260,544 research outputs found

    Electro-oxidation of Ethanol on Carbon Supported PtSn and PtSnNi Catalysts

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    Even though platinum is known as an active electro-catalyst for ethanol oxidation at low temperatures (< 100 oC), choosing the electrode material for ethanol electro-oxidation is a crucial issue. It is due to its property which easily poisoned by a strong adsorbed species such as CO. PtSn-based electro-catalysts have been identified as better catalysts for ethanol electro-oxidation. The third material is supposed to improved binary catalysts performance. This work presents a study of the ethanol electro-oxidation on carbon supported Pt-Sn and Pt-Sn-Ni catalysts. These catalysts were prepared by alcohol reduction. Nano-particles with diameters between 2.5-5.0 nm were obtained. The peak of (220) crystalline face centred cubic (fcc) Pt phase for PtSn and PtSnNi alloys was repositioned due to the presence of Sn and/or Ni in the alloy. Furthermore, the modification of Pt with Sn and SnNi improved ethanol and CO electro-oxidation. Copyright © 2016 BCREC GROUP. All rights reserved Received: 10th November 2015; Revised: 1st February 2016; Accepted: 1st February 2016 How to Cite: Hidayati, N., Scott, K. (2016). Electro-oxidation of Ethanol on Carbon Supported PtSn and PtSnNi Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1): 10-20. (doi:10.9767/bcrec.11.1.394.10-20) Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.394.10-2

    Electro-precipitation of magnetite nanoparticles: an electrochemical study

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    Nanoparticles of magnetites (Fe3O4) are synthesized with a new process based on electro-precipitation in ethanol medium. A mechanism pathway is proposed consisting of a Fe(OH)3 precipitation followed by the reduction of iron hydroxide to magnetite in the presence of hydroxyl ions which are enerated at the cathode

    Microcracking in piezoelectric materials by the Boundary Element Method

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    A 3D boundary element model for piezoelectric polycrystalline micro-cracking is discussed in this contribution. The model is based on the boundary integral representation of the electro-mechanical behavior of individual grains and on the use of a generalized cohesive formulation for inter-granular micro-cracking. The boundary integral formulation allows to address the electro-mechanical boundary value problem in terms of generalized grain boundary and inter-granular displacements and tractions only, which implies the natural inclusion of the cohesive laws in the formulation, the simplification of the analysis pre-processing stage, and the reduction of the number of degrees of freedom of the overall analysis with respect to other popular numerical methods

    Electrolysis of Converter Matte in Molten CaCl2-NaCl

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    The electrolytic production of nickel-copper alloy by electrochemical reduction of converter matte in molten salt has been investigated. The sintered solid porous pellets of Ni3S2, Cu2S and converter matte were electrolyzed at a voltage of 3.0 V in molten CaCl2-NaCl under the protection of argon gas at 700?, respectively. The electro-reduction processes were investigated and the products were characterized. The results show that the molten salt electro-reduction process can be used to produce nickel, copper and nickel-copper alloy directly from Ni3S2, Cu2S and converter matte precursors in molten CaCl2-NaCl, respectively. CaS would be formed as the intermediate compound during the electro-reduction process, and then the formed CaS can be gradually decomposed and removed with the increase of the electrolysis time. The experimental results show that the molten salt electro-reduction process has the potential to be used for the reduction of sulfide minerals in molten CaCl2-NaClpublishersversionPeer reviewe

    Massless particles, electromagnetism, and Rieffel induction

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    The connection between space-time covariant representations (obtained by inducing from the Lorentz group) and irreducible unitary representations (induced from Wigner's little group) of the Poincar\'{e} group is re-examined in the massless case. In the situation relevant to physics, it is found that these are related by Marsden-Weinstein reduction with respect to a gauge group. An analogous phenomenon is observed for classical massless relativistic particles. This symplectic reduction procedure can be (`second') quantized using a generalization of the Rieffel induction technique in operator algebra theory, which is carried through in detail for electro- magnetism. Starting from the so-called Fermi representation of the field algebra generated by the free abelian gauge field, we construct a new (`rigged') sesquilinear form on the representation space, which is positive semi-definite, and given in terms of a Gaussian weak distribution (promeasure) on the gauge group (taken to be a Hilbert Lie group). This eventually constructs the algebra of observables of quantum electro- magnetism (directly in its vacuum representation) as a representation of the so-called algebra of weak observables induced by the trivial representation of the gauge group.Comment: LaTeX, 52 page

    Bilirubin oxidase from myrothecium verrucaria physically absorbed on graphite electrodes. Insights into the alternative resting from and the sources of activity loss

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    The oxygen reduction reaction is one of the most important chemical processes in energy converting systems and living organisms. Mediator-less, direct electro-catalytic reduction of oxygen to water was achieved on spectrographite electrodes modified by physical adsorption of bilirubin oxidases from Myrothecium verrucaria. The existence of an alternative resting form of the enzyme is validated. The effect on the catalytic cycle of temperature, pH and the presence of halogens in the buffer was investigated. Previous results on the electrochemistry of bilirubin oxidase and on the impact of the presence of halogens are reviewed and reinterpreted
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