A Cost-Efficient Bifunctional Ultrathin Nanosheets Array for Electrochemical Overall Water Splitting

The design of cost-efficient earth-abundant catalysts with superior performance for the electrochemical water splitting is highly desirable. Herein, a general strategy for fabricating superior bifunctional water splitting electrodes is reported, where cost-efficient earth-abundant ultrathin Ni-based nanosheets arrays are directly grown on nickel foam (NF). The newly created Ni-based nanosheets@NF exhibit unique features of ultrathin building block, 3D hierarchical structure, and alloy effect with the optimized Ni5Fe layered double hydroxide@NF (Ni5Fe LDH@NF) exhibiting low overpotentials of 210 and 133 mV toward both oxygen evolution reaction and hydrogen evolution reaction at 10 mA cm−2 in alkaline condition, respectively. More significantly, when applying as the bifunctional overall water splitting electrocatalyst, the Ni5Fe LDH@NF shows an appealing potential of 1.59 V at 10 mA cm−2 and also superior durability at the very high current density of 50 mA cm−2.