Research Information System
RSC ADVANCES, vol.6, no.104, pp.102035-102042, 2016 (SCI-Expanded)
Magnetic ferrite nanopowders were coated with polydopamine which is inert against the hydrolysis of ammonia borane. Coating of ferrite powders was achieved by pH-induced self-polymerization of dopamine hydrochloride at room temperature. Palladium(0) nanoparticles supported on polydopamine coated ferrite (Pd-0/PDA-Fe3O4) were prepared by impregnation of palladium(II) ions on the surface of PDA-Fe3O4 followed by their reduction with sodium borohydride in aqueous solution at room temperature. Magnetically isolable Pd-0/PDA-Fe3O4 catalysts were characterized by a combination of advanced analytical techniques. The results reveal that palladium nanoparticles with an average size of 2.0 +/- 0.4 nm are well dispersed on polydopamine layer with a thickness of 3.0 +/- 0.5 nm on the surface of ferrite nanopowders. Pd-0/PDA-Fe3O4 with a palladium loading of 3.81% wt was found to be a highly active and reusable catalyst in hydrogen generation from the hydrolysis of ammonia borane with a turnover frequency value of 14.5 min(-1) at 25.0 +/- 0.1 degrees C. Magnetically isolable Pd-0/PDA-Fe3O4 catalysts preserve their initial catalytic activity even after the tenth use providing the release of 3 equivalent H-2 per mole of ammonia borane. The report also includes the results of kinetic studies on the hydrolytic dehydrogenation of ammonia borane performed at various temperatures and different catalyst concentrations.