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

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 ratio

Oxidation of Glycerol with Unactivated Electroless CuNiMoP Catalyst

Unannealed CuNiMoP electrocatalyst was found active in electrochemical oxidation of glycerol, providing over 60% conversion without optimization. Prompted by this result, the same catalyst was investigated for the thermochemical oxidation of glycerol. For the thermochemical oxidation of glycerol using the as-deposited electroless CuNiMoP catalyst, a 23 full factorial design of experiments (two level factorial experiment design with three factors) to assess the influence of temperature (A), reaction time (B) and pressure (C). The major reaction products detected by high performance liquid chromatography (HPLC) were glyceric, hydroxypyruvic, tartronic, oxalic and formic acids. The factors found to be most significant for the production of glyceric and tartronic acids were A, B, C, AB and BC. The highest percent conversion obtained for 30-min and 60-min catalysts was 10.6% and 9.4%, respectively. The presence of lactic acid was observed only for the 60-min as-deposited electroless CuNiMoP/Al2O3 catalyst. The results suggest the feasibility of an inexpensive catalyst based on non-noble metals for the thermochemical oxidation of glycerol through the electroless deposition technique. Some differences exist between the thermochemical and electrochemical product selectivity of the CuNiMoP catalyst, and reasons are suggested for the observed differences