| DOI | Resolve DOI: https://doi.org/10.1016/j.actamat.2012.06.009 |
|---|
| Author | Search for: Tan, XueHai1; Search for: Zahiri, Beniamin; Search for: Holt, Chris M. B.1; Search for: Kubis, Alan1; Search for: Mitlin, David1 |
|---|
| Affiliation | - National Research Council of Canada. Security and Disruptive Technologies
|
|---|
| Format | Text, Article |
|---|
| Subject | Hydrogen storage; Magnesium hydride; TEM; Microstructure; Catalyst |
|---|
| Abstract | Magnesium hydride combined with a new bimetallic Nb–V catalyst displays remarkably rapid and stable low temperature (200 °C) hydrogen storage kinetics, even after 500 full volumetric absorption/desorption cycles. The system is also able to fairly rapidly absorb hydrogen at room temperature at a pressure of 1 bar. This unprecedented absorption behavior was demonstrated for 20 cycles. We employed extensive cryo-stage transmission electron microscopy (TEM) analysis on fully and partially sorbed materials to provide insight into the rapid Mg to MgH2 phase transformation. After extended cycling of what was initially a 1.5 μm thick fully dense alloy film, the sample structure becomes analogous to that of a weakly agglomerated nanocomposite powder. The cycled Mg–V–Nb structure consists of a dense distribution of catalytic Nb–V nanocrystallites covering the surfaces of larger Mg and MgH2 particles. The partially absorbed 20 °C and 200 °C microstructures both show this morphology. TEM results combined with Johnson–Mehl–Avrami-type kinetic analysis point to the surface catalyst distribution and stability against coarsening as being a key influence on the two-stage hydriding kinetics. Remarkably, the mean size of the Nb0.5V0.5H nanocrystallites stays essentially invariant throughout cycling; it is 3 nm after 45 cycles and 4 nm after 500 cycles. A mechanistic description is provided for the cycling-induced microstructural evolution in the ternary alloy as well as in the binary baselines. |
|---|
| Publication date | 2012-08-27 |
|---|
| In | |
|---|
| Language | English |
|---|
| Peer reviewed | Yes |
|---|
| Identifier | S1359645412003710 |
|---|
| NPARC number | 21268616 |
|---|
| Export citation | Export as RIS |
|---|
| Report a correction | Report a correction (opens in a new tab) |
|---|
| Record identifier | b2584010-fbe6-4fd1-834c-c0fa8f58f7ef |
|---|
| Record created | 2013-10-28 |
|---|
| Record modified | 2020-04-21 |
|---|
