PVP-stabilized nickel(0) nanoparticles as catalyst in hydrogen generation from the methanolysis of hydrazine borane or ammonia borane

Herein we report the results of a detailed study on the in-situ generation of poly(N-vinyl-2-pyrrolidone) (PVP) stabilized nickel(0) nanoparticles and their catalytic activity in methanolysis of hydrazine borane and ammonia borane. PVP-stabilized nickel(0) nanoparticles with an average particle size of 3.0 +/- 0.7 nm were in-situ generated from the reduction of nickel(II) 2-ethylhexanoate during the methanolysis of hydrazine borane in the presence of PVP at room temperature. Polymer stabilized nickel(0) nanoparticles could be isolated from the solution by centrifugation and characterized by UV-vis spectroscopy, XPS, TEM, and SAED. PVP-stabilized nickel(0) nanoparticles are highly active and long lived catalyst in hydrogen generation from the methanolysis of hydrazine borane and ammonia borane at ambient temperature. The results of kinetic study reveal that the methanolysis is first order with respect to catalyst concentration and zero order regarding to substrate concentration in both cases. PVP-stabilized nickel(0) nanoparticles provide 14,500 turnovers in hydrogen generation from the methanolysis of hydrazine borane and 5300 turnovers from the methanolysis of ammonia borane. They also provide an initial turnover frequency of 35.6 and 12.1 min(-1) for the catalytic methanolysis of hydrazine borane and ammonia borane, respectively. (C) 2014 Elsevier B.V. All rights reserved.