▎ 摘　　要

It is important to develop an efficient and low cost electrocatalyst for oxygen evolution reaction (OER) to improve the efficiency of hydrogen production from electrolytic water. Herein, we rationally design vertical few layer graphene (VFLG)/NiO core-shell nanoflake arrays as advanced binder-free OER catalyst in water splitting for the first time. Due to the improved conductivity, rich catalytic active sites and the unique open porous framework structure, the VFLG/NiO electrocatalyst exhibits outstanding electrocatalytic OER performance with a low overpotential (420 mV at 10 mA cm(-2)) and a small Tafel slope (46.3 mV dec(-1)) in alkaline solution. Our proposed design strategy provides a useful reference for the construction of other high-performance integrated core/shell arrays for electrocatalysis and energy storage.