Hydrogen storage performance in palladium-doped graphene/carbon composites

In this study a two-dimensional graphene sheet (GS) doped with palladium (Pd) nanoparticles was physically mixed with a superactivated carbon (AC) receptor and used as a hydrogen adsorbent. The hydrogen adsorption/desorption isotherm of the Pd-doped GS catalyst/AC composite (Pd-GS/AC) is determined using a static volumetric measurement at room temperature (RT) and pressure up to 8 MPa. The experiments show that the H2 uptake capacity of 0.82wt.% for Pd-GS/AC is obviously enhanced, measuring 49% more than the 0.55wt.% for Pd-free GS/AC at RT and 8 MPa. Highly reversible behavior of Pd-GS/AC is also observed. Moreover, the isosteric heat of adsorption for Pd-GS/AC (−14 to −10 kJ/mol) is higher than that for pristine AC (−8 kJ/mol). An increase in H2 uptake in the Pd-GS/AC suggests the occurrence of a relatively strong interaction between the spilt-over H and the receptor sites due to the spillover effect.

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► Hydrogen uptake performance of Pd-doped graphene/carbon (Pd-GS/AC) composite was investigated.
► Hydrogen uptake capacity of Pd-GS/AC composite was enhanced as 49% more than that of Pd-free GS/AC.
► Highly reversible behavior of Pd-GS/AC was obtained under ambient temperature.