Carbon cloth supported hierarchical core-shell NiCo2S4@CoNi-LDH nanoarrays as catalysts for efficient oxygen evolution reaction in alkaline solution

Hierarchical core-shell NiCo2S4@CoNi-LDH nanoarrays grown on carbon cloth (CC) with outstanding electrocatalytic activity for oxygen evolution reaction (OER) were successfully constructed by a three-step hydrothermal strategy. The as-prepared hierarchical core-shell NiCo2S4@CoNi-LDH nanoarrays were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectrometry (EDS) and EDS mapping technologies. Electrochemical measurements showed that the OER catalytic activity of as-obtained NiCo2S4@CoNi-LDH catalyst could be tuned by the molar ratio of Co/Ni in CoNi-LDH. Experiments uncovered that NiCo2S4@Co1Ni4-LDH catalyst prepared at the Co/Ni molar ratio of 1:4 exhibited the strongest OER electrocatalytic activity. To deliver the current densities of 100 mA cm−2, the as-obtained NiCo2S4@Co1Ni4-LDH catalyst required the overpotential of 337 mV in 1.0 M KOH solution. After continuously catalyzing for 40 h, the voltage curve hardly waved, presenting excellent long-term stability. The present work is a useful attempt for constructing highly active and cost-effective OER catalyst.