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    Rhodium(0) nanoparticles supported on nanotitania as highly active catalyst in hydrogen generation from the hydrolysis of ammonia borane
    (Royal Soc Chemistry, 2014) Akbayrak, Serdar; Gençtürk, Serap; Morkan, İzzet; Özkar, Saim
    Rhodium(0) nanoparticles supported on the surface of titanium dioxide (Rh(0)@TiO2) were in situ generated from the reduction of rhodium(III) ions impregnated on nanotitania during the hydrolysis of ammonia borane. They were isolated from the reaction solution by centrifugation and characterized by a combination of advanced analytical techniques. The results show that (i) highly dispersed rhodium(0) nanoparticles with sizes in the range 1.3-3.8 nm were formed on the surface of titanium dioxide, (ii) Rh(0)@TiO2 shows high catalytic activity in hydrogen generation from the hydrolysis of ammonia borane with a turnover frequency value up to 260 min(-1) at 25.0 +/- 0.1 degrees C, (iii) the results of kinetic studies on the hydrogen generation from the hydrolysis of ammonia borane were also reported including the activation energy of 65.5 +/- 2 kJ mol(-1) for this reaction.
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    Ruthenium(0) nanoparticles supported on nanotitania as highly active and reusable catalyst in hydrogen generation from the hydrolysis of ammonia borane
    (Pergamon-Elsevier Science Ltd, 2014) Akbayrak, Serdar; Tanyıldızı, Seda; Morkan, İzzet; Özkar, Saim
    Ruthenium(0) nanoparticles supported on the surface of titania nanospheres (Ru(0)/TiO2) were in situ generated from the reduction of ruthenium(III) ions impregnated on nanotitania during the hydrolysis of ammonia borane. They were isolated from the reaction solution by centrifugation and characterized by a combination of advanced analytical techniques. The results reveal that highly dispersed ruthenium(0) nanoparticles of size in the range 1.5-3.3 nm were formed on the surface of titania nanospheres. Ru(0)/TiO2 show high catalytic activity in hydrogen generation from the hydrolysis of ammonia borane with a turnover frequency value up to 241 min(-1) at 25.0 +/- 0.1 degrees C. They provide unprecedented catalytic lifetime measured by total turnover number (TTO = 71,500) in hydrogen generation from the hydrolysis of ammonia borane at 25.0 +/- 0.1 degrees C. The report also includes the results of kinetic study on the catalytic hydrolysis of ammonia borane depending on the temperature to determine the activation energy of the reaction (E-a = 70 +/- 2 kJ/mol) and the catalyst concentration to establish the rate law of the reaction. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.