In situ growth of NiCoFe-layered double hydroxide through etching Ni foam matrix for highly enhanced oxygen evolution reaction

It is of great significance to develop the nonprecious metal oxide electrocatalysts toward oxygen evolution reaction (OER) for water splitting. Herein we report an in-situ growth of the ternary NiCoFe-layered double hydroxide nanosheets on surface etching nickel foam (NiCoFe LDHs/NF) without adding any nickel precursor. In this method, etching Ni matrix by Fe3+ not only provides the slowly released nickel ions, but also intensifies the Fe–Ni interaction between the directly grown active species and Ni foam. Therefore the composition, electronic structure, and morphology of the electrocatalysts can be easily regulated only by adjusting Co2+:Fe3+ ratio in the precursor solution. The obtained NiCo1Fe1 LDH/NF, which is formed in 1:1 Co2+:Fe3+ solution, has highest content of Ni3+ and Co3+ active sites and the largest electrochemical active area. It exhibits an outstanding OER performance with a small overpotential of 231 mV at 10 mA cm−2 and excellent durability at 50 mA cm−2 in 1.0 M KOH solution.