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Small Angle Neutron Scattering (SANS) is a useful technique to investigate nanoscopic structures. In situ measurements of hydrogen absorption and desorption in complex hydrides confirmed that there is no change in their nanostructure. However, an increase and decrease in the number of scattered neutrons was observed during the absorption and desorption of hydrogen respectively. After replacing hydrogen with deuterium, a similar but much more pronounced trend was observed [1].
In this work, scattering patterns were computed from simulated structures and the corresponding integral detector signal was calculated. The diffusion of hydrogen was simulated using different models: first, assuming isotropic spherical grains led to a neutron signal was was clearly incompatible with the experimental data during absorption and desorption. To solve this problem, a second model was tested where the microstructure of the material was generated probabilistically. After removing the finite size effect using a previously introduced method [2], the calculation matched the general trends of the neutron count rate as function of hydrogen absorption and desorption in the material. These insights obtained from the microstructures can be used to engineer hydrogen storage in future.
[1] N. Aslan et al., doi: http://dx.doi.org/10.3233/JNR-190116
[2] A. Majumdar et al., doi: https://doi.org/10.3390/ijms25031547
