H_2O分子在石墨烯扶手型边缘吸附的研究  

The study of H_2O molecules adsorption on graphene armchair edge

作　　者：刘健康[1] 何国柱[1] 

机构地区：[1]四川农业大学,都江堰611830

出　　处：《四川大学学报（自然科学版）》2012年第3期635-638,共4页Journal of Sichuan University(Natural Science Edition)

摘　　要：类似石墨表面,石墨烯可以吸附和脱附各种原子和分子,石墨烯比石墨具有更大表面积,因此,石墨烯的表面性能被广泛关注.然而较少被关注的是石墨烯边缘C原子的性能.石墨烯边缘C原子由于存在未配对的电子,因此具有更强的反应活性.本文采用了Self-Consistent-Charge Density Functional Tight Binding(SCC-DFTB)方法对H_2O分子在石墨烯扶手型边缘的吸附现象进行了研究.研究发现,石墨烯边缘的峰位C原子具有很好的吸附性,吸附能大约为-0.109～-0.768 eV,明显大于石墨烯表面原子的吸附能(-0.018～-0.047eV).当H_2O分子被吸附时,有电荷转移现象发生,使得H_2O分子极性增强,增加了吸附性能.当H_2O分子中的O原予朝向C原子时,H_2O分子可与两个谷位C原子、两个峰位C原子形成环状物,是没有O-H键分解的吸附中最稳定的结构,有明显的电荷转移现象.Like graphite, graphene can adsorb and disadsorb many molecules and atoms. Graphene has bigger surface, so it was widely researched by chemists. However, seldom studies are carried out for the edge atoms which are more active than the surface atoms due to unpaired electrons in graphene. In this paper, we applied the selfconsistentcharge density functional tight binding （SCCDFTB） method to probe the adsorption phenomenon on the graphene edge atoms. Our research found that the absorption energy of edge atoms ranges from -0.109 to -0.768 eV, which is much larger than that of the surface atoms （-0.018^-0.047 eV）. Through the analysis of the charge transfer we found that when H2O is adsorbed on C atoms, the charge transfer enhances the molecular polarity of H2O. When the O atom of H2O is toward the C atom of graphene, H2O and graphene form the ring structure, a best stable structure among the nondissociation adsorptions.

关 键 词：石墨烯 吸附 电子密度分布 态密度 

分 类 号：O485[理学—固体物理]