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Activity of varying compositions of CoeNieP catalysts for the methanolysis of ammonia borane

Amoo, Kehinde O. and Onyeozili, Edith N. and Kalu, Egwu E. and Omoleye, James and Efeovbokhan, Vincent Enon (2016) Activity of varying compositions of CoeNieP catalysts for the methanolysis of ammonia borane. i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y, xxx. pp. 1-15.

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Abstract

Various compositions of CoeNieP catalysts supported on a palladium-activated Al2O3 (Pd eAl2O3) substrate were synthesized, characterized and investigated for catalytic methanolysis of ammonia-borane (AB, H3NBH3). The CoeNieP/PdeAl2O3 catalysts were synthesized by polymer-stabilized Pd nanoparticle-catalyzation and activation of the Al2O3 substrate support and the electroless deposition of cobalt-nickel (CoeNi) metal particles on the surface of the Al2O3 support for a plating time of 30 min. The CoeNieP/PdeAl2O3 catalysts are stable enough to be isolated as solid materials and characterized by X-ray Diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDS) and Scanning Electron Microscopy (SEM). At 40 ± 0.5 �C, the isolable, re-dispersible and reusable catalysts were found active in the methanolytic dehydrogenation of ammonia-borane retaining up to 65% of its initial activity after five cycles. Rates of hydrogen evolution were used to determine the kinetics of methanolysis reaction. The ranges of examined catalyst particle amounts, AB concentrations and temperatures were 15.75e63 mg, 50e200 mM, and 30e55 �C, respectively. Hydrogen desorption was identified as the rate controlling step in the methanolysis reaction and using the data, the kinetic rate constant (€kH2 ), the hydrogen desorption equilibrium constant (KH2 ), and the overall equilibrium constant (K1) parameters in a LangmuireHinshelwood rate expression were determined to be 1.4 mol/g-cat. s, 1.5918 L/ mol and 1.5986 L/mol, respectively. Activation parameters such as enthalpy of activation (DH), entropy of activation (DS), and activation energy (Ea) that were obtained by Eyring and Arrhenius equations are reported for the various catalyst ratios

Item Type: Article
Uncontrolled Keywords: Cobalt Nickel Methanolysis Ammonia-borane Electroless LangmuireHinshelwood
Subjects: T Technology > T Technology (General)
T Technology > TP Chemical technology
Divisions: Faculty of Engineering, Science and Mathematics > School of Engineering Sciences
Depositing User: Mrs Hannah Akinwumi
Date Deposited: 15 Jun 2017 12:03
Last Modified: 15 Jun 2017 12:03
URI: http://eprints.covenantuniversity.edu.ng/id/eprint/8230

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