International Journal of Hydrogen Energy 33 (2008) 287 – 292 www.elsevier.com/locate/ijhydene Pd-C powder and thin film catalysts for hydrogen production by hydrolysis of sodium borohydride N. Patel ∗ , B. Patton, C. Zanchetta, R. Fernandes, G. Guella, A. Kale, A. Miotello Dipartimento di Fisica, Università degli Studi di Trento, I-38050 Povo, Trento, Italy Received 18 June 2007; accepted 9 July 2007 Available online 28 August 2007 Abstract In this work we study the hydrogen generation by catalytic hydrolysis of alkaline NaBH 4 solution employing Pd-supported on carbon powder (Pd/C) as well as in form of Pd and Pd–C thin films synthesized by pulsed laser deposition (PLD). Two sets of samples were prepared: (1) pure Pd catalyst films which were bombarded with Ar + ions at different ions fluence in order to increase the surface roughness; (2) highly irregular C film were deposited by using different Ar pressure in the PLD chamber prior to deposition of the Pd film to further increase the surface area for the active Pd catalyst. Surface morphology was studied by using scanning electron microscopy (SEM) and atomic force microscopy (AFM) while compositional analysis was performed by using energy dispersive spectroscopy (EDS). Cone like structure on the surface of the Pd film developed by Ar + ion bombardment was not efficient to enhance the catalytic activity of the Pd. Pd/C films showed higher catalytic activity in comparison to Pd/C powders when the same amount of catalyst is used. The results are discussed in relation to the morphology of the C-films.  2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved. Keywords: Hydrogen generation; Catalyst; Sodium borohydride; Pd/C; Thin film 1. Introduction In the next few decades, global energy resources will be fac- ing major growing demand pressures due to increasing require- ment for energy. Hydrogen is very important as future energy vector whose application areas range from the vehicular trans- port to energy batteries. Pure hydrogen is adopted as the fuel in proton exchange membrane fuel cell (PEMFC) [1]. However, on industrial level, H 2 is mostly produced by steam reforming of natural gas which, however, contains carbon contamination (CO 2 and CO). The presence of carbon monoxide (even at ppm level) in the hydrogen gas reduces the performance of PEMFC due to catalyst poisoning [2]. Therefore, especially for the mo- bile application, a fast and clean hydrogen supply method is required. Chemical hydrides (NaBH 4 , NaH, LiH, KBH 4 , NaAlH 4 , etc.) are very attractive materials for pure hydrogen supply to the fuel cells at room temperature [3]. Large amount of pure ∗ Corresponding author. Tel.: +39 0461 882012; fax: +39 0461 881696. E-mail address: patel@science.unitn.it (N. Patel). 0360-3199/$ - see front matter  2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.ijhydene.2007.07.018 hydrogen gas is released during the hydrolysis of chemical hy- drides in presence of appropriate catalysts. Sodium borohydride (NaBH 4 ) is one of the most preferred hydride due to: (i) its high hydrogen storage capacity (10.9 wt%), (ii) the good chemical stability of its alkaline solutions, (iii) the optimal control on H 2 generation rate by supported catalysts, (iv) its high conversion rate even at low temperature, and (v) the reaction by-product, borax, is environmentally clean and can, in principle, be recy- cled [4]. The hydrolysis reaction of the sodium borohydride is as follows: NaBH 4 + 2H 2 O catalyst -→ NaBO 2 + 4H 2 . (1) Hydrolysis reaction carried out in heterogeneous conditions by using metal catalysts was found to be well controlled and efficient. Catalysts like Ru supported on anion-exchange resin [4], fluorinated Mg-based alloy [5], Pt supported on carbon [6], PtRu supported on metal oxide [7], Raney Ni and Co, and even nickel and cobalt borides [8], are generally used to accelerate the hydrolysis reaction of the NaBH 4 . Palladium is one of the most attractive catalyst for the dissociation of H 2 molecules and palladium compounds are generally involved