H2 absorption at ambient conditions by anodized aluminum oxide (AAO) pattern-transferred Pd nanotubes occluded by Mg nanoparticles

The anodized alumina oxide (AAO) pattern-transferred Pd nanotubes occluded by Mg nanoparticles were easily manufactured by the use of vacuum evaporation technique at room temperature. The nanostructures were subjected to the H₂ absorption at ambient conditions. The material can absorb H₂ very fast (the equilibration between the hydrogen gas and within the material at each target pressure occurs in a time shorter than 110 s) reaching approximately 1 wt.% of H₂ at only 0.4 kPa of H₂ pressure. At 100 kPa the system absorbs up to 2 wt.% of H₂ at room temperature. After hydrogenation a drastic change in the structure and morphology of the nanostructures, as an effect of the metal lattice expansion in all three dimensions, was observed which was characterized by the appearance of a regular array of columns with a substantial increase in volume as compared to the nanostructures before hydrogenation. The application of the system in a potential hydrogen sensing device is envisaged.