Influence of the method of synthesis on hydrogen adsorption properties of mesoporous binary B 2 O 3 /Al 2 O 3 gel systems Agnieszka Marty1a a, *, Barbara Olejnik a , Piotr Kirszensztejn b , Robert Przekop b a Institute of Non-ferrous Metals, Branch in Poznan, Central Laboratory of Batteries and Cells, ul. Forteczna 12, 61-362 Poznan, Poland b Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznan, Poland article info Article history: Received 22 February 2011 Received in revised form 12 April 2011 Accepted 13 April 2011 Available online 13 May 2011 Keywords: Modified alumina B 2 O 3 Hydrogen adsorption abstract Three series of binary oxide systems B 2 O 3 /Al 2 O 3 were prepared and the effect of alumina on dispersion of boron (B 2 O 3 ) component was investigated. The aim of the study was to achieve a maximum dispersion of B 2 O 3 in the Al 2 O 3 a gel matrix that would lead to increased sorption capacity on boron oxide. Many attempts were made to establish the preparation conditions that would lead to a maximum dispersion of B 2 O 3 in the Al 2 O 3 gel matrix needed to increase the hydrogen sorption capacity on boron oxide. The systems were characterized by X-ray diffraction, SEM, TEM and low temperature nitrogen adsorption. Hydrogen adsorption was tested in the volumetric system. Results of the study showed that the amount of hydrogen adsorbed on B 2 O 3 depended not only on the surface area of the system but also on the separation of B 2 O 3 domains in Al 2 O 3 gel network. Irrespective of the method of synthesis of the binary oxide system, the dispersion of B 2 O 3 phase reflected in the amount of hydrogen adsorbed was the highest for the systems of the lowest B/Al molar ratios studied, i.e. for B/Al ¼ 0.25. Copyright ª 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. 1. Introduction Hydrogen can be made available onboard vehicles in containers of compressed or liquefied H 2 , or in the solid by chemisorption or physisorption. Although each method has some desirable features, no approach has as yet satisfied all requirements as to the efficiency, size, weight, cost and safety for transportation or use. Gas-on-solid adsorption is an inherently safe and potentially high energy density hydrogen storage method that should be more energy efficient than the storage in the form of either chemical or metal hydrides or as compressed gas. Hydrogen storage using physisorption requires lower desorption temperature than the storage of chemical bonded or chemisorbed hydrogen. Therefore, the hydrogen storage properties of high surface area active carbons (AC) have been extensively studied [1e4]. Using the pseudopotential density functional calculation [5e7] the heat of hydrogen adsorption on B 2 O 3 and HBO 2 was calculated as 13 kJ/mol and that on H 3 BO 3 as 10 kJ/mol. S.-H. Jhi et al. [6] predicted and experimentally confirmed the boron materials suitability for hydrogen physisorption with 30% higher TD (desorption temperature) than AC. The choice of boron oxide for structural modification followed from the fact it has locally layered structures (similar to graphite) and ionic bonding and because it can form a porous glassy network, which gives a potential for high surface area and relatively high adsorption energy. Discovery of these strong phys- isorbents is a milestone in the development of new classes of * Corresponding author. E-mail address: agnieszka.martyla@claio.poznan.pl (A. Marty1a). Available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy 36 (2011) 8358 e8364 0360-3199/$ e see front matter Copyright ª 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.ijhydene.2011.04.091