Interfacial electronic regulation on NiCo2O4 nanowires@NiFe-LDH nanosheets heterostructure for efficient oxygen evolution

Abstract

Developing cost-effective, highly efficient, and durable oxygen evolution reaction (OER) catalysts is critical for improving the efficiency of hydrogen production from water splitting. Herein, we reported a novel OER catalyst composed of NiFe layered double hydroxide (NiFe-LDH) nanosheets on NiCo2O4 nanowires (NiCo2O4@NiFe-LDH) supported on carbon cloth through the hydrothermal method and subsequent electrodeposition. The three-dimension (3D) hierarchical architecture facilitates the diffusion of electrolyte ions and O2 release. Experimental results demonstrate that the electrons transfer from the highly conductive NiCo2O4 nanowires to the NiFe-LDH sheets, which could expedite the charge transfer significantly. Importantly, the tunable adsorption/desorption nature of the oxygenated intermediates was achieved through the local delocalization of spin state at the heterointerface through the bridging O2-. Benefiting from the heterostructure and synergistic effects between different components, the optimized NiCo2O4@NiFe-LDH-2 exhibits excellent OER performance with a low overpotential of 270 mV at 50 mA cm−2, a small Tafel slope of 74 mV dec−1 and a good durability for 25 h in 1 M KOH. This work provides a novel approach to fabricate advanced OER catalysts and is expected to be extended to other materials for energy conversion applications.