Palladium(0) nanoparticles supported on polydopamine coated Fe3O4 as magnetically isolable, highly active and reusable catalysts for hydrolytic dehydrogenation of ammonia borane


Manna J., Akbayrak S., ÖZKAR S.

RSC ADVANCES, cilt.6, ss.102035-102042, 2016 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 6 Konu: 104
  • Basım Tarihi: 2016
  • Doi Numarası: 10.1039/c6ra23007e
  • Dergi Adı: RSC ADVANCES
  • Sayfa Sayıları: ss.102035-102042

Özet

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.