Highly Active Three-Dimensional NiFe/Cu2O Nanowires/Cu Foam Electrode for Water Oxidation

Water splitting is of paramount importance for exploiting renewable energy-conversion and -storage systems, but is greatly hindered by the kinetically sluggish oxygen evolution reaction (OER). In this work, a three-dimensional, highly efficient, and durable NiFe/Cu2O nanowires/Cu foam anode (NiFe/Cu2O NWs/CF) for water oxidation in 1.0m KOH was developed. The obtained electrode exhibited a current density of 10mAcm(-2) at a uniquely low overpotential of =215mV. The average specific current density (j(s)) was estimated, on the basis of the electrocatalytically active surface area, to be 0.163mAcm(-2) at =310mV. The electrode also displayed a low Tafel slope of 42mVdecade(-1). Moreover, the NiFe/Cu2O NWs/CF electrode could maintain a steady current density of 100mAcm(-2) for 50h at an overpotential of =260mV. The outstanding electrochemical performance of the electrode for the OER was attributed to the high conductivity of the Cu foam and the specific structure of the electrode with a large interfacial area.