Facile preparation of 3D graphene frameworks as functional modification platform for sensitive electrochemical detection of chloride ions

Abstract

Multilayer graphene oxide(MGO) highly stacked nature restricts its application in the sensor field, and obtaining high-quality 3D graphene remains a significant challenge. Herein, we report the direct use of MGO to synthesize highly dispersed and rich ordered mesoporous 3D reduced graphene oxide frameworks(rGOFs) through a novel improved KOH activation method, which is based on the pre-treatment process of fully adsorbing and fixing the appropriate amount of K + by using the limited interlayer space of MGO and freeze-drying crystallization technology. Surprisingly, different from previous reports that only the micropores and individual macropores have been obtained by conventional KOH activation, we fully confirmed the dense and ordered mesoporous defects on the surface of rGOFs by SEM for the first time, as well as the multilayer stacked structure of rGOFs is in line with the typical 3D structure. Besides, rGOFs have the excellent properties of reduced graphene oxide (rGO) and a particular 3D framework structure, making it an excellent functionalized modification platform. In order to verify the performance of rGOFs as a framework platform, in which amination modification and small-size Ag NPs loading were successfully realized, the constructed Ag@rGOF-NH 2 /GCE sensor detects chloride ions over a wide linear concentration range of 5 μmol L −1 -10 μmol L −1 , with the detection limit as low as 0.1 μmol L −1 (S/N = 3). This work would not only open a new path to synthesize 3D graphene with excellent performance, and the concept of graphene frameworks nanomaterial is proposed for the first time, but also promotes its excellent performance as an ideal matrix platform for other nanomaterials in the field of electrochemical sensing.