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The current need for handheld electronic devices with high energy autonomy has amplified research into clean and mobile energy source developments. Among suitable and promising technologies for this application, fuel cells, FCs are highlighted because of their minimal emission of pollutants and high efficiency. One type of FCs that has yet to be studied is the hydrogen peroxide/direct hydrogen peroxide fuel cell (DPPFCs). The present work is dedicated to the development of DPPFCs of one compartment using copper hexacyanoferrates (CuHCFs) as cathodic material and a Ni grid as anodic material. CuHCFs containing FeII and/or FeIII were synthesized, characterized and their electrocatalyst performances were compared in 0.1 mol L−1 HCl and 0.5 mol L−1 H2O2. The maximum power densities reached for the CuFeII was 8.3 mW cm−2 and for the CuFeIIFeIII was 2.9 mW cm−2. The CuHCFs cathode materials show promising results, standing out as innovative materials for such an application.

Made available in DSpace on 2020-12-12T02:42:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-07-01 An easy and effective method for the preparation of a new impedimetric sensor used in the detection of dimethyl sulfide (DMS) at a nanomolar level is presented. The sensor was prepared in two steps from a commercially available screen-printed carbon electrode (SPCE): a simple activation of the SCPE using cyclic voltammetry followed by electroless plating of the working electrode surface with gold clusters. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) techniques confirmed the successful functionalization of the SPCE, revealing the presence of gold particles dispersed on the carbon matrix. Electrochemical impedance spectroscopy (EIS) was used to study the sensitivity of the sensor towards DMS dissolved in aqueous solution and simulated ocean water. Analyses were performed in less than 3 min, and the sensor showed linearity in a concentration range from 1.0 × 10−10 to 1.0 × 10−8 M with a limit of detection of 1.50 × 10−9 M and a limit of quantification of 2.27 × 10−9 M. To simulate the marine environment in which DMS is naturally present in nature, the impedance of the sensor was monitored by online EIS. Moreover, results indicated that, despite not linearly, the sensor is a promising tool to detect the analyte even at 1.0 × 10−11 M, presenting an increase of resistance of 13.5% in relation to its bare condition. Center for Optics Photonics and Lasers (COPL) Université Laval CDN Isotopes Department of Chemical Engineering Universidade Federal de Minas Gerais (UFMG) Laboratory of Applied Immunology Fundação Ezequiel Dias (FUNED) Department of Chemistry Universidade Federal de Minas Gerais (UFMG) Institute of Chemistry UNESP Institute of Chemistry UNESP

Made available in DSpace on 2020-12-11T17:02:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 Natural Sciences and Engineering Research Council of Canada (CRSNG) Canadian Funding for Infrastructure (CFI) Canada Excellence Research Chair in Photonics Innovations (CERCP) Screen-printed carbon electrode (SPCE) was examined as a transducer substrate for application in electrochemical sensors. Aqueous solutions of 0.1 M KCl and 0.1 M KCl + 5 mM K-3[Fe(CN)(6)]/K-4[Fe(CN)(6)] (redox solution) were prepared to simulate the environment of faradaic and non-faradaic sensing, respectively. The SPCE presented an irregular surface composed by two main carbon phases. Raman spectroscopy results revealed the presence of peaks around 1,580 cm(-1) and 1,334 cm(-1) related to the G and D bands corresponding to sp(2) carbon atoms (graphite flakes) and a multitude of broad bands associable to amorphous sp(3) carbon in the ink matrix. Conductive atomic force microscopy indicated that the irregular structure of the SPCE led to the heterogeneous distribution of the current over the surface and the electroactivity of this material was mainly attributed to the presence of graphite. Polarization curves and electrochemical impedance spectroscopy (EIS) revealed that the redox solution was more aggressive to the SPCE, despite this electrode was achieved a quasi-steady state for 1 h under the effect of a polarization potential in both electrolytes, which justifies its use as an electrochemical transducer in faradaic and non-faradaic devices. Univ Fed Minas Gerais UFMG, Dept Chem Engn, BR-30270901 Belo Horizonte, MG, Brazil Univ Laval, Ctr Opt Photon & Lasers COPL, Quebec City, PQ G1V 0A6, Canada Fundacao Ezequiel Dias FUNED, Dept Appl Immunol, BR-30510010 Belo Horizonte, MG, Brazil Univ Fed Minas Gerais UFMG, Dept Chem, BR-30270901 Belo Horizonte, MG, Brazil UNESP, Inst Chem, BR-14800060 Araraquara, SP, Brazil UNESP, Inst Chem, BR-14800060 Araraquara, SP, Brazil

In this work, two catalysts, lanthanum manganite strontium-doped perovskite without (LSM) and with (LSMMO) mixed molybdenum oxides, were synthesized by the sol-gel route and deposited by immersion in carbon cloth substrates. Their performance as cathodes in the hydrogen peroxide reduction reaction (HPRR) and oxygen reduction reaction (ORR) was investigated through cyclic voltammetry and electrochemical impedance spectroscopy, the electrocatalytic efficiency of these electrodes in the HPRR was analyzed in KOH and H2O2 medium at 298 K. The performance of the cathodes, in a single compartment, using a nickel plate as an anode was also investigated. The results showed that for the reduction reactions, electrodes developed with LSMMO have more significant catalytic activity than LSM after polarization, resulting in 32% higher current densities, lower electrical resistance after polarization, and a 21% increase in power density.

RESUMO Um dos desafios atuais é a busca de materiais eficientes e de baixo custo para os componentes das Pilhas a Combustível de Óxido Sólido (PaCOS), já que estes dispositivos se destacam pela geração limpa de energia elétrica e alta eficiência. Dentre estes componentes está o interconector, nos quais o aço inoxidável ferrítico poderia ser utilizado na sua fabricação. No entanto revestimentos protetores são necessários para bloquear a volatilidade do cromo da superfície metálica do interconector nas condições de operação das PaCOS. Neste trabalho, os revestimentos foram obtidos a partir de soluções eletrolítica contendo Co2+ e Mn2+ provenientes de catodos de baterias de íon lítio (BIL’s) exauridas. Foram feitas eletrodeposições potenciostáticas com o objetivo de se obter ligas de cobalto e manganês sobre a superfície de amostras do aço AISI 430. Dados de eficiência de carga do processo foram calculados para otimização das amostras, e a condição de pH mais ácido (pH=3) mostrou-se menos eficiente. Contudo, o filme apresentou microestrutura homogênea, menos porosa e constituída por uma camada interna de (Mn, Cr)2O3 e externa de MnCo2O4, capaz de bloquear a perda do Cr, conforme mostraram as análises de DRX, MEV e EED. Já para o pH menos ácido (pH=3,5), não foi identificada a presença do Mn na composição do depósito, e o revestimento formado de Co3O4 não se mostrou capaz de bloquear a perda de cromo por volatilidade.

Snake bite accidents are a major world public health problem particularly in the rural areas of non-developed countries...

This work reports the spectroelectrochemical and electrical behavior of electropolymerized donor-acceptor like (D-A) copolymer films, based on 3,4-ethylenedioxythiophene (EDOT) and beta-substituted electron-acceptor thiophenes. Initially, the copolymer films were deposited on indium tin oxide substrates, which spectroelectrochemistry measurements were carried out with an UV-Vis spectrophotometer. Hence, it was possible to observe the electrochromic properties of these materials, visualizing the color changing towards different potentials applied. The experiments have shown that these D-A like copolymers presented good electrochromic properties, such as optical contrast, coloration efficiency, and switching times. Additionally, films prepared on a platinum working electrode were investigated by electrochemical impedance spectroscopy, which has shown the electrical behavior of those copolymers and their potential as candidates to capacitive devices building. Therefore, the combination of electron-donor EDOT with those electron-acceptor monomers is indeed a useful strategy to tailoring and fine-tuning the physicochemical properties of polythiophenes with innovative applications.

A partir da metade do século passado, com o desenvolvimento tecnológico de novos processos de elaboração e caracterização, materiais cerâmicos inovadores, chamados cerâmicas avançadas ou de engenharia, começaram a serem desenvolvidos, aumentando consideravelmente a área de aplicações desses materiais. Enquanto as cerâmicas tradicionais são fabricadas a partir de materiais naturais, geralmente com argila, quartzo e feldspato, as cerâmicas avançadas não possuem silicatos e são elaboradas a partir de pós sintéticos de óxidos, de nitretos, de carbetos, de boretos, de carbonetos etc. Essas últimas possuem propriedades químicas, físicas e mecânicas muito superiores às cerâmicas tradicionais, como biocompatibilidade, alta dureza, altas resistências mecânica, térmica, resistência ao desgaste e à corrosão, etc.

A primary solid oxide fuel cell unit cell consists of an anode, cathode, and solid electrolyte. Each one of them can produce a low voltage, around 1 V, so that to achieve sufficient energy densities, several units need to be stacked. The electrical contact between two adjacent cells is promoted by the interconnectors, which also have the function of separating and distributing fuel and oxidant gases at the electrode. Traditionally, ceramic materials have been used as a high-temperature interconnector (~1000°C), but recent technological advances in cell fabrication and design have allowed the working temperature to be reduced to intermediate ranges, making possible to use materials with suitable properties and lower cost. As a good alternative, ferritic stainless steels have been extensively studied in the process of manufacturing interconnectors because of their low price and excellent mechanical properties compared to the previously used materials. However, at high temperatures, chromium can form gaseous oxides that migrate to the cathode and gradually reduce cell performance, a phenomenon known as chromium poisoning. As an alternative, the application of protective coatings has been widely studied because it is a simple, efficient, and low-cost method that inhibits cathode poisoning of chromium and maintains an excellent electrical resistance specific to the interconnectors. Co–Mn-based spinels have been developed as a protective layer that improves the performance of ferritic steels by inhibiting the phenomenon of poisoning and can be obtained by electrodeposition. This technique involves the deposition of a coating on a conductive surface to get coated metallic interconnectors by a simple, efficient, and low-cost method.

Serotherapy is the only approved method to treat victims of snakebites; therefore, it is very important to identify the type of venom implicated in the accident to ensure the most specific antivenom is administered to the patient. In Brazil, the majority of snakebite accidents are from snakes of Bothrops genus. In this work, we developed an immunosensor capable to recognize specifically venoms from Bothrops snakes based on the electrochemical impedance spectroscopy technique. For this, Crofer 22 APU steel was used as transducer substrate functionalized with antibothropic antibodies. The immunosensor was incubated with different concentrations of venoms from Bothrops, Crotalus, and Micrurus in order to evaluate its specificity. The formation of the antigen-antibody immunocomplex at the surface of the transducer substrate increased the leakage resistance in a concentration-dependent manner when the device was exposed to the bothropic venom, while no considerable variation of this parameter could be observed for the venoms of the heterologous genera. In addition to the observed specificity, the sensor proved reusable, since the immersion in an elution buffer permitted many regeneration and charge cycles without considerable loss of activity. The results strongly indicated that the developed immunosensor stands as a promising device to aid in snakebites diagnosis.

This review brings together publications in the form of articles, reports, theses and patents related to the use of solid oxide fuel cells in aircraft with a focus on replacing the current auxiliary units with a hybrid system. The potential advantages and main challenges of the new technology are reported, indicating some possible trends in this technology. However, even after many studies, some initial challenges remain. For example, the hybrid system did not achieve the necessary weight-efficiency-ratio, and there seems to be no consensus on the choice of the best fuel. We conclude that the most viable short-term applications appear to be unmanned units, particularly because of security issues and low technology maturity. Smaller power applications, in which the new system is responsible for peripheral services such as a power supply for air conditioning, toilets, and heating up food, are candidates to enter the market in the short or medium term. In the long term, applications for fully electric aircraft and clean fuels will certainly be the focus of larger aircraft manufacturers.

For many reasons, the material sciences have focused in studies of electroanalysis, exploring the knowledge of conductive materials that can be used as sensitive elements for composing sensors in order to specifically recognize analytes of interest [1].

A highly sensitive glucose sensor was prepared by a one-step method using 3-aminophenyl boronic acid as a unit of recognition and a screen-printed carbon electrode (SPCE) as an electrochemical transducer. Scanning Electron Microscopy confirmed the success of the functionalization of the SPCE due to the presence of clusters of boronic acid distributed on the carbon surface. In agreement with the Electrochemical Impedance Spectroscopy (EIS) tests performed before and after the functionalization, Cyclic Voltammetry results indicated that the electroactivity of the electrode decreased 37.9% owing to the presence of the poly phenylboronic acid on the electrode surface. EIS revealed that the sensor was capable to selectively detect glucose at a broad range of concentrations (limit of detection of 8.53 &times, 10&minus, 9 M), not recognizing fructose and sucrose. The device presented a stable impedimetric response when immediately prepared but suffered the influence of the storage time and some interfering species (dopamine, NaCl and animal serum). The response time at optimized conditions was estimated to be equal to 4.0 &plusmn, 0.6 s.

Electrochemical Impedance Spectroscopy EIS stands out as a powerful technique for application in electroanalytical devices Especially due to the possibility of label free performance use of miniaturized systems in situ measurements and the relative low cost impedimetric sensors have attracted particular attention in the recognition of analytes of medical environmental and industrial interests Depending on the presence or absence of redox species in the electrode or in the electrolyte the technique can be categorized as faradaic or non faradaic EIS respectively The choice of the most suitable sensing method relies mainly on the expected application Despite the non faradaic methods presents the advantages of the application in point of care devices due to the possibility of miniaturization of the electrodes and the absence of redox couple the faradaic sensors tends to be more sensitive

This work evaluates the inhibitory effect of ethanolic extract of propolis (EEP) on the corrosion of AISI 409 stainless steel (SS) in chloride media. Additions of 100, 200, and 500 μL of EEP in an aqueous sodium chloride solution were performed. The inhibitory effect on the SS was evaluated using electrochemical impedance spectroscopy (EIS) measurements up to 720 hours in immersion. EEP additions of 200 μL and 500 μL increased the polarization resistance of the SS. After 720 hours of immersion, the highest impedance was identified for the SS in solution with 500 μL of EEP. The maximum inhibition efficiency observed for addition of 500 μL of EEP in solution was 98.1 %, after 360 h of immersion. This work is licensed under a Creative Commons Attribution 4.0 International License.

Given the importance of the transducer elements in the performance of sensors for various applications, as well as the growing search for devices that are capable of providing the response in shorter time, in this work, titanium dioxide was examined as a candidate for application in an electrochemical biosensor. A TiO2 coating deposited by sol-gel method on a silicon wafer was obtained with an anatase crystalline structure, as an n-type semiconductor with donor density equal to 2.954 · 1017 cm–3. Its surface was functionalized to be tested as a biosensor to detect snake venom of the Bothrops genera, and each step of the functionalization was investigated using Electrochemical Impedance Spectroscopy (EIS) and Cyclic voltammetry. Despite being less sensitive than the reference method ELISA, the TiO2-based biosensor was also capable of detecting the analyte of interest at 20 μg mL–1, revealing an increase in its leakage resistance and phase shift after incubation in this solution. Furthermore, the total time for carrying out the biodetection with the TiO2-coated device (41.24 ± 0.05 min) was estimated to be approximately 80 % shorter than that required by the labelled standard assay, which indicates that TiO2 is a promising electrochemical transducer for biosensing applications. This work is licensed under a Creative Commons Attribution 4.0 International License.

A novel, fast, low-cost and scalable methodology to prepare stable magnetoliposomes (MGLs), without the use of organic solvents, is described. The concept of the work is based on the dual use of soy lecithin associated to a new liposome preparation methodology. Soy lecithin was used to coat the nanoparticles of magnetite (Fe3 O4 @lecithin) and for encapsulation of Fe3 O4 @lecithin (Lip-Fe3 O4 @lecithin). Liposomes with size less than 160 nm, polydispersity index of 0.25 and zeta potential of -41 mV, were prepared with the use of autoclave and sonication. The liposomal formulations containing magnetite and stigmasterol (Lip-Fe3 O4 @lecithin, Lip-Stigma and Lip-Stigma-Fe3 O4 @lecithin) were shown to be promising for the application as antibacterial. The liposomal formulation and magnetite were characterized by the following techniques: conventional and high-resolution transmission electron microscopy (TEM/HRTEM), energy-filtered transmission electron microscopy (EFTEM), proton nuclear magnetic resonance (1H NMR), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD), dynamic light scattering (DLS) and zeta potential. The Lip-Fe3 O4 @lecithin had a minimum inhibitory concentration (MIC) of 8.4 µg mL-1 in the presence of 200 Oe magnetic field against S. aureus.

Smooth and optically transparent titania (TiO2) and TiO2-reduced graphene oxide (RGO) composite films were successfully prepared here. A nanocrystalline anatase suspension was initially prepared by combining the sol-gel process and hydrothermal treatment. Graphene oxide (GO) nanosheets were prepared following a route similar to the Hummers method. Glass slides were then dip-coated using mixtures of TiO2 and GO suspensions. The concentration of GO in the prepared coatings ranged from 1 to 5 wt%. The coated samples were air-dried, and then either calcined or irradiated with UVA light. It was observed that UVA light promoted the reduction of GO to RGO, which increased both the electrical conductivity and hydrophilicity of the composites. The heat treatment of as-prepared coatings also decreased the water contact angle (WCA) with its surface, which is related to the removal of organics residues, graphene burning, and the increase in surface energy. The superhydrophilicity of the prepared samples was investigated after keeping them in air for up to 60 days, followed by UVA illumination. It was also demonstrated that a hydrophilic behavior can be induced in the samples prepared here by applying a direct current (DC) voltage, which could allow their use as smart materials in several applications.

The present work reports the synthesis of four electron-acceptor beta-substituted thiophenes that were studied as monomers for electrochemical polymerization with 3,4-ethylenedioxythiophene (EDOT), an electron-donating monomer, aiming the combination of electron-acceptor and donor monomer thiophene to a simpler and convenient build up of novel donor–acceptor copolymeric materials via electrochemical polymerization. Four novel copolymers poly(EDOT-co-3-thiophene phenylacetate), (PEDOT-co-PPhTAc-2a), poly(EDOT-co-3-thiophene(4-nitrophenyl)acetate) (PEDOT-co-PPhTAc-2b), poly(EDOT-co-3-thiophenephenylcarboxylate) (PEDOT-co-PPhTCb), and poly(EDOT-co-3-(phenoxymethyl)thiophene) (PEDOT-co-PPhOMT) were electrochemically polymerized. The monomers were characterized by spectrometric techniques (FTIR, 1H NMR, and 13C NMR), and the copolymers were identified by electrochemical analyses and FT-IR. Although the corresponding homopolymers could not be obtained, in the presence of EDOT, the copolymers were formed in a quasi-reversible electrochemical kinetics. The infrared spectra of the copolymers as well the electrochemical profile corroborates their obtaining. The mass variation during the electrosynthesis was analyzed using a quartz crystal microbalance. The film’s morphologies were investigated by SEM. Interestingly, the combination of electron-rich monomer thiophene (EDOT) and these electron-deficient carboxy-substituted thiophenes might be a convenient building block couple to increase the performance control of physic-chemical properties of mixed polythiophenes with innovative applications and they also showed a possible applicability as charge storage device.

In this work, anode-supported solid oxide fuel cells (SOFC) were tested with a yttria-stabilized zirconia (YSZ) (8 mol% Y2O3-ZrO2)/gadolinium-doped ceria (GDC) (Ce0.9Gd 0.1O1.95) bilayer electrolyte and two lanthanum strontium cobalt ferrite (LSCF) composition as functional cathode layer: La0.6Sr0.4Co0.8Fe0.2O3-δ (LSCF 1) and La0.60Sr0.40Co0.2Fe0.8O3-δ (LSCF 2). The functional cathode layers were made of 50 % (w/w) LSCF and 50 % (w/w) GDC. Microstructural characterization was performed by scanning electron microscopy and X-ray diffraction. Electrochemical impedance spectroscopy (EIS) and power measurements were performed under oxygen and hydrogen atmospheres. The microscopy studies showed that the LSCF 2 functional layer is more uniform and adherent to the electrolyte and the cathode collector than the LSCF 1 functional layer, which has cracks, chips, and lower adhesion. The use of the LSCF 2 layer allowed an approximately 25-fold reduction in ohmic resistance (0.06 Ω cm−2) compared with the LSCF 1 layer (1.5 Ω cm−2). The power measurements showed a considerable increase in the power cell using LSCF 2 (approximately 420 mW cm−2) compared with the power cell using LSCF 1 (approximately 180 mW cm−2).

Electrochemical and surface analyses were carried out to study the leaching of chalcopyrite in acid media, aiming to increase copper extraction from low-grade chalcopyrite ores. Unpublished results include the use of electrochemical impedance spectroscopy (EIS) to characterize the dissolution resistance of chalcopyrite surfaces in 0.1 mol·L − 1 of hydrochloric, nitric or sulfuric acids. Potentiodynamic polarization, atomic absorption spectrometry and EIS analysis showed that hydrochloric acid solutions are more efficient leaching agents than nitric and sulfuric acids. The impedance results suggested that the chalcopyrite dissolution is a diffusion-controlled process in hydrochloric and sulfuric acids. The use of Raman spectroscopy and scanning electron microscopy with energy dispersive spectrometers (SEM/EDS) allowed the partial identification of lead and bismuth sulfides as impurities. Two products were identified on the surface of chalcopyrite after anodic polarization, i.e., sulfur in the sulfuric acid only and covellite in all three acids.

This article aims to present a new alternative to waste management of spent Li-ion batteries from cell phones. In this sense, the proposed is recycling the cobalt from Li-ion cathode by electrodeposition and apply it as corrosion protector of AISI 430 stainless steel. Thus, two greatest environmental problems can be solved, producing a low-cost and high-corrosion-resistant stainless steel. The cobalt electrodeposition bath came from acid dissolution of spent Li-ion cathode with chemical formula LiCoO2. The charge efficiency for cobalt electrodeposition in −1.0 V and pH = 3 reaches 95 %. A protective layer of Co3O4 was successfully obtained by treatment of AISI 430 stainless steel with cobalt electrodeposited at 800 °C for 200 h in air atmosphere. The corrosion current of AISI 430 stainless steel in artificial seawater was reduced from 30 to 0.76 μA cm−2. The treatment proposed produces a AISI 430 stainless steel with double of corrosion resistance and half of cost if compared with AISI 304 stainless steel.

The anticorrosion performance of commercial extract of ethanolic propolis (EP)-coated mild steel samples immersed in a 3.5% w/v NaCl in neutral and near neutral media was evaluated by classical electrochemical and electrochemical probe beam deflection techniques. The functional groups and major components of the extract were identified by Fourier transform infrared spectroscopy and high-performance liquid chromatography, respectively. The extract and the major constituent identified in the extract, 3,5-diprenyl-4-hydroxycinnamic acid (DHCA), are poorly hydro-soluble in a neutral medium. The bare and coated carbon steel surfaces were characterized by scanning electron microscopy and atomic force microscopy before and after a saline immersion. The electrochemical response of the coated electrodes was compared with bare mild steel electrodes and all qualitative and quantitative data obtained supported the hypothesis that EP is a potential mild steel corrosion inhibitor. Although several flavonoids are known to have remarkable antioxidant properties and be effective metal corrosion inhibitors, this work is pioneering in its evaluation of the inhibitory capacity of a natural product whose main constituent is DHCA.

This study discusses the solid oxide fuel cell (SOFC) technology paths in the United States and Japan under the national innovation system (NIS) framework using the available literature and a patent landscape. By examining technology trajectories, it is possible to identify and justify the patterns of key players and institutions from the NISs of the two countries that shaped the development of these technologies. These patterns are especially relevant to the analysis of the role of institutional arrangements in policymaking. This study presents the concept of a NIS and explores the main aspects of the Japanese and U.S. NISs regarding the SOFC technology path. This study analyzes historical patent evolution, patent applicants and their industrial sectors, international patent classifications (IPCs) and international patent activity. Moreover, this study highlights the correlations of the SOFC manufacturing and operation with patent data. This study examines the role of NISs in SOFC technology shaping from two main aspects: through independent historical events that motivated the establishment of institutional arrangements from which SOFCs have benefited and through shaping policies and efforts that are intended to promote the development of SOFC and related technologies. The results of this study demonstrate differences in terms of the sectors that are involved in the SOFC patenting activity, the IPCs of the filed patents and the international patent activity, which support the role of NISs in technology shaping.

The original version of the article was published with errors in the Eq. 3, 4, 5, 6 and 7. These are corrected by publishing this correction article. The correct equations are given below.

We report the synthesis of a CNT-TEPA@PEPy hybrid material by the copolymerization of EDOT and Py analogs units covalently bonded to TEPA modified carbon nanotubes (CNTs). The chemical structure and morphology of the hybrid were compared to those of the unmodified CNTs using FTIR, Raman and XPS spectroscopies. The hybrid was applied as the electrode active material in symmetric supercapacitors (SCs) which were evaluated in aqueous and organic (acetonitrile) electrolytes to study the versatility of the as-synthesized CNT-TEPA@PEPy. The capacitances values of the cells obtained from the hybrid-based SCs are 56% and 115% higher than those of the cells prepared with the unmodified CNT in organic and aqueous electrolytes, respectively. The full cells assembled with CNT-TEPA@PEPy exhibited excellent cyclability with 81.3% and 77.5% of capacitance retention after 5000 cycles in aqueous and organic media, respectively. The device properties indicate the feasibility of the applied synthetic approach, showing that the prepared hybrid is a promising material for use in highly cyclable supercapacitors.

We present the synthesis of nanohybrids based on carbon nanotube with EDOT/Py derivatives copolymers, P(EDOT-co-MPy) and P(EDOT-co-PyMP). These hybrids were prepared with functionalized MWCNT via in-situ polymerization for aqueous supercapacitor applications. The chemical structure and morphology of the hybrids were compared with those of neat copolymers and MWCNTs using FTIR, Raman and XPS spectroscopies. The results provided evidence of a covalent attachment between the copolymer and nanotubes. The electrodes were used in symmetric supercapacitor cell configuration and their performance was evaluated using cyclic voltammetry (CV), galvanostatic charge/discharge tests and electrochemical impedance spectroscopy (EIS). The hybrids presented an improvement in the capacitance values compared to a pure capacitive system (MWCNT) and the neat copolymers. The rate capability of the cells was also improved as a result of an enhancement in charge transfer in the nanohybrids. The devices showed high performance with excellent cycling stability, compared to the poor cyclability of the conjugated polymers, even after 20,000 cycles.

The recycling of exhausted lithium-ion batteries from mobile phones originate five solutions with different Co and Mn proportions that were used as electrolytic solutions to obtain Mn-Co spinel coatings on the surface of AISI430 stainless steel. The coatings are intended to contain chromium volatility in the working conditions of Solid Oxide Fuel Cells (SOFC) metallic interconnectors. Potentiostatic electrodeposition was the technique used to obtain Mn-Co coatings from low concentration electrolytes at pH = 3.0 and potential applied &minus, 1.3 V. Charge efficiency data were used for sample optimization. Three optimized samples were subjected to oxidation heat treatment at 800 &deg, C for 300 h and then characterized by XRD, SEM and EDS. The results showed that the addition of manganese ions instead of cobalt ions in the electrolytic bath produces more stable and well-distributed deposits as the ratio of the two ions becomes equal in the electrolytic bath. Thin, homogeneous and stable spinel coatings (Mn, Co)3O4 2.8 &mu, m and 3.9 &mu, m thick were able to block chromium volatility when exposed to SOFC operating temperature.

Materials based on a mixture of poly(vinylidene fluoride) (PVDF), poly(2-hydroxyethyl methacrylate) (PHEMA) and LiClO4 were produced to evaluate their ionic behavior and morphological structure to determine if they can be used as an electrolyte in electrical devices. FTIR chemical analysis results indicated the presence of interactions between PVDF, PHEMA and LiClO4. MDSC results showed that the transition temperatures of the polymers shifted to higher temperatures for systems containing high concentrations of each polymer. SEM images indicated that there was some miscibility between the polymers especially for the 25 and 75 wt. % compositions. In terms of the electrical performance, the ionic conductivity level of the electrolyte could be controlled by changing the composition of the system.

This paper describes briefly the use of Ni-YSZ (yttrium oxide doped with 8 % in mol of zirconium oxide) for methanol oxidation in 1.0 mol L−1 KOH solution. The Ni-YSZ has a great performance for methanol oxidation reaching a current density around 160 mA cm−2. This value is at least four times greater than in platinum electrode. The high performance of Ni-YSZ compared with Pt electrode can also be viewed in measures electrochemical impedance spectroscopy. The Ni-YSZ shows the charge transfer resistance around 1.80 Ohm cm2. Thus, in our material, the effect of NiO(OH) barrier is drastically reduced. The chronoamperograms for methanol oxidation at potential equal to 1.0 V shows that the charge density for Ni-YSZ electrode is about four times larger than in Pt electrode.