Chen Yuhong, Wang Jing, Yuan Lihua, Zhang Meiling, Zhang Cairong
State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China.
School of Science, Lanzhou University of Technology, Lanzhou 730050, China.
Materials (Basel). 2017 Aug 2;10(8):894. doi: 10.3390/ma10080894.
The generalized gradient approximation (GGA) function based on density functional theory is adopted to investigate the optimized geometrical structure, electron structure and hydrogen storage performance of Sc modified porous graphene (PG). It is found that the carbon ring center is the most stable adsorbed position for a single Sc atom on PG, and the maximum number of adsorbed H₂ molecules is four with the average adsorption energy of -0.429 eV/H₂. By adding a second Sc atom on the other side of the system, the hydrogen storage capacity of the system can be improved effectively. Two Sc atoms located on opposite sides of the PG carbon ring center hole is the most suitable hydrogen storage structure, and the hydrogen storage capacity reach a maximum 9.09 wt % at the average adsorption energy of -0.296 eV/H₂. The adsorption of H₂ molecules in the PG system is mainly attributed to orbital hybridization among H, Sc, and C atoms, and Coulomb attraction between negatively charged H₂ molecules and positively charged Sc atoms.
采用基于密度泛函理论的广义梯度近似（GGA）函数，研究了Sc修饰的多孔石墨烯（PG）的优化几何结构、电子结构和储氢性能。研究发现，对于PG上的单个Sc原子，碳环中心是最稳定的吸附位置，吸附的H₂分子最大数量为4个，平均吸附能为-0.429 eV/H₂。通过在体系的另一侧添加第二个Sc原子，可以有效提高体系的储氢容量。位于PG碳环中心孔相对两侧的两个Sc原子是最合适的储氢结构，在平均吸附能为-0.296 eV/H₂时，储氢容量达到最大值9.09 wt%。PG体系中H₂分子的吸附主要归因于H、Sc和C原子之间的轨道杂化，以及带负电的H₂分子与带正电的Sc原子之间的库仑引力。
