Li修饰的C_6分子对H_2O的吸附研究

Adsorption of H_2O by the Li decorated C_6Li molecule

采用密度泛函理论中的广义梯度近似研究C6Li吸附H2O分子并将之进行分解的催化过程.几何优化发现:Li原子最稳定的吸附位置是位于C原子顶位上方.研究表明,第一个H2O分子吸附在C6Li上需要克服1.77 eV的能量势垒,然后分解为H和OH且与Li原子成键.当吸附第二个H2O分子时,第二个H2O分子需要克服1.2 eV的能量势垒分解为H和OH,其中H与Li原子上的H原子结合成H2,OH则替代Li原子上的H结合在Li原子上.因此C6Li可以作为催化剂将H2O分子进行分解得到H2.分析可知:C6Li主要是通过Li原子与H2O之间形成的偶极矩作用来吸附H2O分子,与C60Li12的储氢机制类似.研究结果可为储氢材料的制备提供一个新的思路.

The generalized gradient approximation based on the density functional theory is used to study the adsorption process of H2O molecules by the Li decorated C6Li and the catalytic process of decomposition of H2O molecules. The geometry optimization shows that the most stable adsorption position of the Li is above the C atom of C6. Research shows that the adsorption of the first H2O molecule on C6Li needs to overcome an energy barrier of 1.77 eV, then H2O is decomposed into H and OH and bonding with Li atoms. Furthermore, the adsorption of the second H2O molecule needs to overcome an energy barrier of 1.2 eV and then the H2O molecule is decomposed into H and OH, the H atom in which and the H atom on the Li atom combine into an H2molecule. OH replacing H atoms on Li atoms combines with the Li atom. Therefore, C6Li can be used as a catalyst for H2O molecules, and thus provide a new train of thought for the preparation of hydrogen storage material. The analysis shows that C6Li mainly adsorbs the H2O molecules through the dipole moment formed by the positive charge of Li and negative charge of H2O.