Quantum effects in the sorption of hydrogen by mesoporous materials
| Autor: | V. B. Esel'son, Alexander V. Dolbin, N. A. Vinnikov, M. V. Khlistyuck, V. G. Gavrilko, R. M. Basnukaeva |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Surface diffusion
Materials science Physics and Astronomy (miscellaneous) Hydrogen Diffusion General Physics and Astronomy chemistry.chemical_element Sorption 02 engineering and technology Activation energy 021001 nanoscience & nanotechnology 01 natural sciences chemistry Chemical engineering Desorption 0103 physical sciences Monolayer 010306 general physics 0210 nano-technology Mesoporous material |
| Zdroj: | Low Temperature Physics. 42:1139-1143 |
| ISSN: | 1090-6517 1063-777X |
| DOI: | 10.1063/1.4973468 |
| Popis: | The sorption and desorption of hydrogen by mesoporous MCM-41 silicate material is studied at temperatures ranging from 6.8 to 290 K. It is found that a thermally activated mechanism with an estimated activation energy Ea ≈ 466 K predominates in the H2 sorption kinetics of an MCM-41 sample for temperatures of 60–290 K. For temperatures of 17–60 K the diffusion coefficient of H2 molecules in MCM-41 is almost entirely temperature independent, which is typical when a tunneling diffusion mechanism predominates over the thermally activated mechanism. Within the 8–17 K range, a change in the mobility of H2 molecules in the channels of MCM-41 is observed that appears to correspond to the formation of a monolayer (or its destruction during heating) and subsequent layers of hydrogen which have condensed on the inner surfaces of the channels. This process has an activation energy Em ≈ 21.2 K. At temperatures below 8 K the diffusion coefficients of H2 depend weakly on temperature. This presumably corresponds to a cha... |
| Databáze: | OpenAIRE |
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