B12Sc4和B12Ti4团簇的储氢性质

提出了两个稳定的团簇B₁₂Sc₄和B₁₂Ti₄, 基于理论计算, 研究了它们的结构与储氢性质. 结果发现, 在这两个稳定的团簇中, 过渡金属原子不会聚合在一起而影响它们对氢气的吸附. B₁₂Sc₄最多可以吸附12个氢分子, 达到7.25% (质量分数)的储氢量. 它的平均每氢分子吸附能量为10.5 kJ·mol^-1. B₁₂Ti₄最多只能吸附8个氢分子, 储氢量为4.78%. 但平均每氢分子吸附能量可达50.2 kJ·mol^-1. 进一步计算表明, 即使在77 K,也需要很高的氢气压力才能使12个氢分子都吸附到B₁₂Sc₄上. 电子结构分析表明, B₁₂Ti₄-nH₂吸附结构中的Kubas作用要大于相应B₁₂Sc₄-nH₂结构中的Kubas作用.

Hydrogen Storage Properties of B12Sc4 and B12Ti4 Clusters

The structures and hydrogen storage properties of two stable B₁₂Sc₄ and B₁₂Ti₄ clusters have been investigated using ab initio calculations. No metal atom clustering occurs in the clusters. The B₁₂Sc₄ hosts 12 H₂ to achieve 7.25% (mass fraction) hydrogen storage capacity with an average binding energy (ABE) of -10.4 kJ·mol^-1 per H₂, while the B₁₂Ti₄ can only host 8 H₂ (4.78%, mass fraction) with a higher ABE (-50.2 kJ·mol^-1 per H₂). High hydrogen pressure is needed for B₁₂Sc₄ to hold 12 H₂, even at 77 K. Electronic structure analysis indicates that the Kubas interaction in the B₁₂Ti₄-nH₂ complex is much stronger than that in the B₁₂Sc₄-nH₂ complex.