Mg原子修饰的封闭型六硼烷B_6H_6^(2-)储氢性质的研究

Hydrogen storage of Mg-decorated closo-hexaborate B_6H_6^(2-)

利用密度泛函理论的方法研究了Mg原子修饰的封闭型六硼烷B6H26吸附氢的性能.Mg可以稳定地结合在B6H2-6上,它可以吸附六个氢分子.电荷转移所导致的Mg周围电场的增强和体系更大的偶极矩使得MgB6H2-6比MgB6H6具有更好的储氢性能,储氢密度达到11.1 wt%,氢分子的平均结合能在0.23 eV/H2至0.34 eV/H2之间.结果表明可以通过控制金属-有机物体系的电荷态来增强电场,进而改善其储氢性能.

Hydrogen storage capacity of Mg-decorated closo-hexaborate B6H2- has been studied using density functional theory. The binding strength of Mg atom is sufficiently large to ensure the stability of MgB6H2-. Each Mg atom can adsorb six H2 molecules. Moreover, the larger dipole moment combined with enhanced electrostatic field around the Mg atom originates from the charge transfer from B6H2- to Mg, accounting for the higher adsorption capacity of MgB6H62- than that of MgB6H6. Hydrogen storage capacity of MgB6H2- can be up to 11.1 wt% with an average binding energy between 0.23 eV and 0.34 eV. The electrostatic field around the Mg atom can be enhanced by controlling the charge state of the metal-organic complex, thereby significantly improving the hydrogen adsorption capacity.