Nickel foam supported mesoporous NiCo2O4 arrays with excellent methanol electro-oxidation performance†
In this study, nickel foam supported NiCo2O4 nanosheet and nanocloth arrays are directly prepared by a mild hydrothermal method and applied to methanol electro-oxidation. Several techniques, including powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive spectroscopy (EDS) and nitrogen absorption measurements, have been employed to characterize the physicochemical properties of the as-prepared catalysts. The electrocatalytic performances are investigated by cyclic voltammetry (CV), chronoamperometry (CA) measurements and electrochemical impedance spectroscopy (EIS). Impressively, NiCo2O4 nanosheet and nanocloth arrays both deliver excellent electrocatalytic performance for methanol electro-oxidation in an alkaline medium, including low onset potential (0.19 V, 0.16 V), high current densities (111 mA cm−2, 134 mA cm−2) and a desirable electro-oxidation stability (90%, 88%). The excellent electrocatalytic performances of nickel foam supported NiCo2O4 nanosheet and nanocloth arrays originate from their unique 3D mesoporous architecture, which can provide adequate open spaces and shorter ion diffusion paths to facilitate rapid ionic transportation.