Novel Design of Highly Stable Ni3S2 Core @NiCo-LDH Shell Nano-Grasses Electrocatalysts for Oxygen Evolution Reaction at Intermittent Conditions

Abstract

For a sustainable energy system, large-scale hydrogen production under intermittent renewable energy sources from solar and natural wind system are currently necessary. However, the price of noble metal-based catalysts and their poor stability limit their large-scale application. Herein, a Ni3S2@NiCo-LDH composite electrocatalysts with a core@shell structure was successfully synthesized via an in-situ hydrothermal method coupling with an electrodeposition process. The obtained Ni3S2@NiCo-LDH/NF electrode exhibited superb OER performance with low overpotentials of 305 and 346 mV to deliver current densities of 50 and 100 mA cm-2, respectively. Meanwhile, this electrode also stabilized at 100 mA cm-2 in the alkaline solution at both continuous and intermittent conditions without degradation for over 24 hours. The remarkable electrocatalytic activity should be attributed to the unique morphology of nano-grasses (core) with nanoflake structure (shell) with a high density of exposed active sites, rich defects and large surface areas. This electrocatalyst design could be applied for the large-scale hydrogen production using electricity generated from intermittent renewable energy.