钴掺杂氮化硼纳米管吸附氯酚类污染物的理论研究

氯酚(CPs)类污染物是形成持久性有机污染物二噁英的先驱物, 具有较强的致畸、致癌和致突变性. 为探索去除或检测这类污染物的新型材料, 应用密度泛函理论研究了(8,0)单壁氮化硼纳米管(BNNT)和Co掺杂的(8,0)单壁氮化硼纳米管(Co-BNNT)对2-氯酚(2-CP)、2,4,6-三氯酚(TCP)、五氯酚(PCP)的吸附行为及作用机制. 结果表明, 与BNNT相比, Co-BNNT费米能级附近出现杂化态, 带隙明显减小. BNNT对2-CP、TCP和PCP呈现物理吸附, 而Co-BNNT对三种氯酚则是化学吸附, 纳米管与分子间发生了明显的电荷转移, 体系态密度在费米能级附近发生了明显变化. Co原子掺杂明显增强了BNNT的电子输运能力, 提高了纳米管对氯酚的吸附活性. Co-BNNT有望是去除或检测氯酚类污染物的潜在资源.

Theoretical Study of Adsorption of Chlorinated Phenol Pollutants on Co-Doped Boron Nitride Nanotubes

Chlorinated phenols (CPs) are the main precursors for forming the persistent organic pollutants dioxins and have strong teratogenicity, carcinogenicity, and mutagenicity. To explore the novel material for the removal or detection of these pollutants, we used density functional theory calculations to investigate the adsorption behaviors and interaction mechanisms of 2-chlorophenol (2-CP), 2,4,6-trichlorophenol (TCP), and pentachlorophenol (PCP) on pristine and Co-doped (8,0) single-walled boron nitride nanotubes (denoted by BNNT and Co-BNNT, respectively). The results show that compared with BNNT, Co-BNNT introduces local states near the Fermi levels, and has a smaller band gap. BNNT physisorbs 2-CP, TCP, and PCP molecules, whereas Co-BNNT presents chemisorption towards them. Charge-transfer between Co-BNNT and molecules can be clearly observed and the electronic densities of states of the doped systems change significantly near the Fermi levels after adsorption of molecules. Doping with Co atom significantly increases the electronic transport capability of BNNT and enhances the adsorption reactivity of the tube to CPs. Co-BNNT is expected to be a potential material for removing or detecting CPs pollutants.