Synthesis of 3D CoO nanowires supported NiFe layered double hydroxide using an atmospheric pressure microplasma for high-performance oxygen evolution reaction

Abstract

A novel approach was designed to fabricate three-dimensional (3D) hierarchical-structure cobalt oxide (CoO) supported NiFe layered double hydroxide (LDH) nanosheets array on Ni foam (NF). Facile preparation was realized by dielectric barrier discharge (DBD) microplasma, which owns a great chemical reactivity to obtain 3D open structures. The prepared 3D CoO@NiFe LDH/NF emerges a superior catalytic activity for oxygen evolving reaction (OER) in alkaline media, which only demands an overpotential of 225 mV at 20 mA cm−2. The as-prepared electrocatalyst provides excellent long-term durability (>80 h) and a high turnover frequency (TOF) of 0.59 mol O2 s−1 at 350 mV. Compared to the 2D NiFe LDH/NF, the overpotential of CoO@NiFe LDH/NF can be directly reduced 52 mV at 20 mA cm−2. The intermediate products of hydroxyl radicals (OH) were identified and the possible synthesis mechanism was tentatively proposed. We believe the present work could provide new insight for the rational design of other efficient OER electrocatalysts by DBD microplasma.