Is hydrogen diffusion in amorphous metals non-Arrhenian

ABSTR A C T Hydrogen diffusion is critical to the performance of metals for hydrogen storage as well as other important applications. As compared to its crystalline counterpart which follows the Arrhenius relation, hydrogen diffusion in amorphous metals sometimes are experimen-tally found to be non-Arrhenian. In this work we studied the diffusion of hydrogen in amorphous Pd-H and Zr-Cu-H alloys based on molecular dynamics simulations. Our simulations confirm Arrhenian diffusion behaviour for hydrogen in amorphous alloys, in contrast to previous computational studies which predict non-Arrhenian behaviour. We show that the simulated non-Arrhenian diffusion based on molecular dynamics could result from a systematic error related to too short simulation time. We also discussed the experimental non-Arrhenian behaviour of hydrogen diffusion within the framework of quantum tunneling and amorphous-amorphous phase transformations. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

In this study, hydrogen diffusion in amorphous Pd-H and Zr-Cu-H alloys was investigated using molecular dynamics simulations. Our simulations revealed that hydrogen diffusion in the amorphous alloys follows Arrhenius behavior, contrary to previous computational studies predicting non-Arrhenius behavior. We demonstrated that the simulated non-Arrhenius diffusion may be attributed to a systematic error caused by insufficient simulation time. Additionally, we discussed the experimental non-Arrhenius behavior of hydrogen diffusion within the context of quantum tunneling and amorphous-amorphous phase transformations.