Monodisperse nickel nanoparticles in the solvent-free dehydrogenation of dimethylamine borane

Abstract

Monodisperse 1.9 nm Ni nanoparticles (NPs) were in-situ synthesized by simple mechanical stirring of solvent-free mixtures of a nickel(II) chloride and dimethylamine borane (DMAB) under inert gas atmosphere at 25.0 ± 0.1 °C. They were found to be highly active catalyst in hydrogen generation from the solvent-free dehydrogenation of DMAB; totally one equivalent of hydrogen gas per DMAB were generated at low catalyst loading at room temperature. 11B-NMR study of the reaction showed that hydrogen evolution likely takes place through the formation of BH2(μ-Me2N)(μ-H)BH2 (dimethylamino diborane) and (Me2N)2BH (bis(dimethylamino) borane). In this reaction, DMAB was used as both reducing and stabilizing agent. The detailed kinetics of the solvent-free dehydrogenation of DMAB catalyzed by monodisperse Ni NPs were shown to be dependent on catalyst and substrate loading and temperature.