Catalytic Hydrolysis of Ammonia Borane Using Co-B Nanoparticles Embedded In Mesoporous Silica Particles: a Very Efficient Catalyst for Hydrogen Production

Tuesday, October 18, 2011: 2:35 PM
207 A/B (Minneapolis Convention Center)
Nainesh Patel1, Rupali Dholam2, Renuka Jaiswal2, Namdeo B. Lihitkar2, Rohan Fernandes1, Antonio Miotello1 and Dushyant C. Kothari3, (1)Physics, UniversitÓ degli Studi di Trento, Povo (Trento), Italy, (2)Centre for Nanosciences & Nanotechnology, University of Mumbai,, Mumabi, India, (3)Centre for Nanosciences & Nanotechnology, University of Mumbai, Mumabi, India

Ammonia Borane (AB), with high hydrogen storage capacity (19.5 wt.%), is predicted  to be possibly a future fuel for providing pure H2 to fuel cell at room temperature for on-board and portable applications. However, a heterogeneous catalyst plays a vital role for first initiating and then controlling H2 production during hydrolysis reactions. Thus, the present work is focused to develop nano-catalyst to be used for dehydrogenation reactions of AB. Firstly, mesoporous silica nanoparticles (~ 100 nm) with pore size of ~ 3 nm were synthesis by hydrolysis and condensation of alkoxy silane using CTAB surfactant as a template. Later, cobalt salt was embedded inside the pores of the mesoporous silica by chemical impregnation method followed by reduction using NaBH4 to form Co-B nanoparticles.  It was observed that Co-B nanoparticles act as highly active catalytic centers to produce significantly higher rate (about 6 times) of H2 by hydrolysis of AB than the same amount of the corresponding Co-B powders (produced by similar chemical reduction method but without mesoporous silica support). Almost complete conversion (95%) of AB was obtained during hydrolysis, as confirmed by 11B NMR, by using nano-catalyst at room temperature. The nano-catalyst were characterized by TEM, SEM, AFM, XPS, EDS, XRD and BET surface area measurement to understand the enhanced activity of the catalyst. Availability of a large number of under-coordinated Co active atoms owing to the size and shape of nanoparticles, better dispersion & polycrystalline nature of nanoparticles, and optimum interaction with reactant provided by electron enrichment on Co sites from B, are the main features acquired by the Co-B nanoparticles that exhibit high catalytic efficiency. The efficient nature of Co-B nanoparticles is well supported by the very low activation energy and high H2 generation rate obtained from the hydrolysis of AB.

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See more of this Session: Renewable Hydrogen Production II
See more of this Group/Topical: International Congress on Energy 2011