3D core-shell structured NiFe layered double hydroxide with NiCo2O4 as an efficient electrocatalysts for oxygen evolution reaction

Abstract

In this work, a 3D core-shell NiFe-LDH/NiCo2O4/NF nanostructured composite with intimate interface have been successfully synthesized via a two-step hydrothermal approach. The core-shell composites demonstrate excellent electrocatalytic behavior due to its unique 3D core-shell microstructure and the optimized electron migration pathway. When NiFe-LDH anchors on the surface of NiCo2O4, the formation of Fe3+, Ni3+ and Co2+ in the composite induced by electrons migrate from Fe2+ and Ni2+ in the NiFe-LDH shell to Co3+ in the NiCo2O4 core can significantly promote charge transfer across interface and thereby boosting its oxygen evolution reaction (OER). In comparison to its single-component and hydroxide, the composite delivers a low overpotential of 363 mV for 50 mA cm−2, a small Tafel slope of 53.03 mV·dec−1, and satisfactory long-term stability, which makes it comparable to commercial IrO2 catalysts. These results show on how 3D core-shell architecture and valence states of metal oxides influence on OER performance in NiFe-LDH/NiCo2O4 electrocatalysts and provide new insights for regulating LDH-based electrocatalysts.