Theoretical study of H2 adsorption on metal-doped graphene sheets with nitrogen-substituted defects

•The N-edged defects in graphene can achieve metal doping.•The strong hybridization and electrostatic interactions are contribute to the metals and H2 adsorption.•The synergistic effect of Ca and the adsorbed H2 influences the multiple H2 adsorptions.•We recommend Ca-doped N-substituted pyrrolic graphene is proposed to a promising candidate for H2 storage.

In the present work, we perform a theoretical study of light metal (Li, Na, and Ca) doping and H2 adsorption on graphene sheets with N-substituted defects. Through density functional theory calculations, the adsorption energies, density of states, and extent of charge transfer in systems featuring H2 adsorption on metal-doped species (ideal, pyridinic, and pyrrolic graphene sheets) are obtained, and we determine that both N and metal atoms play important roles in H2 adsorption. In addition, molecular dynamics simulations are employed to evaluate the nature of H2 adsorption at room temperature. All computational results indicated that Ca-doped pyrrolic graphene could be expected as a promising candidate for H2 storage.

Graphical abstractLight metals (Li, Na, and Ca) doping and H2 adsorption on graphene sheets with N-substituted defects are studied through density functional theory calculations, and we found that both N and metal atoms play important roles in H2 adsorption properties. Additional, the performance of H2 adsorption at room temperature have been evaluated by using molecular dynamics simulations. All data demonstrated that Ca-doped pyrrolic graphene could be a promising candidate for H2 storage.Figure optionsDownload full-size imageDownload as PowerPoint slide