Hydrogen functionalization on graphene has attracted tremendous research interest for optimized characteristics of nanodevices. Systematic molecular dynamics simulations have been performed to investigate the mechanical properties of hydrogen functionalized graphene and related allotropes. The effect of the degree of functionalization and hydrogen arrangement on the mechanical properties and failure process are investigated. For graphene materials with hydrogen atoms randomly arranged on the surface, the intrinsic strength deteriorate drastically with increasing H-coverage within the sensitive threshold, beyond which the mechanical properties remain insensitive to the increase in H-coverage. This drastic deterioration arises both from the conversion of sp2 to sp3 bonding and easy rotation of unsupported sp3 bonds. Compared to random hydrogenation, the interface of sp2 and sp3 bonds provided by mosaic-like hydrogen pattern retards the deterioration of intrinsic strength caused by hydrogenation. We also consider the mechanical properties of defective graphene structures, the results show that patterned hydrogenation surrounding the void edge will decrease edge stress. The shielding effect of hydrogenation on stress concentration provides noticeable amelioration of failure strength, which is sensitive to the defect structures because of the difference in stress concentration. Our results suggest that the unique coverage-dependent deterioration of the mechanical properties is tunable by manipulating the arrangement of hydrogen atoms. Hydrogenation can be fully used for optimized characteristics of graphene materials based nanodevices.

Hydrogen functionalization on graphene has attracted tremendous research interest for optimized characteristics of nanodevices. Systematic molecular dynamics simulations have been performed to investigate the mechanical properties of hydrogen functionalized graphene and related allotropes. The effect of the degree of functionalization and hydrogen arrangement on the mechanical properties and failure process are investigated. For graphene materials with hydrogen atoms randomly arranged on the surface, the intrinsic strength deteriorate drastically with increasing H-coverage within the sensitive threshold, beyond which the mechanical properties remain insensitive to the increase in H-coverage. This drastic deterioration arises both from the conversion of sp2 to sp3 bonding and easy rotation of unsupported sp3 bonds. Compared to random hydrogenation, the interface of sp2 and sp3 bonds provided by mosaic-like hydrogen pattern retards the deterioration of intrinsic strength caused by hydrogenation. We also consider the mechanical properties of defective graphene structures, the results show that patterned hydrogenation surrounding the void edge will decrease edge stress. The shielding effect of hydrogenation on stress concentration provides noticeable amelioration of failure strength, which is sensitive to the defect structures because of the difference in stress concentration. Our results suggest that the unique coverage-dependent deterioration of the mechanical properties is tunable by manipulating the arrangement of hydrogen atoms. Hydrogenation can be fully used for optimized characteristics of graphene materials based nanodevices.