Construction of unique NiCo2S4@Ni3V2O8 hierarchical heterostructures arrays on Ni foam as an efficient electrocatalyst with high stability for water oxidation

Abstract

The development of high efficiency and stable electrocatalysts for the electrochemical water oxidation reaction (WOR) is a grand bottleneck in chemical energy storage and conversion. This article describes a simple co-precipitation route to deposit hierarchical NiCo2S4@Ni3V2O8 core/shell hybrid on conductive nickel foam electrode by a simple two-step process. When it is firstly used as the 3D substrates electrode, the NiCo2S4@Ni3V2O8 material makes use of both components and provides excellent water oxidation activity, 35 mA cm−2 was achieved at a overpotential of 290 mV, which is better than the benchmark of IrO2 electrodes (320 mV of overpotential at 35 mA cm−2) and 13 mA cm−2 at 1.47 V with excellent durability. The enhanced water oxidation performance of the NiCo2S4@Ni3V2O8 materials is mainly benefiting from its particular core/shell structure, which exhibits big surface areas, and fast electron and ion transfer. Ni3V2O8 shell protects NiCo2S4 core from oxidation in the in alkaline electrolytes and improves stability of NiCo2S4@Ni3V2O8.This indicates that most metal vanadates oxides-based electrodes are promising as an efficient electrocatalyst and shows the advantages of the interfacial effect, which provide a new idea toward high-performance flexible water oxidation fabrication of robust and cheap catalyst sample.