Morphology‐Dependent Stability of Complex Metal Hydrides and Their Intermediates Using First‐Principles Calculations
| Autor: | Mark D. Allendorf, ShinYoung Kang, Tae Wook Heo, Brandon C. Wood |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Kinetics 02 engineering and technology Reaction intermediate 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Atomic and Molecular Physics and Optics 0104 chemical sciences Metal Hydrogen storage Chemical physics visual_art Metastability Phase (matter) visual_art.visual_art_medium Molecule Physical and Theoretical Chemistry Complex metal hydride 0210 nano-technology |
| Zdroj: | ChemPhysChem. 20:1340-1347 |
| ISSN: | 1439-7641 1439-4235 |
| Popis: | Complex light metal hydrides are promising candidates for efficient, compact solid-state hydrogen storage. (De)hydrogenation of these materials often proceeds via multiple reaction intermediates, the energetics of which determine reversibility and kinetics. At the solid-state reaction front, molecular-level chemistry eventually drives the formation of bulk product phases. Therefore, a better understanding of realistic (de)hydrogenation behavior requires considering possible reaction products along all stages of morphological evolution, from molecular to bulk crystalline. Here, we use first-principles calculations to explore the interplay between intermediate morphology and reaction pathways. Employing representative complex metal hydride systems, we investigate the relative energetics of three distinct morphological stages that can be expressed by intermediates during solid-state reactions: i) dispersed molecules; ii) clustered molecular chains; and iii) condensed-phase crystals. Our results verify that the effective reaction energy landscape strongly depends on the morphological features and associated chemical environment, offering a possible explanation for observed discrepancies between X-ray diffraction and nuclear magnetic resonance measurements. Our theoretical understanding also provides physical and chemical insight into phase nucleation kinetics upon (de)hydrogenation of complex metal hydrides. |
| Databáze: | OpenAIRE |
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