MOLECULAR CATALYSIS, vol.430, pp.29-35, 2017 (SCI-Expanded)
Ruthenium(0) nanoparticles supported on nanohafnia (Ru-0/HfO2) were prepared by impregnation of ruthenium(III) cations on the surface of hafnia followed by their reduction with sodium borohydride at room temperature. Ru-0/HfO2 samples were isolated from the reaction solution by centrifugation and characterized by a combination of advanced analytical techniques including ICP-OES, BET, XRD, SEM-EDS, TEM, XPS. The catalytic activity of Ru-0/HfO2 samples with various ruthenium loading in the range 0.5-5.0% wt Ru was tested in hydrogen generation from the hydrolysis of ammonia borane (AB) at room temperature. The highest catalytic activity was achieved by using 4.0% wt ruthenium loaded nanohafnia providing a turnover frequency of 170 min(-1) and an unprecedented catalytic life time (175,600 turnovers) in hydrogen generation from the hydrolysis of AB at 25.0 +/- 0.1 degrees C. Ru-0/HfO2 is reusable catalyst preserving 75% of the initial catalytic activity even after the fifth reuse in hydrogen generation from the hydrolysis of AB at room temperature. Our report also includes the results of kinetic studies depending on the catalyst concentration and temperature to determine the activation energy (E-a = 65 +/- 3 kJ/mol) for hydrolytic dehydrogenation of AB. (C) 2016 Elsevier B.V. All rights reserved.