碳纳米管超晶格结构吸附Fe原子的电子机理

Electronic mechanism of Fe atom adsorbing for CNT supperlattice structure

为了提高碳纳米管与Fe基体之间的润湿性,构造出N掺杂有限长碳纳米管超晶格结构.第一性原理能量计算结果表明,新型超晶格结构的埋置能正向升高,结构稳定性降低,但可以显著提高外壁对Fe原子的吸附能力.差分电荷密度结果表明,掺杂体系中N原子与邻近C原子间的π键出现了畸变,使得N原子易与Fe原子发生结合.布居数和电荷转移情况表明,N原子的掺入导致Fe原子失电子能力降低,但Fe—N间共价键强度提高.超晶格结构在一定的扭转和剪切变形下仍能保持对Fe原子的吸附能力.

In order to improve the wettability between carbon nanotube （CNT） and Fe substrate, a N-doped CNT supperlattice structure with finite length was constructed. The energy calculation results based on the first principle show that the embedding energy of novel superlattice structure positively increases, the structure stability decreases, but the Fe atom adsorbing ability of outside wall gets significantly improved. The difference charge density indicates that in the doping system, the π bond connecting N atom and neighboring C atom has distorted, which allows N atom to bond with Fe atom easily. Both population and charge transfer situation show that the electron loss ability of Fe atom decreases due to the doping of N atom, but the intensity of Fe--N covalent bond increases. The superlattice structure can hold the ability to adsorb Fe atom under some extent of torsional and shear deformation.