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Beryllium (Be)-decorated graphene with 585 double carbon vacancy defect and nitrogen-doped porphyrin defect are investigated for hydrogen storage applications using the first principle calculation based on density functional theory. It is found that the Be atom disperses well in the defective sites of graphene and prevents clustering. For the case of Be-decorated 585 double vacancy graphene, only two H2 molecules are adsorbed via Kubas interaction with the stretched H–H bond length of 0.8 Å. In Be-decorated porphyrin defect graphene system, four H2 molecules are molecularly chemisorbed with the H–H bond length of 0.77 Å. The chemisorptions are due to the hybridization between Be-p orbital and the H-[Formula: see text] orbital. The average binding energy of H2 molecule is found to be 0.43[Formula: see text]eV/H2 which lies within the required range that can permit recycling of H2 molecules under ambient conditions.

Graphene is the thinnest 2-D material which can be regarded as a single layer of graphite. The unique electrical, mechanical and optical properties of graphene can be used in many technological applications. 2-D nanomaterials with semiconducting properties are of great interest since they can be applied in electronics industry. Pure graphene is a zerogap semiconductor or semimetal, since the electron states just cross the Fermi energy. However, the electronic properties of graphene can be tuned by doping boron or nitrogen atoms. Understanding the electronic properties in terms of density of states and band structure of doped graphene is of great relevance today. In our work, we have analyzed the electronic properties of boron and nitrogen doped graphene using Density Functional Theory (DFT). The stability and charge analysis of doped structures have been studied. The Local Density Approximation (LDA) calculations have been used to find the total energies of the structures. In addition to the electronics industry, doped graphene also has great potential to adsorb gas molecules. Therefore, we have analyzed the H2 molecule adsorption in pure, B-doped and N-doped graphene.