Three-dimensional Co_3O_4@NiCo_2O_4 nanoarrays with different morphologies as electrocatalysts for oxygen evolution reaction

摘要

Oxygen evolution reaction is one of the key factors restricting the whole process of electrolysis of water. In this paper, hydrothermal and calcination method are used to in situ grow Co3O4@NiCo2O4 on nickel foam (NF). The formation of Co3O4@NiCo2O4 nanostructures depends on the different hydrothermal time, which further results in the different growth mechanism of Co3O4@NiCo2O4 nanostructures. The result shows that Co3O4@NiCo2O4-8h, as a catalytic material, could play a synergistic role to largely accelerate the electron transfer process and could be efficiently and persistently used in oxygen evolution reaction. The oxygen evolution reaction activity of Co3O4@NiCo2O4-8h material is significantly improved compared with Co3O4, Co3O4@NiCo2O4-6h and Co3O4@NiCo2O4-10 h. When the current density is 50 mA cm(-2), the overpotential is only 290 mV for Co3O4@NiCo2O4-8h material. The enhanced activity Co3O4@NiCo2O4-8h is attributed to more active site exposure, rapid charge transfer and synergistic catalysis of Co3O4 and NiCo2O4. This work provides a new idea for the development of efficient, stable and environmentally friendly hybrid catalysts. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.