Mn掺杂单空位缺陷碳纳米管吸附NH3分子的第一性原理研究

Adsorption of NH3 on Mn-Doped Carbon Nanotubes with a Single-Vacancy Defect:A First Principles Study

研究本征碳纳米管、单空位缺陷碳纳米管、Mn掺杂碳纳米管和Mn掺杂单空位缺陷碳纳米管对NH3分子的吸附效果。采用基于密度泛函理论的第一性原理方法,对各个模型的吸附能、吸附距离、电荷转移量、电子密度等的分析后发现:单空位缺陷有利于提高碳纳米管对NH3分子的吸附效果,但碳纳米管未能与NH3分子形成化学吸附;掺杂Mn原子能大大提高单空位缺陷碳纳米管与NH3间的吸附能和电荷转移量,同时减小其吸附距离,说明Mn原子掺杂的单空位缺陷碳纳米管能够对NH3分子产生化学吸附。Mn原子掺杂单空位缺陷碳纳米管作为NH3气敏材料值得后续深入研究。

Adsorption of NH3 molecules on the carbon nanotubes(CNTs),including the CNTs with and without a single-vacancy defect and/or doped Mn-atom,was investigated in the first-principles method based on density functional theory.The adsorption energy,adsorption distance,charge-transfer and electron density were analyzed.The calculated results show that the single-vacancy defect and Mn-doping has a major impact.For instance,a single-vacancy defect slightly increases the adsorption of NH3,though fails to induce chemical adsorption with CNTs;the doped Mn-atom significantly shortens the adsorption distance,considerably increases the adsorption energy and charge transfer,and possibly promotes a stable chemical adsorption between NH3 and CNTs with a single-vacancy defect.We suggest that the Mn-doped CNTs with a single-vacancy defect may be of some basic and technological interest in synthesis of advanced NH3-gas sensitive material.