Fe-Al core-shell structure as an efficient catalyst for dual hydrogen production and storage by thermochemical water splitting: A reactive molecular dynamic simulation

Abstract

Catalysts with dual functions in hydrogen production and storage are desired for the low-cost technology. In the preceding view, we used reactive force molecular dynamics to demonstrate how effective the Fe-Al core-shell structure is at breaking up water molecules and storing hydrogen free radicals via thermochemical water splitting. The results show that at T similar to 600 K, water molecules begin to dissociate in the presence of a Fe-Al catalyst, releasing OH and H free radicals. It is worth noting that the produced OH free radicals are bonded to the Al-shell, whereas the H free radicals move to the Fe-core and store via a chemical bond. Interestingly, at T < 1200 K, there is no Fe-O bond. This could be due to Al having a higher oxidation potential than Fe, causing OH free radicals to preferentially associate with the Al-shell. Furthermore, at 2000K < T > 3000 K, the number of Fe -H bonds decreases while the number of H-H bonds increases, indicating that the stored H atom desorbs and forms an H2 molecule. Temperature can thus be used to monitor the ability of Fe-Al catalysts to dissociate water, store hydrogen, and produce hydrogen. This research shows that developing core-shell-type catalysts can provide an effective solution for hydrogen generation, storage, and transportation. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.