Hydrogen storage capacity on Ti-decorated porous graphene: First-principles investigation
Hydrogen storage capacity on Ti-decorated porous graphene: First-principles investigation
复制标题
钛装饰多孔石墨烯的储氢能力：第一性原理研究
DOI：
10.1016/j.apsusc.2017.10.231
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发表时间：
2018-03-15
影响因子：
6.7
通讯作者：
Wu, Xiaojuan
中科院分区：
文献类型：
--
作者：
Yuan, Lihua;Kang, Long;Wu, Xiaojuan
用密度泛函理论结合广义梯度近似方法研究了钛修饰的多孔石墨烯(PG)的储氢容量。讨论了钛原子在PG表面的可能吸附位置和Ti-PG体系的电子性质。结果表明，钛原子倾向于强吸附在C六边形上方的中心位置，结合能为3.65 eV，极化和杂化机制均有助于钛原子在PG上的吸附。为了避免钛原子之间的聚集趋势，PG晶胞的单边应该只包含一个钛原子。在PG的单面，四个H-2分子可以吸附在Ti原子周围，其吸附机理不仅来自于Ti和H原子之间的极化机制，而且来自于Ti原子、H-2分子和C原子之间的轨道杂化。在PG双面的情况下，钛修饰PG单元电池可以吸附8个H-2分子，平均吸附能为-0.457 eV，重量储氢量为6.11wt.%。分子动力学模拟结果表明，Ti-PG体系的晶胞两侧可以吸附6个H-2分子，且在300K和无外压条件下，Ti-PG的构型非常稳定，表明钛修饰PG在常温下可以作为一种潜在的储氢介质。(C)2017爱思唯尔B.V.保留所有权利。
Hydrogen storage capacity on Titanium (Ti) decorated porous graphene (PG) has been investigated using density functional theory simulations with generalized gradient approximation method. The possible adsorption sites of Ti atom on PG and electronic properties of Ti-PG system are also discussed. The results show a Ti atom prefers to strongly adsorb on the center site above the C hexagon with the binding energy of 3.65 eV, and the polarization and the hybridization mechanisms both contribute to the Ti atom adsorption on PG. To avoid a tendency of clustering among Ti atoms, the single side of the PG unit cell should only contain one Ti atom. For the single side of PG, four H-2 molecules can be adsorbed around Ti atom, and the adsorption mechanism of H-2 molecules come from not only the polarization mechanism between Ti and H atoms but also the orbital hybridization among Ti atom, H-2 molecules and C atoms. For the case of double sides of PG, eight H-2 molecules can be adsorbed on Ti-decorated PG unit cell with the average adsorption energy of -0.457 eV, and the gravimetric hydrogen storage capacity is 6.11 wt.%. Furthermore, ab inito molecular-dynaics simulation result shows that six H-2 molecules can be adsorbed on double sides of unit cell of Ti-PG system and the configuration of Ti-PG is very stable at 300 K and without external pressure, which indicates Ti-decorated PG could be considered as a potential hydrogen storage medium at ambient conditions. (C) 2017 Elsevier B.V. All rights reserved.