Hydrogen and noble gas interactions with iron nano-flakes

Exposure of pure iron nano-flakes to hydrogen generates a high heat evolution associated with hydrogen uptakes shown by flow-through microcalorimetry. A large part of the hydrogen was found to be irreversibly absorbed by the iron flakes at 220 8C and atmospheric pressure, but an increased desorption of hydrogen was achieved by noble gases, such as helium and argon. Thus the iron surfaces displayed strong affinity for hydrogen, but also, surprisingly, for the noble gases, which were found to be able to displace hydrogen from the iron surfaces. The uptake of hydrogen by the iron flakes was observed to reach 9 wt.% after exposure for 5 h, which may be of interest in hydrogen storage applications. Desorption with the help of argon may provide an acceptable method of hydrogen recovery.