• Home
  • Search Results
  • B-N polymer embedded iron(0) nanoparticles as highly active and long lived catalyst in the dehydrogenation of ammonia borane.

B-N polymer embedded iron(0) nanoparticles as highly active and long lived catalyst in the dehydrogenation of ammonia borane.

Journal of nanoscience and nanotechnology (2013-08-02)
Sibel Duman, Onder Metin, Saim Ozkar
ABSTRACT

B-N polymer embedded iron(0) nanoparticles (NPs) were in-situ generated from the reduction of iron(III) acetylacetonate during the dehydrogenation of ammonia borane (AB) in THF solution at 40.0 +/- 0.5 degrees C. The iron(0) NPs could be isolated as powder from the reaction solution by centrifugation and characterized by UV-Vis, TEM, and XRD. They are redispersible in polar solvent such as THF and yet highly active catalysts in the dehydrogenation of AB providing a TOF value of 202 h(-1) at 40.0 +/- 0.5 degrees C. The catalytic activity of iron(0) NPs compare well with those of the known homogenous and heterogeneous precious metal catalysts reported so far. They are also long-life catalysts in the dehydrogenation of AB providing 1410 turnovers over 18 h at 40.0 +/- 0.5 degrees C. The poisoning experiments using carbon disulfide show that the dehydrogenation of AB catalyzed by iron(0) NPs is a heterogeneous catalysis. The catalytic dehydrogenation of AB in the presence of iron(0) NPs was followed by measuring the volume of hydrogen generated and by 11B-NMR spectroscopy. Our report also includes the results of a detailed kinetic study on the catalytic dehydrogenation of AB depending on the catalyst concentration, substrate concentration, and temperature. The dehydrogenation of AB produces sparingly soluble B-N polymers which provide just enough stability to the iron(0) NPs. The co-precipitation of some iron(0) NPs with the sparingly soluble polymers causes a slight decrease in the catalytic activity toward the end of dehydrogenation. However, iron(0) NPs embedded in B-N polymers appear to be an efficient catalyst in hydrogen generation from ammonia borane at moderate temperature.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Ammonia solution, 7 N in methanol
Sigma-Aldrich
Ammonia, anhydrous, ≥99.98%
Sigma-Aldrich
Iron, ≥99%, reduced, powder (fine)
Sigma-Aldrich
Boron nitride, powder, ~1 μm, 98%
Sigma-Aldrich
Hydrogen, ≥99.99%
Sigma-Aldrich
Ammonia solution, 2.0 M in ethanol
Sigma-Aldrich
Carbonyl iron, ≥97% Fe basis
Sigma-Aldrich
Iron, powder, −325 mesh, 97%
Sigma-Aldrich
Ammonia solution, 0.4 M in THF
Sigma-Aldrich
Ammonia solution, 0.4 M in dioxane
Sigma-Aldrich
Ammonia solution, 2.0 M in methanol
Sigma-Aldrich
Iron, powder, <10 μm, ≥99.9% trace metals basis
Sigma-Aldrich
Ammonia solution, 4 M in methanol
Sigma-Aldrich
Iron, puriss. p.a., carbonyl-Iron powder, low in magnesium and manganese compounds, ≥99.5% (RT)
Sigma-Aldrich
Ammonia solution, 2.0 M in isopropanol
Sigma-Aldrich
Iron, chips, 99.98% trace metals basis
Sigma-Aldrich
Iron, granular, 10-40 mesh, >99.99% trace metals basis
Sigma-Aldrich
Iron, foil, thickness 0.1 mm, ≥99.9% trace metals basis
Sigma-Aldrich
Iron, flakes, ≥99.99% trace metals basis
Sigma-Aldrich
Iron, foil, thickness 0.25 mm, ≥99.99% trace metals basis
Sigma-Aldrich
Iron, wire, diam. 1.0 mm, ≥99.9% trace metals basis
Sigma-Aldrich
Iron, wire, diam. 1.0 mm, ≥99.99% trace metals basis
Sigma-Aldrich
Iron, rod, diam. 6.3 mm, 99.98% trace metals basis
Iron, IRMM®, certified reference material, 0.5 mm wire
Sigma-Aldrich
Iron, wire, diam. 0.5 mm, ≥99.9% trace metals basis