Synergistic effect of NF and rGO in preparing 3D NiFe-LDH/rGO@NF composites on electrocatalysts performance

Abstract

In order to overcome the defects of the layered double hydroxide (LDH) with poor electrical conductivity and the limited active sites, in this paper, an advanced three-dimensional (3D) NiFe-LDH/rGO@NF composite material was designed and prepared by reducing graphene oxide (rGO) flakes on nickel foam (NF) and growing NiFe-LDH nanosheets in-situ. Excitingly, the 3D NiFe-LDH/rGO@NF composites exhibited excellent electrocatalytic performance. By analyzing the microstructure and electrochemical properties of NiFe-LDH/rGO@NF, the synergistic effect of 3D-NF and 2D-rGO on oxygen evolution reaction (OER) and electrocatalysis performance in 3D NiFe-LDH/rGO@NF was explored. The results show that the composite structure composed of 2D rGO and 3D NF is synergistic with each other. On the one hand, this composite structure can very effectively increase the specific surface area to inhibit agglomeration and expose abundant active sites of LDH. On the other hand, both rGO and NF can enhance the electrical conductivity of NiFe-LDH and improve the transportability of electrons and ions due to the excellent electrical conductivity. Additionally, the 3D NiFe-LDH/rGO@NF exhibits excellent OER catalytic performance, with an overpotential of 277 mV at 50 mA/cm2 and a Tafel slope of 59.9 mV/dec.