High surface area niobium oxides as catalysts for improved hydrogen sorption properties of ball milled MgH2

We report, high surface area (up to 200 m2/g) nanocrystalline niobium oxide (so called p-Nb2O5) synthesized by 'chimie douce' route and its importance in enhancing the hydrogen sorption properties of MgH2. p-Nb2O5 induces faster kinetics than commonly used commercial Nb2O5 (c-Nb2O5) when b...

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Bibliographic Details
Published in:Journal of alloys and compounds 2008-07, Vol.460 (1-2), p.507-512
Main Authors: BHAT, V. V, ROUGIER, A, AYMARD, L, NAZRI, G. A, TARASCON, J.-M
Format: Article
Language:English
Subjects:
Alternative fuels. Production and utilization
Applied sciences
Energy
Exact sciences and technology
Fuels
Hydrogen
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Summary:We report, high surface area (up to 200 m2/g) nanocrystalline niobium oxide (so called p-Nb2O5) synthesized by 'chimie douce' route and its importance in enhancing the hydrogen sorption properties of MgH2. p-Nb2O5 induces faster kinetics than commonly used commercial Nb2O5 (c-Nb2O5) when ball milled with MgH2 (named (MgH2)catalyst) by reducing the time of desorption from 35 min in (MgH2 )c-Nb2O5 to 12 min in (MgH2 )p-Nb2O5 at 300 deg C. The BET surface area of as-prepared Nb2O5 was tuned by heat treatment and its effect on sorption properties was studied. Among them, both p-Nb2O5 and Nb2O5:350 (p-Nb2O5 heated to 350 deg C with a BET specific surface area of 46 m2/g) desorb 5 wt.% within 12 min, exhibiting the best catalytic activity. Furthermore, thanks to the addition of high surface area Nb2O5, the desorption temperature was successfully lowered down to 200 deg C, with a significant amount of desorbed hydrogen (4.5 wt.%). In contrast, the composite (MgH2 )c-Nb2O5 shows no desorption at this 'low'temperature.
ISSN:0925-8388
1873-4669
DOI:10.1016/j.jallcom.2007.05.084