Hydrogen adsorption behavior of graphene above critical temperature

We evaluate the hydrogen adsorption behavior of the pristine single-layer graphene sheets in a powder form, which was performed at cryogenic and room temperatures. Only 0.4 wt.% and <0.2 wt.% hydrogen uptake was obtained at 77 K under 100 kPa and room temperature under 6 MPa, respectively, for the pristine graphene sample with a BET specific surface area of 156 m2 g−1. Structure/property investigations suggest that the low specific surface area and weak binding to hydrogen should be responsible for the small gravimetric uptake of pristine graphene sample.