Hydrogen adsorption capacities of various alumina-pillared clays have been studied. The starting material for the preparation of the samples was a natural montmorillonite, which was intercalated with solutions of hydrolysed aluminium, at various Al concentration/clay weight ratios, and then calcined at various temperatures. The results of the adsorption at 77 K indicate that there is a relation between the hydrogen uptake and the microporous volume of the pillared clays. Equilibrium adsorption data were analysed using the Freundlich, Langmuir and Toth isotherm models, in order to investigate the heterogeneity of the materials. (c) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.