Zeolite confined copper(0) nanoclusters as cost-effective and reusable catalyst in hydrogen generation from the hydrolysis of ammonia-borane

Herein we report the development of a cost-effective nanocluster catalyst for the hydrolytic dehydrogenation of ammonia-borane which is considered to be one among the new hydrogen storage materials. Zeolite confined copper(0) nanoclusters were prepared by the ion-exchange of Cu2+ ions with the extra framework Na+ ions in zeolite-Y followed by reduction of the Cu2+ ions within the cavities of zeolite with sodium borohydride in aqueous solution and characterized by HR-TEM, XRD, XPS, SEM, EDX, ICP-OES, Raman spectroscopy and N-2 adsorption-desorption technique. Zeolite confined copper(0) nanoclusters are found to be active catalysts in the hydrolysis of ammonia-borane even at low temperatures (<= 15 degrees C) and stable enough for being isolated as solid materials. They provide 1300 turnovers in hydrogen generation from the hydrolysis of ammonia-borane at room temperature. The average value of turnover frequency is 46.5 h(-1) for the same reaction. More importantly, zeolite confined copper(0) nanoclusters were found to be isolable, bottleable and reusable catalysts in the hydrolytic dehydrogenation of ammonia-borane; even at fifth run the complete release of hydrogen from the hydrolysis of ammonia-borane at room temperature is achieved. The work reported here also includes the full experimental details for the collection of a wealth of kinetic data to determine the activation energy and the effect of catalyst concentration on the rate for the catalytic hydrolysis of ammonia-borane. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.