| DOI | Resolve DOI: https://doi.org/10.1021/jp211254k |
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| Author | Search for: Zahiri, B.1; Search for: Danaie, M.; Search for: Tan, X.1; Search for: Amirkhiz, B.S.1; Search for: Botton, G.A.; Search for: Mitlin, D.1 |
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| Affiliation | - National Research Council of Canada. National Institute for Nanotechnology
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| Format | Text, Article |
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| Subject | Core shell; Driving forces; Hydrogen absorption; Hydrogen sorption; Hydrogen uptake; Magnesium hydride; matrix; Metal hydride systems; Nano scale; Nanoscale catalysts; Nanoscale-dispersion; Powder samples; Room temperature; TEM analysis; Transmission electron; Activation energy; Catalysts; Desorption; Hydrides; Hydrogen; Hydrogen storage; Hydrogenation; Magnesium; Nanotechnology; Transmission electron microscopy; Vanadium; Chromium |
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| Abstract | We created a bimetallic chromium vanadium hydrogen sorption catalyst for magnesium hydride (MgH 2). The catalyst allows for significant room-temperature hydrogen uptake, over 10 cycles, at absorption pressures as low as 2 bar. This is something that has never been previously achieved. The catalyst also allowed for ultrarapid and kinetically stable hydrogenation cycling (over 225 cycles) at 200 and at 300 °C. Transmission electron microscopy analysis of the postcycled samples revealed a nanoscale dispersion of Cr-V nanocrystallites within the Mg or MgH 2 matrix. TEM analysis of the partially absorbed specimens revealed that even at a high absorption pressure, that is, a high driving force, relatively few hydride nuclei are formed at the surface of the pre-existing magnesium, ruling out the presence of any contracting volume (also termed contracting envelope or core shell) type growth. HRTEM of the cycled and desorbed powder sample demonstrated that the bcc Cr-V phase is crystalline and nanoscale. We experimentally demonstrated that the activation energy for hydrogen absorption is not constant but rather evolves with the driving force. This finding sheds new insight regarding the origins of the wide discrepancy in the literature - reported values of the hydrogenation activation energy in magnesium hydride and in related metal hydride systems. © 2011 American Chemical Society. |
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| Publication date | 2012 |
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| In | |
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| Language | English |
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| Peer reviewed | Yes |
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| NPARC number | 21269438 |
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| Export citation | Export as RIS |
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| Report a correction | Report a correction (opens in a new tab) |
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| Record identifier | d49b1e06-2ede-4d85-9b90-a47a21a7e821 |
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| Record created | 2013-12-12 |
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| Record modified | 2020-04-21 |
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