Articles de revues : « Organometallic Fuel Cells »

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Ramirez-Meneses, E., M. A. Dominguez-Crespo et A. M. Torres-Huerta. « Stabilized Metal Nanoparticles from Organometallic Precursors for Low Temperature Fuel Cells ». Recent Patents on Nanotechnology 7, n^o 1 (1 janvier 2013) : 13–25. http://dx.doi.org/10.2174/187221013804484881.

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Ramirez-Meneses, E., M. A. Domínguez-Crespo et A. M. Torres-Huerta. « Stabilized Metal Nanoparticles from Organometallic Precursors for Low Temperature Fuel Cells ». Recent Patents on Nanotechnology 7, n^o 1 (1 novembre 2012) : 13–25. http://dx.doi.org/10.2174/1872210511307010013.

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Bellini, Marco, Manuela Bevilacqua, Jonathan Filippi, Alessandro Lavacchi, Andrea Marchionni, Hamish A. Miller, Werner Oberhauser, Francesco Vizza, Samuel P. Annen et H. Grützmacher. « Energy and Chemicals from the Selective Electrooxidation of Renewable Diols by Organometallic Fuel Cells ». ChemSusChem 7, n^o 9 (31 juillet 2014) : 2432–35. http://dx.doi.org/10.1002/cssc.201402316.

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Bellini, Marco, Manuela Bevilacqua, Jonathan Filippi, Alessandro Lavacchi, Andrea Marchionni, Hamish A. Miller, Werner Oberhauser, Francesco Vizza, Samuel P. Annen et H. Grützmacher. « Energy and Chemicals from the Selective Electrooxidation of Renewable Diols by Organometallic Fuel Cells ». ChemSusChem 7, n^o 9 (19 août 2014) : 2369. http://dx.doi.org/10.1002/cssc.201402750.

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Bellini, Marco, Manuela Bevilacqua, Jonathan Filippi, Alessandro Lavacchi, Andrea Marchionni, Hamish A. Miller, Werner Oberhauser, Francesco Vizza, Samuel P. Annen et H. Grützmacher. « Cover Picture : Energy and Chemicals from the Selective Electrooxidation of Renewable Diols by Organometallic Fuel Cells (ChemSusChem 9/2014) ». ChemSusChem 7, n^o 9 (19 août 2014) : 2367. http://dx.doi.org/10.1002/cssc.201402749.

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Armstrong, Fraser A., et Simon P. J. Albracht. « [NiFe]-hydrogenases : spectroscopic and electrochemical definition of reactions and intermediates ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 363, n^o 1829 (15 avril 2005) : 937–54. http://dx.doi.org/10.1098/rsta.2004.1528.

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Production and usage of di-hydrogen, H 2 , in micro-organisms is catalysed by highly active, ‘ancient’ metalloenzymes known as hydrogenases. Based on the number and identity of metal atoms in their active sites, hydrogenases fall into three main classes, [NiFe]-, [FeFe]- and [Fe]-. All contain the unusual ligand CO (and in most cases CN − as well) making them intriguing examples of ‘organometallic’ cofactors. These ligands render the active sites superbly ‘visible’ using infrared spectroscopy, which complements the use of electron paramagnetic resonance spectroscopy in studying mechanisms and identifying intermediates. Hydrogenases are becoming a focus of attention for research into future energy technologies, not only H 2 production but also H 2 oxidation in fuel cells. Hydrogenases immobilized on electrodes exhibit high electrocatalytic activity, providing not only an important new technique for their investigation, but also a basis for novel fuel cells either using the enzyme itself, or inspired synthetic catalysts. Favourable comparisons have been made with platinum electrocatalysts, an advantage of enzymes being their specificity for H 2 and tolerance of CO. A challenge for exploiting hydrogenases is their sensitivity to O 2 , but some organisms are known to produce enzymes that overcome this problem by subtle alterations of the active site and gas access channels.

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Fu, Bo, Wayne Huebner, Mladen F. Trubelja et Vladimir S. Stubican. « Synthesis and properties of strontium-doped yttrium manganite ». Journal of Materials Research 9, n^o 10 (octobre 1994) : 2645–53. http://dx.doi.org/10.1557/jmr.1994.2645.

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The system Y1−xSrxMnO3 (x = 0.000, 0.005, 0.010, 0.050, and 0.100) was studied as a potential cathode material for solid oxide fuel cells. Powders were prepared using an organometallic precursor; however, achieving homogeneous compositions was complicated due to the presence of intermediate, metastable phases. The desired hexagonal Y1−xSrxMnO3 phase formed from the precursor at 800 °C, while small amounts of a metastable orthorhombic (Y,Sr)MnO3 phase formed in the temperature range between 850°and 960 °C, and another orthorhombic YMn2O5 phase between 840°and 1200 °C. The metastable (Y, Sr)MnO3 phase readily transformed into the stable hexagonal phase at about 960 °C. The other metastable intermediate phase, YMn2O5, was formed as a decomposition product of a portion of the major hexagonal YMnO3 at 840 °C, and subsequently reacted with Y2O3 back to the hexagonal YMnO3 at 1200 °C. For the studied compositions, densities higher than 95% theoretical could be obtained by sintering in air at temperatures above 1400 °C for 2 h. The investigated system was comparable in electrical conductivity with the current cathode material La1−xSrxMnO3, and had an average apparent thermal expansion coefficient between 5 and 7 ppm/°C in the temperature range between 200°and 1000 °C. Unfortunately microcracking was observed in all sintered specimens, possibly caused by a high-temperature phase transition between the hexagonal and cubic polymorphs of Y1−xSrxMnO3. The microcracking presents a major obstacle to the use of this material as a cathode in solid oxide fuel cells.

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Monopoli, Antonio, Michele Casiello, Pietro Cotugno, Antonella Milella, Fabio Palumbo, Francesco Fracassi et Angelo Nacci. « Synthesis of Tailored Perfluoro Unsaturated Monomers for Potential Applications in Proton Exchange Membrane Preparation ». Molecules 26, n^o 18 (15 septembre 2021) : 5592. http://dx.doi.org/10.3390/molecules26185592.

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The aim of the present work is the synthesis and characterization of new perfluorinated monomers bearing, similarly to Nafion®, acidic groups for proton transport for potential and future applications in proton exchange membrane (PEM) fuel cells. To this end, we focused our attention on the synthesis of various molecules with (i) sufficient volatility to be used in vacuum polymerization techniques (e.g., PECVD)), (ii) sulfonic, phosphonic, or carboxylic acid functionalities for proton transport capacity of the resulting membrane, (iii) both aliphatic and aromatic perfluorinated tags to diversify the membrane polarity with respect to Nafion®, and (iv) a double bond to facilitate the polymerization under vacuum giving a preferential way for the chain growth of the polymer. A retrosynthetic approach persuaded us to attempt three main synthetic strategies: (a) organometallic Heck-type cross-coupling, (b) nucleophilic displacement, and (c) Wittig–Horner reaction (carbanion approach). Preliminary results on the plasma deposition of a polymeric film are also presented. The variation of plasma conditions allowed us to point out that the film prepared in the mildest settings (20 W) shows the maximum monomer retention in its structure. In this condition, plasma polymerization likely occurs mainly by rupture of the π bond in the monomer molecule.

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Matloobi, Roya, Rasol Abdullah Mirzaie et Azam Anaraki Firooz. « Achievement of a novel organometallic electrocatalyst based on nickel and poly para-aminophenol with excellent oxygen reduction reaction activity : Promoting the commercialization of low temperature fuel cells ». Sustainable Energy Technologies and Assessments 51 (juin 2022) : 101988. http://dx.doi.org/10.1016/j.seta.2022.101988.

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Hoseini, S. Jafar, Mehrangiz Bahrami et Modarres Dehghani. « Formation of snowman-like Pt/Pd thin film and Pt/Pd/reduced-graphene oxide thin film at liquid–liquid interface by use of organometallic complexes, suitable for methanol fuel cells ». RSC Advances 4, n^o 27 (2014) : 13796. http://dx.doi.org/10.1039/c4ra01625d.

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Dudek, Magdalena, Bartłomiej Lis, Alicja Rapacz-Kmita, Marcin Gajek, Andrzej Raźniak et Ewa Drożdż. « Some observations on the synthesis and electrolytic properties of (Ba1-xCax) (M0.9Y0.1)O3, M = Ce, Zr-based samples modified with calcium ». Materials Science-Poland 34, n^o 1 (1 mars 2016) : 101–14. http://dx.doi.org/10.1515/msp-2016-0022.

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AbstractIn this paper, the impact of partial substitution of calcium for barium in (Ba1-xCax) (M0.9Y0.1) O3, M = Ce, Zr on physicochemical properties of the powders and sintered samples was investigated. The powders, with various contents of calcium (x = 0, 0.02, 0.05, 0.1), were prepared by means of thermal decomposition of organometallic precursors containing EDTA. All of the BaCeO3-based powders synthesised at 1100 °C were monophasic with a rhombohedral structure, however, completely cubic BaZrO3-based solid solutions were obtained at 1200 °C. A study of the sinterability of BaZr0.9Y0.1O3 and BaCe0.9Y0.1O3-based pellets was performed under non-isothermal conditions within a temperature range of 25 to 1200 °C. The partial substitution of barium for calcium in the (Ba1-xCax) (M0.9Y0.1) O3, M = Ce, Zr solid solution improved the sinterability of the samples in comparison to the initial BaCe0.9Y0.1O3 or BaZr0.9Y0.1O3. The relative density of calcium-modified BaCe0.9Y0.1O3-based samples reached approximately 95 to 97 % after sintering at 1500 °C for 2 h in air. The same level of relative density was achieved after sintering calcium-modified BaZr0.9Y0.1O3 at 1600 °C for 2 h. Analysis of the electrical conductivity from both series of investigated materials showed that the highest ionic conductivity, in air and wet 5 % H2 in Ar, was attained for the compositions of x = 0.02 to 0.05 (Ba1-xCax)(M0.9Y0.1)O3, M = Zr, Ce. The oxygen reduction reaction on the interface Pt│BaM0.9Y0.1O3, M = Ce, Zr was investigated using Pt microelectrodes. Selected samples of (Ba1-xCax) (M0.9Y0.1)O3, M = Zr, Ce were tested as ceramic electrolytes in hydrogen-oxygen solid oxide fuel cells operating at temperatures of 700 to 850 °C.

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Kulesza, Pawel J., Ewelina Seta-Wiaderek, Anna Wadas, Iwona A. Rutkowska et Weronika Lotowska. « (Invited) Bacterial Biofilms As Active Components of Electrocatalytic and Photoelectrochemical Systems for Reduction of Carbon Dioxide ». ECS Meeting Abstracts MA2022-01, n^o 36 (7 juillet 2022) : 1574. http://dx.doi.org/10.1149/ma2022-01361574mtgabs.

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Most of the bacterial species form biofilms, in which microorganisms are attached to a surface and they are held together by extracellular polymeric substances that they produce. They tend to grow almost everywhere both on living or non-living surfaces. Biofilms are able to propagate charge within their structures and to transfer effectively electrons at interfaces, as well as they could exhibit electrocatalytic properties (e.g. in Microbial Fuels Cells). The application of microbes provides better flexibility: experiments with fuel cells can be operated at normal conditions (temperatures and pressures). Wide variety of microbial metabolic pathways gives the possibility to use aggregates of bacteria in diverse processes. Proposed electrochemical studies using bacterial biofilms (in the form of thin coatings on the glassy carbon electrodes) can be considered as an attempt to find efficient methods of using the energy produced by microorganisms and converting it to electricity. The ultimate goal of the present research has been to determine whether it is possible under laboratory conditions to perform electrocatalytic processes using the hybrid (composite) layers composed of aggregates of bacteria in pristine or modified forms. A biofilm formed by a strain of Yersinia enterocolitica (Y. enterocolitica) is characterized by a high physicochemical stability over a wide pH range (4-10) and temperatures (0-40°C).The subject of interest is a fairly complex reaction, electroreduction of carbon dioxide. There has been growing interest in the search of electrocatalytic anf photoelectrochemical systems capable of efficient conversion of carbon dioxide into fuels and utility chemicals. Our previously performed studies have clearly shown that the Y. enterocolitica biofilm itself has no activity with respect to reduction of CO2, however it acts as a good matrix for the catalytic (e.g. noble metal or metaloorganic) centers [1,2], because it affects the reaction mechanism and appears to decrease overpotential of the electroreduction processes. The conducted research shows that the composite materials containing bacterial biofilms can be successfully used to construct systems that have an electrocatalytic reactivity in the reduction of carbon dioxide. In particular, the influence of the biological matrix on the catalytic activity of different transition metal nanoparticles (Pd, Pt, Ru, PtRu) in the carbon dioxide conversion process will be compared. Here, the successful system based on platinum nanoparticles deposited on the biological carrier, Y. enterocolitica biofilm, supported onto conductive polymer (polyaniline) and utilizing multi-walled carbon nanotubes should be mentioned. We will also address the possibility of dispersing the organometallic ruthenium (II) complex in the biological layer (biofilm). Indeed, the ruthenium (II) complex has been immobilized in the biofilm matrix by successive modification of the liquid medium (Luria-Bertani medium) for culturing bacteria with a solution of the complex compound. In addition, the biological matrix was used (along with the ruthenium (II) complex molecules dispersed in its layer) as a protective coating, stabilizing the unstable p-type semiconductor - copper (I) oxide. The proposed hybrid co-catalytic system showed activity during the photoelectrochemical reduction of carbon dioxide and stability under semi-neutral experimental conditions. Finally, we are going to address the design of the above-mentioned catalytically active systems emphasizing the need to control the structure of the studied hybrid materials (in addition to their stability). Among important issues is the viability of bacteria in the biological membrane as well as elucidation of the role of the bacterial biofilm during the carbon dioxide reduction. [1] Seta E., Lotowska W., Rutkowska I.A., Wadas A., Raczkowska A., Nieckarz. M., Brzostek K., Kulesza P.J., Australian Journal of Chemistry 69 (2016) 411-418. [2] Lotowska W., Rutkowska I.A., Seta E., Szaniawska E., Wadas A., Raczkowska A., Brzostek K., Kulesza P.J., Electrochimica Acta 213 (2016) 314-323.

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Balčiūnas, Dreižė, Grubliauskaitė, Urnikytė, Šimoliūnas, Bukelskienė, Valius, Baldock, Hardy et Baltriukienė. « Biocompatibility Investigation of Hybrid Organometallic Polymers for Sub-Micron 3D Printing via Laser Two-Photon Polymerisation ». Materials 12, n^o 23 (27 novembre 2019) : 3932. http://dx.doi.org/10.3390/ma12233932.

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Hybrid organometallic polymers are a class of functional materials which can be used to produce structures with sub-micron features via laser two-photon polymerisation. Previous studies demonstrated the relative biocompatibility of Al and Zr containing hybrid organometallic polymers in vitro. However, a deeper understanding of their effects on intracellular processes is needed if a tissue engineering strategy based on these materials is to be envisioned. Herein, primary rat myogenic cells were cultured on spin-coated Al and Zr containing polymer surfaces to investigate how each material affects the viability, adhesion strength, adhesion-associated protein expression, rate of cellular metabolism and collagen secretion. We found that the investigated surfaces supported cellular growth to full confluency. A subsequent MTT assay showed that glass and Zr surfaces led to higher rates of metabolism than did the Al surfaces. A viability assay revealed that all surfaces supported comparable levels of cell viability. Cellular adhesion strength assessment showed an insignificantly stronger relative adhesion after 4 h of culture than after 24 h. The largest amount of collagen was secreted by cells grown on the Al-containing surface. In conclusion, the materials were found to be biocompatible in vitro and have potential for bioengineering applications.

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Shui, Jianglan, Chen Chen, Lauren Grabstanowicz, Dan Zhao et Di-Jia Liu. « Highly efficient nonprecious metal catalyst prepared with metal–organic framework in a continuous carbon nanofibrous network ». Proceedings of the National Academy of Sciences 112, n^o 34 (10 août 2015) : 10629–34. http://dx.doi.org/10.1073/pnas.1507159112.

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Fuel cell vehicles, the only all-electric technology with a demonstrated >300 miles per fill travel range, use Pt as the electrode catalyst. The high price of Pt creates a major cost barrier for large-scale implementation of polymer electrolyte membrane fuel cells. Nonprecious metal catalysts (NPMCs) represent attractive low-cost alternatives. However, a significantly lower turnover frequency at the individual catalytic site renders the traditional carbon-supported NPMCs inadequate in reaching the desired performance afforded by Pt. Unconventional catalyst design aiming at maximizing the active site density at much improved mass and charge transports is essential for the next-generation NPMC. We report here a method of preparing highly efficient, nanofibrous NPMC for cathodic oxygen reduction reaction by electrospinning a polymer solution containing ferrous organometallics and zeolitic imidazolate framework followed by thermal activation. The catalyst offers a carbon nanonetwork architecture made of microporous nanofibers decorated by uniformly distributed high-density active sites. In a single-cell test, the membrane electrode containing such a catalyst delivered unprecedented volumetric activities of 3.3 A⋅cm−3 at 0.9 V or 450 A⋅cm−3 extrapolated at 0.8 V, representing the highest reported value in the literature. Improved fuel cell durability was also observed.

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Zhang, Jingwen, Anaïs Pitto-Barry, Lijun Shang et Nicolas P. E. Barry. « Anti-inflammatory activity of electron-deficient organometallics ». Royal Society Open Science 4, n^o 11 (novembre 2017) : 170786. http://dx.doi.org/10.1098/rsos.170786.

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We report an evaluation of the cytotoxicity of a series of electron-deficient (16-electron) half-sandwich precious metal complexes of ruthenium, osmium and iridium ([Os/Ru( η 6 - p -cymene)(1,2-dicarba- closo -dodecarborane-1,2-dithiolato)] ( 1/2 ), [Ir( η 5 -pentamethylcyclopentadiene)(1,2-dicarba- closo -dodecarborane-1,2-dithiolato)] ( 3 ), [Os/Ru( η 6 - p -cymene)(benzene-1,2-dithiolato)] ( 4/5 ) and [Ir( η 5 -pentamethylcyclopentadiene)(benzene-1,2-dithiolato)] ( 6 )) towards RAW 264.7 murine macrophages and MRC-5 fibroblast cells. Complexes 3 and 6 were found to be non-cytotoxic. The anti-inflammatory activity of 1–6 was evaluated in both cell lines after nitric oxide (NO) production and inflammation response induced by bacterial endotoxin lipopolysaccharide (LPS) as the stimulus. All metal complexes were shown to exhibit dose-dependent inhibitory effects on LPS-induced NO production on both cell lines. Remarkably, the two iridium complexes 3 and 6 trigger a full anti-inflammatory response against LPS-induced NO production, which opens up new avenues for the development of non-cytotoxic anti-inflammatory drug candidates with distinct structures and solution chemistry from that of organic drugs, and as such with potential novel mechanisms of action.

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Đurović, Momir, et Siniša Đurović. « RENEWABLES AND NEW MATERIALS ». Contemporary Materials 8, n^o 1 (10 janvier 2017). http://dx.doi.org/10.7251/comen1701021d.

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Different types of new materials and their application in renewable energy sources are discussed. The new materials in Solar cells like perovskite, ferroelectric, organometallic, ceramic, as well as different technologies such as tandem, multi junction or concentrated are presented. Fuel cells in particular SOFC (Solid Oxide Fuel Cell) as well as new tendencies in membranes and electrodes have been discussed. The trends to use fiber and composites for the blades in wind power, concrete towers, methods for sealing and protecting from corrosion are given, too. Some aspects of new batteries like flow batteries, zinc-air and aluminum-ion batteries, tidal and wave energy are reported.

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Chyan, Oliver, Jin-Jian Chen, Min Liu, Michael G. Richmond et Kaiyuan Yang. « High Surface Area Electrode Materials by Derect Metallization of Porous Substrates ». MRS Proceedings 393 (1995). http://dx.doi.org/10.1557/proc-393-265.

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ABSTRACTRecent advances in high surface area (HSA) electrode materials have played an important role in the development of high-performance batteries and fuel cells. HSA electrodes can significantly increase the power-density of batteries and fuel cells by enhancing the heterogeneous electrochemical reaction rate and concurrently reducing battery and fuel cell size and weight. The compactness of HSA electrodes can also reduce the ohmic potential drop, which has the clear advantage of reducing power losses. This paper reports results on utilizing direct metallization of porous substrates to prepare new HSA electrode materials. Specifically, Nickel HSA electrode materials, relevant to the Ni-Cd and metal-hydride rechargeable batteries, were prepared on porous carbon substrates by direct thermolysis of organometallic precursors and/or electroless Ni plating. SEM and XPS characterization results indicate a Ni metallic film was conformally coated over the porous carbon skeleton. The real electroactive areas were determined electrochemically in NaOH solution and results will be discussed in correlation with the metallization conditions.

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Roquero, Pedro, Luis Carlos Ordóñez, Omar Herrera, Orlando Ugalde et Jorge Ramírez. « Synthesis and Characterization of Carbon-Supported Platinum-Molybdenum and Platinum-Tungsten Catalysts for Methanol Oxidation in Direct Alcohol Fuel Cells ». International Journal of Chemical Reactor Engineering 5, n^o 1 (15 novembre 2007). http://dx.doi.org/10.2202/1542-6580.1491.

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A series of carbon-supported bimetallic catalysts with different metallic loadings was synthesized, using platinum as the principal active phase and molybdenum or tungsten as promoting phases. The materials were prepared by organometallic precursor thermolysis and characterized by direct current electrochemical methods, transmission electron microscopy, scanning electron microscopy and x-ray diffraction. Electrodes were elaborated with each catalyst and their electrochemical performances were studied by cyclic voltammetry. These results show an increased activity of the catalysts with small amounts of Mo or W, towards oxidation of methanol with respect to the catalyst containing only platinum. XRD results reveal the presence of molybdenum or tungsten bronzes (HxMoO3, HxWO3) that are responsible for the increase in activity. It is believed that the bronzes participate in a spillover effect by promoting the removal of protons from the platinum surface. It was found that the presence of molybdenum in this type of catalyst prevents the platinum phase from sintering during the thermal treatment and allows them to keep platinum particles with mean sizes between 2 and 8 nm. The proposed catalysts are adequate for methanol oxidation in liquid-fuel alcohol fuel cell systems, since it was found that oxidation potentials are lower than those observed with platinum catalysts.

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