The hydrogen storage properties of the 2D carbon allotrope Irida-graphene (IG) were investigated using first-principles calculation. The intrinsic IG adsorption energy for H₂ is only −0.06 eV, significantly lower than the effective adsorption threshold. To improve its hydrogen storage capabilities, IG was doped with boron (B) and modified with sodium (Na). It was found that both 2Na@IG and 2Na@BIG systems could adsorb 8 pairs of H₂. However, the average adsorption energy of H₂ in the 2Na@BIG system (−0.145 eV) is higher compared to that in the 2Na@IG system (−0.134 eV), and the adsorption capacity (14.6 wt%) was superior to that of the 2Na@IG system (14.5 wt%). The introduction of B created an electron-deficient structure (BIG), enhancing electron transfer between Na and the substrate to improve Na binding energy. This enhancement resulted in stronger polarization and orbital hybridization of H₂ within the 2Na@BIG system compared to the 2Na@IG system, further boosting its adsorption performance. The charge transfer between Na and the substrate generated an electric field that polarized H₂ adsorbed around Na, while the electric field generated by the already polarized H₂ further polarizes the H₂ adsorbed in the outer layer. Density of states (DOS) diagrams illustrated orbital hybridization of the H₂ in both systems. Molecular dynamics simulations conducted at room temperature (300 K) demonstrated that the 2Na@BIG system achieved a hydrogen storage capacity of 8.8 wt.%. In conclusion, both 2Na@IG and 2Na@BIG systems exhibit potential as H₂ storage materials, but the 2Na@BIG system displays superior hydrogen storage performance compared to the 2Na@IG system.

中文翻译：

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Irida-石墨烯储氢特性的第一性原理研究


使用第一性原理计算研究了 2D 碳同素异形体 Irida-graphene （IG） 的储氢特性。H₂ 的本征 IG 吸附能仅为 −0.06 eV，明显低于有效吸附阈值。为了提高其储氢能力，IG 掺杂了硼 （B） 并用钠 （Na） 进行了改性。结果发现 2Na@IG 和 2Na@BIG 系统都可以吸附 8 对 H₂。然而，H₂ 在 2Na@BIG 体系中的平均吸附能 （-0.145 eV） 高于 2Na@IG 体系 （-0.134 eV），吸附容量 （14.6 wt%） 优于 2Na@IG 体系 （14.5 wt%）。B 的引入产生了一个缺电子结构 （BIG），增强了 Na 和衬底之间的电子转移，从而提高了 Na 结合能。与 2Na@IG 系统相比，这种增强导致 H₂ 在 2Na@BIG 系统内的极化和轨道杂化更强，进一步提高了其吸附性能。Na 和衬底之间的电荷转移产生了一个电场，使 H₂ 吸附在 Na 周围，而已经极化的 H₂ 产生的电场进一步极化了吸附在外层的 H₂。状态密度 （DOS） 图说明了 H₂ 在两个系统中的轨道杂交。在室温 （300 K） 下进行的分子动力学模拟表明，2Na@BIG 系统实现了 8.8 wt.% 的储氢容量。 总之，2Na@IG 和 2Na@BIG 系统都表现出作为 H₂ 储存材料的潜力，但与 2Na@IG 系统相比，2Na@BIG 系统表现出卓越的储氢性能。