Dehydrogenation of Ammonia Borane with transition metal-doped CoeB alloy catalysts R. Fernandes a, *, N. Patel a , A. Miotello a , R. Jaiswal c , D.C. Kothari b,c a Dipartimento di Fisica, Universita ` degli Studi di Trento, I-38123 Povo (Trento), Italy b Department of Physics, University of Mumbai, Vidyanagari, Santacruz, Mumbai 400 098, India c National Centre for Nanomaterials and Nanotechnology, University of Mumbai, Vidyanagari, Santacruz, Mumbai 400 098, India article info Article history: Received 26 August 2011 Received in revised form 19 October 2011 Accepted 28 October 2011 Available online 30 November 2011 Keywords: H 2 generation Hydrolysis Ammonia Borane Doped CoeB catalyst Surface area abstract The catalytic performance of transition metal-doped CoeB ternary alloys were tested for H 2 generation by hydrolysis of Ammonia Borane (AB). Chemical reduction method was used to dope CoeB catalyst with various transition metals, namely Cu, Cr, Mo, and W, using their corresponding metal salts. All transition metals induce significant promoting effects on the CoeB catalyst by increasing the H 2 generation rate by about 3e6 times as compared to the undoped catalyst. The effect of metal dopant concentration on overall catalyst structure, surface morphology, and catalytic efficiency were examined by varying the metal/ (Co þ metal) molar ratio. Characterizations such as XPS, XRD, SEM, BET surface area measurement, and particle size analysis were carried out to understand the promoting role of each dopant metal during AB hydrolysis. Dopant transition-metals, in either oxidized or/ and metallic state, act as an atomic barrier to avoid CoeB particle agglomeration thus preserving the effective surface area. In addition, the oxidized species such as Cr 3þ , Mo 4þ , and W 4þ , act as Lewis acid sites to enhance the absorption of OH  group to further assist the hydrolysis reaction over alloy catalysts. The promoting nature of transition metal dopants in CoeB alloy powders is demonstrated by the evaluated low activation energy of the rate limiting step and high H 2 generation rate (2460 ml H 2 min 1 (g of catalyst) 1 for CoeMoeB) in the hydrolysis of AB. Copyright ª 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. 1. Introduction An energy economy based on hydrogen may prove to be a sustainable solution to growing concerns related to increasing energy requirement and greenhouse gas emissions [1]. However, the necessity to develop an efficient and safe system for hydrogen storage is a major hurdle that must be overcome to enable the use of hydrogen as an alternative energy carrier [2]. Chemical hydrides (NaBH 4 , NH 3 BH 3 , LiBH 4 , NaH, KBH 4 , etc.) with high hydrogen storage capacity in terms of gravimetric and volumetric efficiencies are the most prospective contenders to supply pure hydrogen at room temperature [3e5]. Ammonia Borane (NH 3 BH 3 , (AB)) with high gravimetric storage (19.6 wt. %) ability is the most prospective contenders to supply pure hydrogen for portable and on-board application at room temperature [6,7]. AB can produce hydrogen by hydrolysis reaction with high solubility limit and stability in aqueous medium [8,9]. * Corresponding author. University of Trento, Department of Physics, Via Sommarive 14, Povo, Trento I-38123, Italy. Tel.: þ39 (0) 461882012; fax: þ39 (0) 461881696. E-mail address: fernandes@science.unitn.it (R. Fernandes). Available online at www.sciencedirect.com journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy 37 (2012) 2397 e2406 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.2011.10.119