Tribochemical Decomposition of Light Ionic Hydrides at Room Temperature
Roman Nevshupa1, Jose Ramón Ares2, Jose Francisco Fernández2
1†Spanish National Research Council, Institute "Eduardo Torroja" (IETCC-CSIC), C/Serrano Galvache 4, Madrid 28033, Spain.
The Journal of Physical Chemistry Letters
|August 13, 2015
Summary
Mechanical deformation triggers rapid, nonthermal decomposition of magnesium hydride (MgH2), releasing significant hydrogen. This tribochemical process enhances decomposition rates compared to slow thermal breakdown.
Area of Science:
- Materials Science
- Chemistry
- Tribology
Background:
- Magnesium hydride (MgH2) is a promising material for hydrogen storage.
- Understanding its decomposition mechanisms is crucial for practical applications.
- Tribochemical effects, induced by mechanical stress, are not fully understood for MgH2.
Purpose of the Study:
- To investigate the in situ, real-time tribochemical decomposition of MgH2 at room temperature.
- To quantify hydrogen release during mechanical deformation.
- To characterize the decomposition products and understand the underlying mechanisms.
Main Methods:
- In situ and real-time observation of MgH2 deformation on a micrometric scale.
- Hydrogen release measurement during deformation.
- Confocal-microRaman spectroscopy for analyzing decomposition products.
Main Results:
- Near-full hydrogen depletion observed in the deformed zone within 1 second.
- High instantaneous hydrogen release rates (3-50 nmol/s) indicate a nonthermal decomposition process.
- Mechanically induced structural distortion and reduced crystal size of MgH2 enhance decomposition.
Conclusions:
- Mechanical deformation is a highly effective method for rapid MgH2 decomposition.
- Tribochemical decomposition of MgH2 is significantly faster than its thermal decomposition.
- This study provides insights into MgH2 hydrogen release mechanisms under mechanical stress.
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