Mechanochemical Preparation of Edge‐Selectively justify Hydroxylated Graphene Nanosheets Using Persulfate via a Sulfate Radical‐Mediated Process
Cuiyu Huang, Jin Shyong Lin, Heqing Tang, Qin Wang, Tetsuro Majima, Nan Wang, Zhihong Luo, Lihua Zhu
Abstract
Abstract The production of water‐dispersed graphene with low defects remains a challenge. The dry ball milling of graphite with additives produces edge‐selectively functionalized graphene. However, the “inert” additives require a long milling time and cause inevitable in‐plane defects. Here, the mechanochemical reaction of graphite with persulfate solved the above drawback and produced edge‐selectively hydroxylated graphene (EHG) nanosheets through a 2 h ball‐milling and a subsequent 0.5 h sonication. The mechanochemical cleavage of persulfate yielded SO 4 ⋅ − to spontaneously oxidize graphite to form the carbon radical cations selectively at edges, followed by hydroxylation with water of moisture. Because the O−O bond dissociation energy of persulfate is 20 % of the graphitic C−C bond, the rather low milling energy allowed the hydroxylation of graphite at edges with nearly no in‐plane defects. The obtained EHG showed high water‐dispersibility and excellent photothermal and electrochemical properties, thereby opening up a new door to fabricate graphene‐based composites.