对苯二胺功能化还原氧化石墨烯的结构和官能团变化

采用一步水热回流法,选取对苯二胺(PPD)对氧化石墨烯(GO)进行还原与改性处理,制备了功能化还原氧化石墨烯(GOP-X).采用傅里叶变换红外光谱(FTIR)、X射线光电子能谱(XPS)及X射线衍射(XRD)等研究了PPD与GO的反应作用类型及结构变化.结果表明,随着PPD与GO质量比的增加,GOP-X层间距(d值)先增大后减小,GOP-X共轭结构逐渐恢复,与溶剂分子作用时,层间距增幅呈减小趋势,并最终趋于恒定.PPD单体与GO反应时存在3种键合类型:(1)GO含氧官能团和PPD分子之间的氢键作用(C—OH…H2N—X);(2)质子化PPD与弱酸性GO带负电位置之间的离子键作用(—COO-H3+N—X);(3)PPD中氨基(NH2)与GO含氧官能团之间形成的共价键作用.与GO中羧基(COOH)的酰胺化反应将先于与环氧基(C—O—C)的亲核取代反应.提出了相应的作用机理.

Changes of Structure and Functional Group of Reduction of Graphene Oxide with p-Phenylene Diamine

The p-phenylene diamine ( PPD ) were selected as reducion and modification agent to prepare functionalized and reduced graphene ( GOP-X ) by one-step simple refluxing method. Infrared spectrum ( FTIR) , X-ray photoelectron spectroscopy( XPS) , X-ray diffraction( XRD) and UV-Vis absorption spectrum were used to investigate the reaction types and structure changes between PPD and graphene oxide( GO) . The results show that the d-spacing of GOP-X layers increases firstly and then decreases with the increase of X( the mass ratio of PPD and GO ) , and the conjugated structure gradually restored; when the solvent molecular interaction, the amplification of the d-spacing decrease to a steady figure. Three types of bonds between PPD and GO were proposed:(Ⅰ) hydrogen-bonding interaction between the oxygen-containing functional groups of GO and the PPD molecules ( C—OH…H2 N—X ); (Ⅱ) ionic bonding in protonating amine by the weakly acidic sites of the GO layers(—COO-H3+N—X); (Ⅲ) covalent bonding from amidation and nucleophilic addition reactions between the amie in PPD ( NH2 ) and the oxygen containing groups of GO. Furthermore, the NH2 prefers to react first with the carboxyl group( COOH) and then with the epoxide group( C—O—C) , and the relative action mechanisms were also described.