Methanolysis of ammonia borane catalyzed by magnetically isolable RHODIUM(0) nanoparticles

Abstract

This article reports the preparation and employment of rhodium (0) nanoparticles (Rh0NPs) on the surface of magnetite nanospheres, denoted as Rh0@Fe3O4, as magnetically isolable nanocatalyst in the methanolysis of ammonia borane (MAB). The monodispersed Fe3O4 nanospheres are fabricated by a simple technique and used as nanosupport for Rh0NPs which are well stabilized and homogeneously distributed on the surface of nanospheres with a mean particle size of 2.8 ± 0.5 nm. The as-synthesized Rh0@Fe3O4 has a remarkable TOF value of 184 min−1 in the MAB to produce H2 gas in RT. Most of all, Rh0@Fe3O4 nanocatalyst can be reused, evolving 3.0 mol of H2 gas for a mole of AB, keeping 100% of its initial activity even in the fourth reuse of MAB at 25 °C. Recovery of the Rh0@Fe3O4 nanocatalyst can be accomplished by simply approaching an external magnet, which eliminates many laborious catalyst removal steps in catalytic reactions. Reported are the outcomes of kinetic investigation, done by altering the concentration of substrate and catalyst together with temperature. Kinetic studies reveal that the catalytic MAB shows dependence on the concentration of reactants and temperature.