Putungan Darwin Barayang, Lin Shi-Hsin, Wei Ching-Ming, Kuo Jer-Lai
Department of Physics, National Taiwan University, Taipei, Taiwan.
Phys Chem Chem Phys. 2015 May 7;17(17):11367-74. doi: 10.1039/c5cp00977d.
Utilizing ab initio random structure searching, we investigated Li adsorption on MoS2 and hydrogen molecules on Li-decorated MoS2. In contrast to graphene, Li can be adsorbed on both sides of MoS2, with even stronger binding than on the single side. We found that high coverages of Li can be attained without Li clustering, which is essential for hydrogen storage and Li ion batteries. Moreover, regarding battery applications, Li diffusion was also found to be easy. The fully-lithiated MoS2 can then adsorb H2 with 4.4 wt%. Interestingly, our calculations revealed that hydrogen molecules can be dissociated at high Li coverage with a minimal energy barrier. We further showed that the dissociated hydrogen atom can readily diffuse on the surface, thus keeping the reaction site active. We therefore propose that Li-MoS2 could be an inexpensive alternative catalyst to noble metals in hydrogen dissociation reactions.
利用从头算随机结构搜索方法，我们研究了锂在二硫化钼（MoS₂）上的吸附以及氢分子在锂修饰的二硫化钼上的吸附情况。与石墨烯不同，锂可以吸附在二硫化钼的两侧，且其结合力比单面吸附更强。我们发现，在不发生锂团聚的情况下可以实现锂的高覆盖率，这对于储氢和锂离子电池来说至关重要。此外，就电池应用而言，还发现锂的扩散很容易。完全锂化的二硫化钼随后能够以4.4 wt%的比例吸附氢气。有趣的是，我们的计算表明，在高锂覆盖率下，氢分子能够以最小的能垒发生解离。我们进一步表明，解离后的氢原子能够在表面上轻松扩散，从而使反应位点保持活性。因此，我们提出锂 - 二硫化钼在氢解离反应中可能是一种比贵金属更廉价的替代催化剂。
