▎ 摘　　要

It is highly essential but challengeable to explore the earth-abundant and low-cost oxygen evolution reaction catalysts to replace Ir- or/and Ru-based ones. In this article, we report an in situ growth of ultrathin NiFe layered double hydroxide nanosheets on reduced graphene oxide in formamide aqueous solution followed by simple chemical reduction. These ultrathin layered double hydroxide nanosheets in the composite occur in single- or multi-layer forms on reduced graphene oxide matrix. Consequently, the obtained catalyst exhibits the enhanced BET surface area and electrochemically active surface area, and low mass transfer resistance. This electrocatalyst displays the excellent OER activity with a small onset potential of 233 mV. Additionally, it only requires an overpotential of 254 mV to achieving current density of 10 mA cm(-2), and can gives a current density of 70.60 mA cm(-2) at overpotential of 300 mV in 0.1 M KOH. It also demonstrates the robust long-time electrochemical durability. (C) 2019 Elsevier Inc. All rights reserved.