金原子掺杂的碳纳米管吸附CO气体的密度泛函理论研究

A density functional theory study of absorption behavior of CO on Au-doped single-walled carbon nanotubes

鉴于碳纳米管复合材料具有较强气敏性,该性质对于指导剧毒气体探测器的研发具有重要意义,因此,本文采用密度泛函方法对CO气体在本征、金原子掺杂(8,0)单壁碳纳米管的吸附行为进行研究.通过对吸附体系的几何、电子结构研究表明,CO分子在金原子掺杂的碳纳米管外壁的金原子位置处的吸附能力远大于CO在本征碳纳米管处的吸附,此外,还计算了两种典型位置的电子密度、态密度,进一步支持了掺金碳纳米管对CO气体具有超强的敏感性,因此,金原子掺杂的碳纳米管有望成为探测CO气体的新一代气敏元件.

The absorption behaviors of CO on the（8,0） semiconducting intrinsic and gold doped（Au-doped） single-walled carbon nanotubes（SWCNTs） are investigated by the density functional theory because superior sensitivity of carbon nanotube to many toxic gases becomes a field of growing interest.It is shown that CO molecules can be absorbed to Au atoms on the wall of Au-doped SWCNT with a bingding energy as high as 2.1eV,and can attract lager charge transfer 0.23.Compared with the intrinsic SWCNT,the Au-doped SWCNT presents a high sensitivity to CO in terms of the calculated geometrical structures and electronic properties,Furthermore,the calculated electron densities of two representative adsorption positions show that Au-doped SWCNT electron clouds overlap more on the top of carbon adsorbed CO.By comparison with the oxygen absorption on SWCNT,we infer that the molecular CO absorbed on Au-doped SWCNT can induce significant change in the conductivity of SWCNT.So Au-doped SWCNT is expected to be a potential candidate for detecting the presence of CO.