State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, China.
Chemphyschem. 2012 Feb;13(3):774-9. doi: 10.1002/cphc.201100864. Epub 2012 Jan 31.
Many outstanding properties of graphene are blocked by the existence of structural defects. Herein, we propose an important healing mechanism for the growth of graphene, which is produced via plasma-enhanced chemical vapor decomposition (PECVD), that is, the healing of graphene with single vacancies by decomposed CH(4) (hydrocarbon radical CH(x), x=1, 2, 3). The healing processes undergo three evolutionary steps: 1) the chemisorption of the hydrocarbon radicals, 2) the incorporation of the C atom of the hydrocarbon radicals into the defective graphene, accompanied by the adsorption of the leaving H atom on the graphene surface, 3) the removal of the adsorbed H atom and H(2) molecule to generate the perfect graphene. The overall healing processes are barrierless, with a huge released heat of 530.79, 290.67, and 159.04 kcal mol(-1), respectively, indicative of the easy healing of graphene with single vacancies by hydrocarbon radicals. Therefore, the good performance of the PECVD method for the generation of graphene might be ascribed to the dual role of the CH(x) (x=1, 2, 3) species, acting both as carbon source and as defect healer.
石墨烯的许多优异性能都被结构缺陷所阻碍。在此，我们提出了一种重要的石墨烯生长修复机制，即通过等离子体增强化学气相分解（PECVD），利用分解的 CH(4)（碳氢自由基 CH(x)，x=1,2,3）来修复具有单空位的石墨烯。修复过程经历三个演化步骤：1）碳氢自由基的化学吸附，2）碳氢自由基的 C 原子掺入缺陷石墨烯中，同时留下的 H 原子吸附在石墨烯表面，3）吸附的 H 原子和 H(2)分子的去除，生成完美的石墨烯。整个修复过程是无势垒的，释放出的热量分别为 530.79、290.67 和 159.04 kcal/mol，表明碳氢自由基很容易修复具有单空位的石墨烯。因此，PECVD 方法生成石墨烯的优异性能可能归因于 CH(x)（x=1,2,3）物种的双重作用，既作为碳源又作为缺陷修复剂。
