Migration and desorption of hydrogen atom and molecule on/from graphene

Migration and desorption of hydrogen atom and molecule on/from graphene are crucial for understanding mechanism of the hydrogen storage in graphene and graphene synthesis. All possible hydrogen atom migration, hydrogen atom and hydrogen molecule desorption from single layer graphene have been studied systematically by using functional density theory B3LYP/6-31G(d). Our results show that the hydrogen atom desorption is energetically favorable with the lowest desorption barrier of 149.3 kJ mol−1 from stable hydrogen adsorption sites, while the migration is restricted due to high barriers which are greater than 191.0 kJ mol−1. Hydrogen molecular desorption is possible only from edge adsorbed hydrogen atom due to its comparable barrier of 149.9 kJ mol−1. Other hydrogen molecular desorption pathways are less likely due to small population of the reaction species.

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