Synergistic effect of nanosheet-array-like NiFe-LDH and reduced graphene oxide modified Ni foam for greatly enhanced oxygen evolution reaction and hydrogen evolution reaction

Abstract

Herein, we have prepared a series of highly efficient bifunctional electrocatalytic composites, Ni_xFe₁-LDH/rGO/NF (x = 3, 2, 1), with vertically staggered NiFe-LDH nanosheets grown on nickel foam uniformly modified with reduced graphene oxide through a simple green hydrothermal method. The as-obtained nanosheet-array-like composites exhibit excellent performance for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). In particular, Ni₂Fe₁-LDH/rGO/NF requires 228 and 109 mV for the OER and HER in 1 M KOH at 10 mA cm⁻², respectively. Moreover, when it is directly used as both cathode and anode at the same time for overall water splitting, it only requires 1.62 V to achieve 10 mA cm⁻². The as-prepared Ni₂Fe₁-LDH/rGO/NF composite shows excellent electrocatalytic performance, which is ascribed to the unique array-like nanosheet framework with exposed paths, the synergy between Ni₂Fe₁-LDH and rGO, and the vertically staggered growth of Ni₂Fe₁-LDH on the rGO/NF substrate improving the stability. This strategy can also be applied to create composites of other metal compositions with a nanosheet-array-like structure as efficient electrocatalysts for the development of efficient clean renewable energy.