Hydroxyapatite-supported cobalt(0) nanoclusters as efficient and cost-effective catalyst for hydrogen generation from the hydrolysis of both sodium borohydride and ammonia-borane


Rakap M., ÖZKAR S.

CATALYSIS TODAY, cilt.183, ss.17-25, 2012 (SCI İndekslerine Giren Dergi)

  • Cilt numarası: 183 Konu: 1
  • Basım Tarihi: 2012
  • Doi Numarası: 10.1016/j.cattod.2011.04.022
  • Dergi Adı: CATALYSIS TODAY
  • Sayfa Sayısı: ss.17-25

Özet

Herein, we report the preparation, characterization, and catalytic use of cobalt(0) nanoclusters supported on hydroxyapatite in the hydrolysis of both basic sodium borohydride and ammonia-borane solutions. They were prepared in situ from the reduction of cobalt(II) ions adsorbed on hydroxyapatite with sodium borohydride. Hydroxyapatite-supported cobalt(0) nanoclusters were stable enough to be isolated as solid material and characterized by inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray diffraction (XRD), attenuated total reflectance infrared (ATR-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) spectroscopy. They are isolable, redispersible, highly active, and cost-effective catalysts for hydrogen generation from the hydrolysis of both sodium borohydride and ammonia-borane even at low concentrations and temperature, providing 25,600 and 7400 turnovers and maximum hydrogen generation rates of 5.0 and 2.2 LH2 min(-1) (gCo)(-1) by the hydrolysis of NaBH4 and H3NBH3 at 25.0 +/- 0.1 degrees C, respectively. Hydroxyapatite-supported cobalt(0) nanoclusters provide activation energy of 53 +/- 2 kJ/mol for the hydrolysis of sodium borohydride and 50 +/- 2 kJ/mol for the hydrolysis of ammonia-borane. (C) 2011 Elsevier B. V. All rights reserved.