a relatively high MOR activity comparing with others prepared in lower pH. The promotion of electro-catalytic activity for MOR is mainly due to the diminish of the particle size of electro-catalyst in high pH value which produce low-coordinate site on the surface of nanoparticle. The low-coordination sites show stronger adsorption towards small molecules which facilitate electro-oxidation of methanol on Pt-Co-P electro-catalyst.

Figure 1
Hybrid Bilayer Membrane As a Versatile Electrochemical Platform to Modulate Transport Kinetics of Small Molecules Across a Lipid Monolayer
Authors: Barile Christopher J. , Tse Edmund C. M. , Kirchschlager Nicholas A. , Li Ying , Zimmerman Steven C. , Hosseini Ali , Gewirth Andrew A. 
Published: February 2020

We report our effort to gate molecular transport through lipids. To probe the kinetics of small molecule delivery in and out of a lipid layer, we monitored the electrochemical response of a redox-active moiety covalently attached to a self-assembled monolayer (SAM) on gold. We prepared the first synthetic dicopper electrocatalyst (CuBTT) on a SAM/Au system for the oxygen reduction reaction (ORR) through rational design based on an aminotriazole derivative discovered previously by our group. The kinetically sluggish ORR proceeds via multiple proton-coupled electron transfer (PCET) steps. By appending a monolayer of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) on top of a CuBTT-SAM to construct a hybrid bilayer membrane (HBM, Figure 1), we suppressed the ORR activity of CuBTT. This inhibition in ORR activity is due to the hydrophobic lipid interior which impedes transmembrane diffusion of the hydrophilic positively-charged protons.
In nature, membrane-bound proton carriers deliver protons across lipid bilayers via flip-flop diffusion. Inspired by biological systems, we recovered the ORR activity of CuBTT by incorporating an alkyl phosphate, mono-N-dodecyl phosphate (MDP), in the lipid monolayer of the HBM to facilitate proton transfer to CuBTT. We further discovered that this assisted proton transport behavior can be turned on and off by switching the pH of the bulk solution. This observation allowed us to build a pH-sensitive switch that modulates proton flux to a HBM-embedded ORR electrocatalyst.(1) We believe this HBM platform not only can provide valuable mechanistic insight into PCET reactions, but also lay the foundation for advanced bio-compatible electronics and nanocomputers.
The HBM electrochemical platform allows for the precise and independent control of both the thermodynamics and kinetics of proton transfer to a molecular catalyst. We are in the process of understanding the underlying mechanism of the assisted proton transfer process and in search of a quantitative structure-activity relationship between different proton carriers. Apart from studying related HBM platforms with different lipids and proton carriers, embedding redox and pH markers inside a HBM will provide valuable information about the internal environment of the system. We are also interested in controlling the kinetics of other small molecules through the lipid layer, which offers a unique electrochemical platform for drug screening processes.
References
1. C. J. Barile, E. C. M. Tse, Y. Li, T. B. Sobyra, S. C. Zimmerman, A. Hosseini and A. A. Gewirth, Nat. Mater., 13, 619 (2014).

Figure 1
A Novel Real-Time, Mediator-Free, Non-Enzymatic Electrochemical Biosensor for Glutamate Detection
Authors: Yang Yu-Ping , Manfredi Anita , Daunert Sylvia 
Published: February 2020

Glutamate is the major excitatory neurotransmitter in the brain, and an excess of glutamate can cause excitotoxicity, which is a common pathological process in many neurologic disorder such as stroke, brain trauma, and brain tumor. Therefore, monitoring glutamate in real time is of critical importance. However, the existing methods for the detection and monitoring glutamate levels are limited. Here in this work, we present a novel mediator-free, non-enzymatic electrochemical biosensor for real-time glutamate monitoring, based on immobilization of genetically engineered periplasmic glutamate binding protein onto gold nanoparticle-modified screen-printed carbon electrodes. Cyclic voltammetry is performed to determine the glutamate concentration in phosphate buffer solution (pH=7.4). The results show an excellent sensitivity with 0.1µM detection limit and the linearity was investigated in the 0.1µM-1µM range of glutamate concentration. The sensor was tested with common interfering substances such as aspartate, glutamine, serine, lysine and ascorbic acid, and exhibited high selectivity toward glutamate over those substances.

Figure 1
Anion Transport Across Electrode-Supported Lipid Membranes
Authors: Tse Edmund C. M. , Barile Christopher J. , Gewargis John P. , Li Ying , Zimmerman Steven C. , Gewirth Andrew A. 
Published: February 2020

We use a hybrid bilayer membrane as an electrochemical platform to study anion diffusion through a lipid monolayer. We first append lipid on a self-assembled monolayer that contains a covalently-bound Cu(I)/Cu(II) redox center. We then perform cyclic voltammetry using different anions in bulk solution and extract thermodynamic and kinetic information about anion transport. The voltammetry is affected by the scan rate and the identity of the anions, but not the bulk anion concentration. An increase in scan rate causes the HBM system to switch from a diffusionless regime to one controlled by anion diffusion. In the latter regime, we test six anions that exhibit a wide range of cathodic peak potentials and cathodic-anodic peak separation values, which reflect the differences in the thermodynamics and kinetics of anion diffusion across the lipid membrane.
We analyze the results using factor analysis and determine that anion transport quantitatively correlates to polarity and basicity, a relationship we formalize as the lipid permeability parameter. In addition, we discuss how our findings can be interpreted according to the two leading mechanisms describing ion permeability through lipids. Our results demonstrate that anion transport in a HBM is best described by the solubility-diffusion mechanism, not the pore mechanism.

Figure 1
High-Performance SOFC Electrodes Synthesized By Novel One-Step Chemical Routes
Authors: Martinelli Antonio Eduardo , Macedo Daniel Araujo , Cesário Moises Romolos , Paskocimas Carlos Alberto , Fagg Duncan Paul , Nascimento Rubens Maribondo 
Published: February 2020

The next generation of hydrogen-operated solid oxide fuel cells (SOFCs) will most certainly rely on high-performance ceramic and composite electrode materials manufactured from optimized routes. La0.6Sr0.4Co0.2Fe0.8O3-Ce0.8Sm0.2O1.9 (LSCF-SDC, 50 wt.% SDC) and NiO-CGO (50 wt.% NiO) composite powders, usually employed to prepare SOFC electrodes, were synthesized by two novel one-step synthetic routes, namely microwave-assisted combustion and a modified polymeric precursor method, respectively. Powder characterization was carried out by XRD and TEM. Screen-printed electrodes with different microstructures, evaluated by scanning electron microscopy, were obtained on CGO pellets. The electrochemical performances for the hydrogen oxidation and oxygen reduction reactions were investigated by impedance spectroscopy in the temperature range of 650-750 °C using flowing humidified 10% H2 + 90% N2 gas mixtures for the anodes and pure oxygen for the cathodes. By using a three-electrode configuration cell, dc polarization measurements were also performed on selected electrodes. The results of the electrochemical characterization indicated a significant dependence of the area specific resistance (ASR) on the electrode microstructure, highlighting that the electrode resistance can be manipulated by microstructural design. The best ASR values obtained at 750 °C in pure oxygen (cathode) and hydrogen atmosphere (anode) were found to be 0.18 and 0.15 ohm.cm2, respectively. The one-step Ni-CGO electrode with improved microstructure showed an anodic overpotential of 91 mV at 750 °C for a current density of 322 mA/cm2, which is amongst the best results mentioned in the literature, demonstrating that the novel one-step synthesis routes are innovative chemical ways to prepare promising SOFC electrodes.
Effect of Nano-Silver Ink Composition and Drying Behavior on Its Adhesion on Glass Substrate
Authors: Lai I-Hsien , Chou Kan-Sen 
Published: February 2020

The adhesion of silver colloids to a glass substrate was investigated in this study.
The silver colloids first added nano-TiO2 particle by varying solid content and changed pH to 10 to make sure the solution dispersion well. The adhesion of silver colloids to the glass substrate after sintering was then measured according to both ASTM D4541 and ASTM 3359 standards. The results indicated that adhesion increased proportionally with TiO2 solid content; however, this enhancement effect was lessened when the solid content was above 8wt%. Sintering temperature was also beneficial in increasing adhesion to the substrate; however, the electrical resistance of the silver colloids after sintering increased with degree of solid content. This implied that TiO2 solid content simultaneously made adhesion and electrical resistance increased. Consequently, values of TiO2 solid content and sintering temperature were optimal when adhesion and electrical resistivity were balanced. Ultimately, using commercial software Origin to fit the TiO2 solid content and sintering temperature to get the optimum value of adhesion and electrical resistivity.
Electric-Arc Synthesis of New and Uncommon Endohedral Metallofullerenes
Authors: Kime Brittany L , Stevenson Steven 
Published: February 2020

During the last 30 years, minimal research has been successful for entrapping elements beyond the more common Sc, Y, La and 4f-block lanthanide metals. Our goal is to expand the selection of metals that can be encapsulated. Preliminary results indicate that new metallofullerenes can be produced successfully with our electric-arc, plasma reactor. Key experimental parameters were metal selection, buffer gas, gap voltage, amount of current, chamber pressure, burn time, flow rate of added gases, and choice of chemically reactive atmosphere. By manipulating these variables, we have produced new clusters in addition to conventional clusters in uncommon cages. Upon their successful synthesis, efforts are currently underway to separate and isolate these new molecules utilizing non-chromatographic methods.
Carbon Nanodots - Towards a Comprehensive Understanding of Their Photoluminescence
Authors: Guldi Dirk M. 
Published: February 2020

For the first time, a comprehensive report on the characterization carbon nanodots (CND), a novel class of nanocarbons is given. Our microwave reactor synthesis provides mild and controlled conditions that afford CNDs with homogeneous and narrowly dispersed optical properties. As such, they are well suited as a testbed for studies of the photophysics of carbon-based nanoscopic emitters, including electron transfer studies. Our experimental work includes steady-state investigations, time-correlated single-photon counting, fluorescence up-conversion, and transient pump-probe absorption spectroscopy. It is rounded off by density-functional theory and semiempirical configuration-interaction calculations that provide significant additional insight. This all leads to a sound understanding of the fundamental structure-property relationships for this novel type of material.
Chemically Functionalized Nanocarbons for Artificial Photosynthesis and Solar Energy Conversion
Authors: Imahori Hiroshi 
Published: February 2020

Recently, we have conducted the regioisomer separation of hexyloxycarbonyl-substituted dihydronaphthyl-based [60]fullerene bis-adducts (C6BA) and applied the separated bis-adducts to PSCs for the first time.1,2 To reduce the plausible number of the fullerene bis-adduct isomers, a symmetrical dihydronaphthyl group was chosen as the substituent. We expected that symmetrical introduction of two long alkoxycarbonyl chains into the dihydronaphthyl groups would facilitate the isomer separation and purification. Indeed, repeated separations by HPLC equipped with a Buckyprep column afforded trans-1, trans-2, trans-3, trans-4, e, and a mixture of cis-2 and cis-3 (denoted as cis-2+cis-3) isomers. The LUMO energy levels of C6BA isomers estimated by cyclic voltammetry are 0.1 – 0.2 eV higher than those of the corresponding mono-adduct (C6MA) and [60]PCBM. However, the best PCE (1.44%) achieved by the trans-4 isomer of C6BA (denoted as C6BA–trans-4) in combination with regioregular poly(3-hexylthiophene) (P3HT) was lower than those of the corresponding mono-adduct C6MA and [60]PCBM-based PSCs (1.71 and 2.10%, respectively). The inferior efficiencies may be caused by the long aliphatic side chains, which disrupt the optimal packing and efficient electron transport of the fullerene molecules in the active layer. Hence, we decided to shorten the n-hexyl chain of C6BA to n-butyl and ethyl (C4BA and C2BA). We expected that we could systematically address the effects of alkyl chain length as well as substituent pattern of fullerene bis-adducts on the photovoltaic properties of PSCs.3 In this talk I will present an overview of our chemically functionalized nanocarbons for artificial photosynthesis and solar energy conversion.
[1] S. Kitaura, K. Kurotobi, M. Sato, Y. Takano, T. Umeyama, and H. Imahori, Chem. Commun., 48, 8550-8552 (2012).
[2] T. Umeyama and H. Imahori, J. Mater. Chem. A (Feature Article), 2, 11545-11560 (2014).
[3] R. Tao, T. Umeyama, K. Kurotobi, and H. Imahori, ACS Appl. Mater. Interface, in press.
Effect of Displacement Deposition on Platinum Deposition within Nanoporous Silicon
Authors: Koyama Akira , Fukami Kazuhiro , Koda Ryo , Sakka Tetsuo , Abe Takeshi , Kitada Atsushi , Murase Kuniaki 
Published: February 2020

In the use of nanoporous electrode, the control of mass transfer within nanopores is crucially important to elicit their best performance. However, mass-transfer rate for ionic species through electrolyte solution within nanopores tends to be very low, so that only a limited proportion of the whole specific surface area contributes to electrochemical reactions. In the case of the metal filling within the porous silicon by electrodeposition, poor supply of metal precursor into the nanopores also causes a problem to induce a plugging at the pore opening. We have investigated the pore filling with platinum in an aqueous solution with tuning the hydration property of the surface of pore wall and platinum complex anions [1-3]. The important insight we have found is the surface-induced phase transition (SIFT: the concentration of the hydrophobic solutes near the hydrophobic surface becomes orders of magnitude higher than that in the bulk) in the nanopores plays an important role in electrodeposition of platinum within the nanoporous silicon. Our previous reports, however, focused only on the presence of platinum deposits in the porous layer corresponding to the various experimental conditions and didn’t elucidate the dynamic aspects of the penetration of platinum complex anions into the nanopores. We adopted the time developments of the mixed-potential measured during the displacement deposition of platinum within the porous silicon to find the peculiar penetration dynamics that could not be understood within the framework of simple diffusion. One of the typical observations shows the penetration is faster when the pore diameter is smaller and the anion size is larger. In this paper, we also discuss the effect of the pore depth on the penetration dynamics.
[1] K. Fukami, R. Koda, T. Sakka, T. Urata, K. Amano, H. Takaya, M. Nakamura, Y. Ogata, and M. Kinoshita, Chem. Phys. Lett., 2012, 542, 99-105.
[2] K. Fukami, R. Koda, T. Sakka, Y. Ogata, and M. Kinoshita, J. Chem. Phys., 2013, 138, 094702.
[3] R. Koda, A. Koyama, K. Fukami, N. Nishi, T. Sakka, T. Abe, A. Kitada, K. Murase, and M. Kinoshita, J. Chem. Phys., 2014, 141, 074701.
Mechanism Study of Lithium Ion Insertion into Titania Nanotubes
Authors: Djenizian Thierry 
Published: February 2020

Lithium-ion batteries (LIBs) are widely used to power portable devices, microelectronics, and vehicles. With many advantages such as high surface area and improved charge transport, self-supported 3-D nanostructured metal oxides are promising electrode materials for LIBs and their impact is particularly significant when considering the miniaturization of energy storage systems and the development of 3D microbatteries [1-3].
During this talk, it will be presented the utilization of self-organized titania nanotubes (TiO2nts) as negative 3D self-supported electrode for Li-ion microbatteries [4–8]. This 3D nanostructured electrode is quite interesting owing to better electrochemical performance in terms of kinetics and stability.
Then, the fabrication of a all-solid-state battery composed of vertical arrays of TiO2nts as anode, a polymer thin film as electrolyte, and a high potential cathode material like LiNi0.5Mn1.5O4 (LNMO) layer will be shown [9] and the current approaches developed to achieve the fabrication of a full 3D microcell will be highlighted. Particularly, the conformal electrodeposition of polymer electrolyte into titania nanotubes [10] will be discussed as well as the improvement of the electrochemical performance.
Finally, the Li+ insertion into anatase titania nanotubes employing PEO-based polymer electrolyte studied by cyclic voltammetry and chronoamperometry will be presented. The study shows that the Li+ storage in the anatase is dominated by the bulk diffusion (into the lattice) and the increasing contribution of the pseudo-capacitive effect with faster kinetics We also report that the chemical diffusion of Li+ in self-organized titania nanotubes is around 2 × 10-16 cm2 s-1 suggesting that the use of a solid electrolyte does not alter the charge transport in the nanostructured electrode.
References
[1] B.L. Ellis, P. Knauth, T. Djenizian, Adv. Mater., 26 (2014) 3368.
[2] L. Baggetto, J.F.M. Oudenhoven, T. van Dongen, J.H. Klootwijk, M. Mulder, R. a. H. Niessen, M.H.J.M. de Croon, P.H.L. Notten, J. Power Sources 189 (2009) 402.
[3] M. Nathan, D. Golodnitsky, V. Yufit, E. Strauss, T. Ripenbein, I. Shechtman, S. Menkin, E. Peled, Microelectromechanical Syst. J. 14 (2005) 879.
[4] G. Ortiz, I. Hanzu, T. Djenizian, P. Lavela, J.L. Tirado, and P. Knauth, Chem. Mater. 21 (2009) 63.
[5] N.A. Kyeremateng, C. Lebouin, P. Knauth, T. Djenizian, Electrochim. Acta 88 (2012) 814.
[6] N.A. Kyeremateng, V. Hornebecq, P. Knauth, T. Djenizian, Electrochim. Acta 62 (2012) 192.
[7] T. Djenizian, I. Hanzu, P. Knauth, J. Mater. Chem. 21 (2011) 9925.
[8] N.A. Kyeremateng, N. Plylahan, A.C.S. dos Santos, L. V Taveira, L.F.P. Dick, T. Djenizian, Chem. Commun. 49 (2013) 4205.
[9] N. Plylahan, M. Letiche, M. Barr, and T. Djenizian, Electrochem. Commun., 43, 121 (2014).
[10] N. Plylahan, N.A. Kyeremateng, M. Eyraud, F. Dumur, H. Martinez, L. Santinacci, P. Knauth, T. Djenizian, Nanoscale Res. Lett. 7 (2012) 349.