An improved Hummers method derived graphene oxide wrapped ZIF-8 polyhedron derived porous heterostructure for symmetric supercapacitor performance

Abstract

Heterostructure materials are intriguing because they may combine two or more building blocks that produce novel heterointerfaces with exceptional features. By exposing more interfaces and active sites, their utility in electrochemical applications is further expanded when they are used to form large-scale 3D frameworks. This study uses improved graphene oxide (IGO) and GO to form a heterojunction (ZIF-8/IGO). The interface between ZIF-8 and IGO accelerated the transfer of thermally obtained electrons from ZIF-8-NC to IGO. We focus on developing a 2D heterostructure mixed porous system based on differences in the density of oxygen-containing functional groups of improved graphene oxide (IGO) and commercially accessed graphene oxide (GO) while forming a composite with ZIF-8. IGO@ZIF-8-NC exhibited a very high capacitance of 352.8 F g⁻¹ as compared to 287.5 F g⁻¹ for GO@ZIF-8-NC at a scan rate of 5 mV s⁻¹ confirming that the former is an excellent supercapacitor electrode owing to the synergistic behaviour at the heterojunction interface. The results on IGO-based electrodes pave the way forward for sustainable capacitive devices.