title: Ruthenium(0) nanoparticles supported on multiwalled carbon nanotube as highly active catalyst for hydrogen generation from ammonia-borane.
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 H₂ 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 °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.
authors.affiliation: Department of Chemistry, Middle East Technical University, 06800 Ankara, Turkey.
authors.forename: Serdar
authors.initials: S
authors.lastname: Akbayrak
authors.forename: Saim
authors.initials: S
authors.lastname: Ozkar
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D001880:Boranes / Q000737:chemistry*; D002384:Catalysis; D006859:Hydrogen / Q000737:chemistry* / Q000302:isolation & purification; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D012428:Ruthenium / Q000737:chemistry*; D013696:Temperature
chemical_list: D001880:Boranes; D037742:Nanotubes, Carbon; D000641:Ammonia; D012428:Ruthenium; D006859:Hydrogen