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

Abstract

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 Cu 2+ ions with the extra framework Na + ions in zeolite-Y followed by reduction of the Cu 2+ 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 °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.