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Electrochemical Behaviour

Manickam Minakshi, Heidy Visbal, David R G Mitchell, Maximilian Fichtner
Bio-waste in the form of chicken eggshells, which contain high amounts of calcium carbonate (CaCO3), is used to store energy. The fine eggshell powders are used as an electrode against a metallic lithium anode in a non-aqueous electrolyte. The initial discharge capacitance of the eggshell system was found to be 232 F g-1, while the reversible capacitance was 120 F g-1. Thereon, the cell maintained an excellent capacitance retention of 92% over 1000 cycles. The electrochemical performance obtained is comparable to that of commercially available classical activated carbon (AC) material...
October 15, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Xuerui Tian, Lin Hou, Jiaojiao Wang, Xing Xin, Heng Zhang, Yuanyuan Ma, Yali Wang, Lina Zhang, Zhangang Han
New Na-bridged phosphomolybdates (H2en)12[{Na0.8K0.2(H2O)}2{Na[Mo6O12(OH)3(HPO4)2(PO4)2]2}2]·7H2O (1), (H2bpp)2[{Sr2(H2O)4}{Na3(H2O)10}{Na[Mo6O12(OH)3(HPO4)3(PO4)]2}]·2H2O (2), and (H2bpp)6 [{Ca2(H2O)4}{Na2(H2O)4}{Na[Mo6O12(OH)3(HPO4)3(PO4)]2}2] (3) (en = ethylenediamine, bpp = 1,3-bi(4-pyridyl)propane), were synthesized by a hydrothermal method and characterized. Single-crystal X-ray diffraction analysis revealed that the three hybrids were composed of fully reduced 'hourglass-shaped' {Na[PV4MoV6X31]2}n- (X = O/OH) clusters and N-containing organic cations...
October 11, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Hongduo Lu, Sture Nordholm, Clifford E Woodward, Jan Forsman
A new three-parameter (valency, ion size, and charge asymmetry) model, the asymmetric restricted primitive model (ARPM) of ionic liquids, has recently been proposed. Given that ionic liquids generally are composed of monovalent species, the ARPM effectively reduces to a two-parameter model. Monte Carlo (MC) simulations have demonstrated that the ARPM is able to reproduce key properties of room temperature ionic liquids (RTILs) in bulk and at charged surfaces. The relatively modest complexity of the model raises the possibility, which is explored here, that a classical density functional theory (DFT) could resolve its properties...
May 21, 2018: Journal of Chemical Physics
T Stettner, P Huang, M Goktas, P Adelhelm, A Balducci
Ionic liquids (ILs) have been proven to be promising electrolytes for electrochemical energy storage devices such as supercapacitors and lithium ion batteries. In the last years, due to deficiency in storage of lithium on earth, innovative systems, such as sodium-based devices, attracted considerable attention. IL-based electrolytes have been proposed also as electrolytes for these devices. Nevertheless, in the case of these systems, the advantages and limits of IL-based electrolytes need to be further investigated...
May 21, 2018: Journal of Chemical Physics
Nahla A Abdelshafi, Jérémy Bell, Knut Rurack, Rudolf J Schneider
Quick but accurate testing and on the spot monitoring of cocaine in oral fluids and urine continues to be an important toxicological issue. In terms of drug testing, a number of devices were introduced into the market within the last decades, notably for workplace inspection or roadside testing. However, these systems did not always fulfill the requirements in terms of reliability, especially when low cut-off levels are required. With respect to surface water, the presence of anthropogenic small organic molecules such as prescription and over-the-counter pharmaceuticals as well as illicit drugs like cannabinoids, heroin or cocaine have become a challenge for scientists to develop new analytical tools for screening and on-site analysis because many of them serve as markers for anthropogenic input and consumer behaviour...
October 4, 2018: Drug Testing and Analysis
Pavel M Usov, Chanel F Leong, Bun Chan, Mikihiro Hayashi, Hiroshi Kitagawa, Joshua J Sutton, Keith C Gordon, Idan Hod, Omar K Farha, Joseph T Hupp, Matthew Addicoat, Agnieszka Beata Kuc, Thomas Heine, Deanna M D'Alessandro
The stimuli responsive behaviour of charge transfer donor-acceptor metal-organic frameworks (MOFs) remains an understudied phenomenon which may have applications in tuneable electronic materials. We now report the modification of donor-acceptor charge transfer characteristics in a semiconducting tetrathiafulvalene-naphthalene diimide-based MOF under applied electrochemical bias and pressure. We employ a facile solid state in situ Raman spectroelectrochemical technique, applied for the first time in the characterisation of electroactive MOFs, to monitor the formation of a new complex TTFTC˙+-DPNI from a largely neutral system, upon electrochemical oxidation of the framework...
October 17, 2018: Physical Chemistry Chemical Physics: PCCP
Shunling Li, Lei Li, Qing Qu, Yaxin Kang, Baolin Zhu, Datao Yu, Rui Huang
Here, a heterogeneous Bacillus cereus (B. cereus) biofilm on the surface of 316 L stainless steel (SS) was observed. With electrochemical measurement and surface analysis, it was found that B. cereus biofilm could inhibit SS pitting corrosion, attributing to the blocking effect of bacterial biofilm on extracellular electron transfer (EET). Differential pulse voltammetry (DPV) and cyclic voltammetry (CV) results also showed that B. cereus biofilm clearly impeded the EET. The proposed mechanism for the decreased corrosion rates of SS involves the interactions of extracellular polymeric substance (EPS) with SS and biofilm formation blocking electron transfer, preventing the passive layer from destroying...
September 25, 2018: Colloids and Surfaces. B, Biointerfaces
Jaroslav Fojt, Michaela Fousova, Eva Jablonska, Ludek Joska, Vojtech Hybasek, Eva Pruchova, Dalibor Vojtech, Tomas Ruml
3D printing seems to be the technology of the future for the preparation of metallic implants. For such applications, corrosion behaviour is pivotal. However, little is published on this topic and with inconsistent results. Therefore, we carried out a complex study in which we compared two techniques of the 3D printing technology - selective laser melting and electron beam melting. The corrosion behaviour was studied in physiological solution by standard electrochemical techniques and susceptibility to localised corrosion was estimated too...
December 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Sinead Murphy, Flavien Ivol, Alex R Neale, Peter Goodrich, Fouad Ghamouss, Christopher Hardacre, Johan Jacquemin
This work provides a study based on acyclic and cyclic sulfonium ionic liquids (ILs) with alkyl and ether-functionality on the cation paired with the bis{(trifluoromethyl)sulfonyl}imide, [TFSI]-, or the bis(fluorosulfonyl)imide, [FSI]-, as the counter anion. Herein, thermophysical characterisation of nine sulfonium-based ILs concerning the density, viscosity and conductivity and thermal properties including phase transition behaviour and decomposition temperature is reported. The electrochemical stability of the ILs was also measured by cyclic voltammetry at a glassy carbon macro-disk electrode...
September 25, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Ganesan Kumaravel, Ponya Utthra Ponnukalai, Dharmasivam Mahendiran, Natarajan Raman
This work deals with a series of biologically important novel transition metal(II) Schiff base chelates containing terpyridine. Benzimidazole, a moiety found in broad spectrum of drugs is espoused in a Schiff base ligand system. Eight such metal(II) complexes are designed, synthesized and characterized. An octahedral geometry has been envisaged for all the complexes. DNA-binding behaviours are studied by absorption titration, electrochemical, viscosity, fluorescence and circular dichroism methods. The DNA cleavage ability is also evaluated by agarose gel electrophoresis method...
September 20, 2018: International Journal of Biological Macromolecules
Axel Haupt, Dieter Lentz
Corannulene is a multifaceted polyaromatic compound. It has many interesting properties, for example a bowl-shaped molecular structure which in addition undergoes a dynamic inversion process. It gained a lot of attraction within the last decades. This is not only due to its structural, but also its electronic properties and finally its various potential applications in materials chemistry. Herein, we summarize on the synthetic approaches towards corannulene derivatives with electron-withdrawing substituents...
September 20, 2018: Chemistry: a European Journal
Yingtian Zhang, Shuxian Yu, Peipei Luo, Shisong Xu, Xianxi Zhang, Huawei Zhou, Jiyuan Du, Jie Yang, Nana Xin, Yuxia Kong, Junhai Liu, Baoli Chen, Jiaxing Lu
Resulting from the drastic increase of atmospheric CO2 concentration day by day, global warming has become a serious environmental issue nowadays. The fixation of CO2 to obtain desirable, economically competitive chemicals has recently received considerable attention. This work investigates the fixation of CO2 along with three bromopyridines via a facile electrochemical method using a silver cathode to synthesize picolinic acids, which are important industrial and fine chemicals. Cyclic voltammetry is employed to investigate the cyclic voltammetric behaviour of bromopyridines...
August 2018: Royal Society Open Science
Alexandra Verhaven, T Doneux, D Bizzotto
Immobilized DNA probe strands self-assembled on an electrode surface are the bases of many electrochemically based biosensors. Control or measurement of the local environment around each DNA molecule tethered to the electrode surface is needed because the local environment can influence the binding or hybridization efficiency of the target in solution. Measurement of this local environment in buffer or under electrochemical control can be challenging. Here we demonstrate the use of fluorescence microscopy and a Förster resonance energy transfer (FRET) methodology to characterize multicomponent DNA SAMs...
September 20, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
B Jerliu, E Hüger, L Dörrer, B K Seidlhofer, R Steitz, M Horisberger, H Schmidt
Operando neutron reflectometry measurements were carried out to study the insertion of lithium into amorphous silicon film electrodes during cyclic voltammetry (CV) experiments at a scan rate of 0.01 mV s-1. The experiments allow mapping of regions where significant amounts of Li are incorporated/released from the electrode and correlation of the results to modifications of characteristic peaks in the CV curve. High volume changes up to 390% accompanied by corresponding modifications of the neutron scattering length density (which is a measure of the average Li fraction present in the electrode) are observed during electrochemical cycling for potentials below 0...
September 19, 2018: Physical Chemistry Chemical Physics: PCCP
Filipa O Gomes, Luísa B Maia, Cristina Cordas, Isabel Moura, Cristina Delerue-Matos, José J G Moura, Simone Morais
Understanding the direct electron transfer processes between redox proteins and electrode surface is fundamental to understand the proteins mechanistic properties and for development of novel biosensors. In this study, nitric oxide reductase (NOR) extracted from Marinobacter hydrocarbonoclasticus bacteria was adsorbed onto a pyrolytic graphite electrode (PGE) to develop an unmediated enzymatic biosensor (PGE/NOR)) for characterization of NOR direct electrochemical behaviour and NOR electroanalytical features towards NO and O2 ...
August 21, 2018: Bioelectrochemistry
Andrei Ionut Mardare, Cezarina Cela Mardare, Jan Philipp Kollender, Silvia Huber, Achim Walter Hassel
A thin film combinatorial library deposited by co-sputtering of Hf, Nb and Ta was employed to characterise fundamental properties of the Hf-Nb-Ta system. Compositional mappings of microstructure and crystallography revealed similarities in alloy evolution. Distinct lattice distortion was observed upon addition of hexagonal Hf, leading to amorphisation of alloys containing more than 32 at.% Hf and less than 27 and 41 at.% Nb and Ta, respectively. Volta potential and open circuit potential mappings indicated minimal values for the highest Hf concentration...
2018: Science and Technology of Advanced Materials
Cheng Ma, Wanwan Wu, Lingling Li, Shaojun Wu, Jianrong Zhang, Zixuan Chen, Jun-Jie Zhu
The quest for new techniques to measure single nanomaterials is a great impetus to research efforts to understand individual behaviours. Here, we develop an electrochemiluminescence (ECL) microscopy for visualization of stochastic collision electrochemistry of single nano-emitters without the interference of current and optical background. This design uses a water-immersion objective to capture the ECL emission of nanoparticles near the specular electrode surface for enhancing light collection efficiency. The approach enables us to trace the collision trajectory of multiple nanoparticles and spatially distinguish simultaneous collisions...
August 7, 2018: Chemical Science
Maria L Ferreira, Silvana A Ramirez, Diana L Vullo
Siderophores are low-molecular weight ligands secreted by bacteria as a survival strategy in Fe(III)-lacking environments. They bind not only Fe(III), but Co(II), Zn(II), Mn(II), Ni(II), Ga(III) as a detoxification alternative. The synthesis, purification and characterization of siderophores produced by Pseudomonas veronii 2E were evaluated to be applied in future environmental technologies. Optimal production was obtained in Fe(III)-free M9-succinate at 25 °C, 40 h and pH 6.9. Siderophores were chemically characterized as hydroxamate and catechol mixed-type...
August 17, 2018: World Journal of Microbiology & Biotechnology
Almudena Benítez, Marcos González-Tejero, Álvaro Caballero, Julián Morales
A microporous carbon derived from biomass (almond shells) and activated with phosphoric acid was analysed as a cathodic matrix in Li⁻S batteries. By studying the parameters of the carbonization process of this biomass residue, certain conditions were determined to obtain a high surface area of carbon (967 m² g-1 ) and high porosity (0.49 cm³ g-1 ). This carbon was capable of accommodating up to 60% by weight of sulfur, infiltrated by the disulphide method. The C⁻S composite released an initial specific capacity of 915 mAh g-1 in the Li⁻S cell at a current density of 100 mA g-1 with a high retention capacity of 760 mAh g-1 after 100 cycles and a coulombic efficiency close to 100%...
August 14, 2018: Materials
Sergey V Gnedenkov, Sergey L Sinebryukhov, Veniamin V Zheleznov, Denis P Opra, Elena I Voit, Evgeny B Modin, Alexander A Sokolov, Alexander Yu Ustinov, Valentin I Sergienko
Hafnium-doped titania (Hf/Ti = 0.01; 0.03; 0.05) had been facilely synthesized via a template sol-gel method on carbon fibre. Physico-chemical properties of the as-synthesized materials were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, scanning transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetry analysis and Brunauer-Emmett-Teller measurements. It was confirmed that Hf4+ substitute in the Ti4+ sites, forming Ti1- x Hf x O2 ( x  = 0...
June 2018: Royal Society Open Science
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