基于缺陷曲率对含有V_1～V_4空位(5,5)单壁碳纳米管[1+1]和[2+1]加成反应的第一性原理研究  

[1+1] and [2+1] Additions on a(5,5) Single-Walled Carbon Nanotube with V_1～V_4 Vacancies Based on Defect Curvature:A First Principles Study

作　　者：李磊[1] 贾桂霄[1,2] 王晓霞[1] 吴铜伟 宋希文[1,2] 安胜利[1,2] 

机构地区：[1]内蒙古科技大学材料与冶金学院,包头014010 [2]内蒙古自治区新型功能陶瓷与器件重点实验室,包头014010

出　　处：《化学学报》2017年第3期284-292,共9页Acta Chimica Sinica

基　　金：内蒙古自然科学基金(No.2016MS0513);内蒙古科技大学青年人才孵化器(No.2014CY012)资助~~

摘　　要：本工作使用GGA-PBE方法研究了H和O在含有V_1~V_4空位(5,5)单壁碳纳米管[1+1](H/[1+1])和[2+1](O/[2+1])加成反应的结合能、几何和电子结构.基于方向曲率理论提出的缺陷曲率包括原子曲率(KM-def)和键曲率(K_(D-def))预测了空位缺陷区不同原子和键的加成反应活性.计算结果表明,不管是[1+1]还是[2+1]加成,V_1和V_3空位缺陷中含有悬空键的C原子化学活性最强,且在[2+1]加成反应中C与O原子形成了羰基;对空位缺陷区其它原子或键,H与(5,5)管V_1~V_4空位缺陷区的原子结合能随K_(M-def)的增大而增大;O加成在大K_(D-def)的C—C键时,C—C键易被打断,形成C—O—C产物结构,且相应的结合能较大;O加成在小K_(D-def)的C—C键时,C—C键未被打断,形成三元环产物结构.H/[1+1]和O/[2+1]加成反应结合能除了主要受曲率的影响,还受到参与反应的C原子在(5,5)管最高占据分子轨道的电荷密度以及分波态密度的影响.这些研究将为含有空位缺陷碳纳米管的表面修饰提供理论依据.Binding energies, geometric and electronic structures for [1＋1]（H/[1＋1]） and [2＋1]（O/[2＋1]） additions of H and O atoms on a（5,5） single-walled carbon nanotube with V1-V4 vacancies are studied using a GGA-PBE method in this work. Defect curvature proposed on the basis of directional curvature theory, including atomic curvature（KM-def） and bond curvature（K（D-def））, is used to predict the reactivities of different atoms and bonds at the defect structural area. We find that the existence of vacancy defects enhances the H and O adsorption ability on the（5,5） tube. The calculated results show that in the V1 and V3 defects the C atoms with two-coordination have the strongest chemical activity for [1＋1] and [2＋1] additions, and among which the C atoms participated into [2＋1] additions form carbonyl groups with O. For other atoms and bonds at the defect structural area, the binding energies of one H atom on the（5,5） tube monotonously increases with the increase of K（M-def）.When the K（D-def） of C—C bonds for the O/[2＋1] additions are large, the C—C bonds are easily broken, and they are corresponding to adducts with the C—O—C configuration structures and large binding energies. When the K（D-def） of C—C bonds are small, the C—C bonds are not broken, and they are corresponding to adducts with the closed-3MR（three-member ring） structures. The binding energies for the H/[1＋1] and O/[2＋1] additions on the（5,5） tube mainly are determined by the curvature and affected by the electronic density in frontier orbital and partial density of state（PDOS） of C atoms participated in the reactions. The large electronic density in the highest occupied molecular orbital（HOMO） and large PDOS of C atoms near the Fermi level strengthen the adsorption of H and O atoms on the（5,5） tube. This study will provide a theoretical basis for surface modifications of carbon nanotubes with vacancy defects.

关 键 词：碳纳米管 空位 缺陷曲率 电子结构 加成反应性 

分 类 号：O621.256.7[理学—有机化学]