Park Hong-Lae, Yoo Dong Su, Yi Sung-Chul, Chung Yong-Chae
Department of Materials Science and Engineering, Hanyang University, Seoul 133-791, Republic of Korea.
J Nanosci Nanotechnol. 2011 Jul;11(7):6131-5. doi: 10.1166/jnn.2011.4503.
Based on first-principles plane wave calculations, it was shown that boron substituted graphene with Ti metal atom adsorption can be used as a high capacity hydrogen storage material. Boron substitution in graphene enhances the Ti metal adsorption energy, which is much larger than that in the case of pure graphene, and than the Ti cohesive energy. The Ti metal atom can be well dispersed on boron-substituted graphene and can form a 2 x 2 pattern because the clustering of the Ti atoms is hindered by the repulsive Coulomb interaction between them. The H2 adsorption behavior on Ti metal atoms was investigated, along with the H2 bonding characteristics and the open-metal states of Ti. It was found that one Ti adatom dispersed on the double sides of graphene can absorb up to eight H2 molecules, corresponding to a 7.9% hydrogen storage capacity. In addition, the adsorption behaviors of non-H2 atoms like C and B were calculated to determine if Ti atoms can remain in an open-metal state in boron-substituted graphene.
基于第一性原理平面波计算结果表明，吸附钛金属原子的硼取代石墨烯可作为一种高容量储氢材料。石墨烯中的硼取代增强了钛金属的吸附能，该吸附能远大于纯石墨烯情况下的吸附能，也大于钛的内聚能。由于钛原子之间的库仑排斥相互作用阻碍了它们的聚集，钛金属原子能够很好地分散在硼取代的石墨烯上，并能形成2×2的图案。研究了氢分子在钛金属原子上的吸附行为，以及氢分子的键合特性和钛的开放金属态。结果发现，分散在石墨烯两侧的单个钛吸附原子最多可吸收八个氢分子，储氢容量达7.9%。此外，还计算了碳和硼等非氢原子的吸附行为，以确定钛原子在硼取代石墨烯中是否能保持开放金属态。
