| Graphyne, a novel allotropic form of carbon, was predicted to have a high possibility of synthesis. Graphyne is a carbon sheet with three different types of carbon atoms of sp and sp2hybridized nature. Due to the special structural properties, graphyne has a great application prospect in the field of hydrogen storage. In this study, we use first-principle approaches to investigate the structural and electronic properties of metal-adsorbed and light element-doped graphyne. The main research findings are summarized as follows:1. Based on first-principle calculations, we study the structural and electronic properties of Ti-decorated graphyne. By calculating binding energy, we find that Ti atom adsorbed on Hlsite (the hollow site of12-C hexagonal) is more stable. To illustrate why Hlsite is the most stable adsorption site, we further analysize the electronic properties. We apply different intensity of electric field (0.000-0.014a.u.) to investigate the effect of electric field on Ti-decorated graphyne for hydrogen storage. It can be revealed that as electric field increases, the adsorption energy and the bond length of H-H increases.2. Hydrogen adsorption on B/N-doped graphyne under different external electric fields is investigated by first-principles calculations. Through the analyses of structural properties of B/N-doped graphyne, we find that NbBf, BbNo, BaNe and NaBg are more likely to synthesize. Through molecular dynamics calculation, it is found that the structures for B/N doped graphyne are stable. For NbBf, BbNo, BaNe and NaBg, the most stable positions for hydrogen adsorption are H1sites. For a single H2adsorbed on B/N-doped graphyne, the adsorption energy increases greatly with the electric field increases, and the maximum adsorption energy is0.47eV when the electric field is0.038a.u. It is also found that the adsorption energy of H2adsorbed on NbBf under electric field increases faster than H2adsorbed on BhNo, BaNe and NaBg. |
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