以石墨烯与粘土间的插层实现石墨烯片层的稳定分散

摘要

The reduction of graphene oxide (GO) leads to the re-stacking/agglomeration of graphene layers,which results in their precipitation from an aqueous dispersion.A laponite colloid was used to prevent re-stacking and stabilize an aqueous dispersion of reduced graphene oxide (RGO) by dispersing GO in the colloid,followed by reduction with hydrazine hydrate under microwave radiation.Results indicate that re-stacking is prevented as proven by the disappearance of the RGO (002) peaks in the XRD pattern.A laponite/RGO (w/w:1∶1) dispersion shows the highest stability under centrifugation at 10 000 rpm and the largest BrunauerEmmett-Teller surface area,which is 17.6％ higher than that of RGO and 34.4％ higher than laponite.Electrostatic interaction between negatively-charged RGO layers and positively-charged laponite edges lead to an intercalation structure,which is responsible for the non-stacking RGO and its stable dispersion in water.This intercalation method offers an alternative way for the dispersion of graphene layers.%氧化石墨烯的还原反应将导致石墨烯片层的复叠和团聚,使其在水分散液中发生沉淀.本文采用粘土胶体帮助还原氧化石墨烯在水中的稳定分散,并阻止石墨烯片层的复叠.氧化石墨烯水分散液与粘土胶体相混合之后,在微波辅助条件下,对氧化还石墨烯进行还原.当粘土与还原氧化石墨烯的质量比是1∶1时,混合液的分散稳定性最好.XRD图谱中还原氧化石墨烯的(002)峰消失,可见石墨烯片层没有发生复叠.还原氧化石墨烯与粘土片层之间,由于静电相互作用和空间位阻效应,形成了插层结构.由透射电镜观察可知,还原氧化石墨烯表面均匀分布着粘土片层.粘土与还原氧化石墨烯的混合物的比表面积高于还原氧化石墨烯17.6％.这种物理插层法为石墨烯片层的稳定分散提供了另一种思路.