Improved Electrocatalytic Performance in Overall Water Splitting with Rational Design of Hierarchical Co3O4@NiFe Layered Double Hydroxide Core-Shell Nanostructure

摘要

The development of low-cost and highly reactive electrocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in basic media is still a great challenge. Herein, we design a three-dimensional Co3O4@NiFe-LDH (LDH: layered double hydroxide) core-shell nanostructure on Ni foam, in which the core Co3O4 nanowires play a key role in the stability and the shell NiFe-LDH nanosheets provide the main active sites for electrocatalytic water splitting. The as-prepared Co3O4@NiFe-LDH exhibits excellent electrocatalytic activity for OER with a low overpotential of 269mV at a current density of 100mAcm(-2), a small Tafel slope of 66mVdec(-1), and excellent stability without degradation over 40h. Furthermore, the sample also demonstrates robust performance for HER with a low overpotential of 74mV at a current density of 10mAcm(-2). Most importantly, when employing the Co3O4@NiFe-LDH/NF as both anode and cathode, only 1.56V is needed to achieve a current density of 10mAcm(-2), which is lower than the combination of Pt/C and IrO2 catalysts for overall water splitting. This work provides a significant strategy toward the rational design of novel core-shell electrocatalysts for overall water splitting.