Hydrogen uptake in nano-sized metallic and bimetallic clusters
Date
2010-08-02
Authors
Mohammad Suleiman Shtaya
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Abstract
<p>Size selective preparations of nano-meter-sized clusters in the range of 2-6 nm, such as Palladium clusters and bimetallic clusters (PdMg, PdNi and PdFe) will be presented. The preparation is performed by electrochemical method where a simple two electrodes cell is used; to prevent undesired agglomeration the clusters were stabilized in matrix such as: surfactant shell e.g. tetra-octyl- ammonium bromide which is used as electrolyte and stabiliser, or polymers matrix as Teflon AF and PMMA.<br />
The interaction of hydrogen with these clusters from both kinetic and thermodynamic point of view was studied. Results on the hydrogen uptake, storage, behaviour in nano-sized metallic clusters; using volumetric measurements, gravimetric measurements will be presented. In situ X-ray synchrotrons measurements (XRD) and Extended X-Ray Fine Absorption Structure (EXAFS) measurements during hydrogen loading shows the formation of the Pd hydride phase for cubic clusters indicating an (α-ά) phase transition, while no (α-ά) phase transition was observed for icosahedral clusters.</p>
<p>Size selective preparations of nano-meter-sized clusters in the range of 2-6 nm, such as Palladium clusters and bimetallic clusters (PdMg, PdNi and PdFe) will be presented. The preparation is performed by electrochemical method where a simple two electrodes cell is used; to prevent undesired agglomeration the clusters were stabilized in matrix such as: surfactant shell e.g. tetra-octyl- ammonium bromide which is used as electrolyte and stabiliser, or polymers matrix as Teflon AF and PMMA.<br /> The interaction of hydrogen with these clusters from both kinetic and thermodynamic point of view was studied. Results on the hydrogen uptake, storage, behaviour in nano-sized metallic clusters; using volumetric measurements, gravimetric measurements will be presented. In situ X-ray synchrotrons measurements (XRD) and Extended X-Ray Fine Absorption Structure (EXAFS) measurements during hydrogen loading shows the formation of the Pd hydride phase for cubic clusters indicating an (α-ά) phase transition, while no (α-ά) phase transition was observed for icosahedral clusters.</p>
<p>Size selective preparations of nano-meter-sized clusters in the range of 2-6 nm, such as Palladium clusters and bimetallic clusters (PdMg, PdNi and PdFe) will be presented. The preparation is performed by electrochemical method where a simple two electrodes cell is used; to prevent undesired agglomeration the clusters were stabilized in matrix such as: surfactant shell e.g. tetra-octyl- ammonium bromide which is used as electrolyte and stabiliser, or polymers matrix as Teflon AF and PMMA.<br /> The interaction of hydrogen with these clusters from both kinetic and thermodynamic point of view was studied. Results on the hydrogen uptake, storage, behaviour in nano-sized metallic clusters; using volumetric measurements, gravimetric measurements will be presented. In situ X-ray synchrotrons measurements (XRD) and Extended X-Ray Fine Absorption Structure (EXAFS) measurements during hydrogen loading shows the formation of the Pd hydride phase for cubic clusters indicating an (α-ά) phase transition, while no (α-ά) phase transition was observed for icosahedral clusters.</p>