Nickel Foam-Supported Hierarchical NiCo2S4 Nanostructures as Efficient Electrocatalysts for the Methanol Oxidation Reaction

In this study, hierarchical NiCo2S4 nanostructures have been successfully prepared on Ni foam support using a simple and economical two-step hydrothermal process. The hierarchical NiCo2S4 nanostructure comprises rod-like NiCo2S4 cores enveloped by a thin nanoribbon shell. When the NiCo2S4/Ni foam was employed as an electrode for methanol electrooxidation directly, a current density of 194 mA mg−1 was achieved at 0.60 V. The prepared NiCo2S4/Ni foam demonstrates high electrocatalytic activity and durability in alkaline environments for the methanol oxidation reaction. After 1000 cyclic voltammetry cycles in the alkaline electrolyte, the current density of the hierarchical NiCo2S4 decreased to 72.2% of its initial value, with the loss of catalytic activity during the cycling test attributed to their surface oxidation. These findings suggest the NiCo2S4 sample as a non-noble metal electrocatalyst holds great potential for direct methanol fuel cells.