The adverse effects caused by global climate warming continue to be a great impetus to develop electrocatalytic water splitting technology for hydrogen source production. However, there is an urgent necessity but it is still a significant challenge to explore electrocatalysts with excellent performance, low cost, and environmental benignity for expediting the oxygen evolution reaction (OER) owing to the sluggish reaction kinetics. Fe-based materials, especially FeOOH, have great potential as OER electrocatalysts but suffers from poor electrical conductivity. Herein, we rationally designed and successfully synthesized FeOOH nanosheet arrays supported on alkali-treated nickel foam (FeOOH NSAs/ATNF) and applied it as an electrocatalyst toward OER. The FeOOH NSAs/ATNF catalyst exhibited outstanding performance with small overpotential, fast kinetics and superior stability in alkaline medium. Our research opens up a facile and effective approach to develop cost-effective and high-performance electrocatalysts for energy conversion, especially for these Fe-based materials with poor electrical conductivity. (C) 2020 Elsevier Inc. All rights reserved.