Ruthenium(0) Nanoparticles Supported on Multiwalled Carbon Nanotube As Highly Active Catalyst for Hydrogen Generation from Ammonia-Borane


Akbayrak S., ÖZKAR S.

ACS APPLIED MATERIALS & INTERFACES, vol.4, no.11, pp.6302-6310, 2012 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 4 Issue: 11
  • Publication Date: 2012
  • Doi Number: 10.1021/am3019146
  • Title of Journal : ACS APPLIED MATERIALS & INTERFACES
  • Page Numbers: pp.6302-6310
  • Keywords: ruthenium nanoparticles, carbon nanotube, heterogeneous catalyst, hydrogen generation, ammonia borane, hydrolysis, METAL NANOCLUSTER FORMATION, HYDROLYTIC DEHYDROGENATION, PALLADIUM(0) NANOCLUSTERS, RHODIUM(0) NANOCLUSTERS, STABILIZED RUTHENIUM(0), THERMAL-DECOMPOSITION, REUSABLE CATALYST, STORAGE, NUCLEATION, METHANOLYSIS

Abstract

Ruthenium(0) nanoparticles supported on multiwalled carbon nanotubes (Ru(0)@MWCNT) were in situ formed during the hydrolysis of ammonia-borane (AB) and could be isolated from the reaction solution by filtration and characterized by ICP-OES, XRD, TEM, SEM, EDX, and XPS techniques. The results reveal that ruthenium(0) nanoparticles of size in the range 1.4-3.0 nm are well-dispersed on multiwalled carbon nanotubes. They were found to be highly active catalyst in hydrogen generation from the hydrolysis of AB with a turnover frequency value of 329 min(-1). The reusability experiments show that Ru(0)@MWCNTs are isolable and redispersible in aqueous solution; when redispersed they are still active catalyst in the hydrolysis of AB exhibiting a release of 3.0 equivalents of H-2 per mole of NH3BH3 and preserving 41% of the initial catalytic activity even after the fourth run of hydrolysis. The lifetime of Ru(0)@MWCNTs was measured as 26400 turnovers over 29 h in the hydrolysis of AB at 25.0 +/- 0.1 degrees C before deactivation. The work reported here also includes the kinetic studies depending on the temperature to determine the activation energy of the reaction (E-a = 33 +/- 2 kJ/mol) and the effect of catalyst concentration on the rate of the catalytic hydrolysis of AB, respectively.