MnCo 2 O 4+: X nanowire arrays grown on carbon sponge: Improved electrochemical and catalytic performances

Abstract

MnCo 2 O 4+x nanowire arrays have been successfully grown on carbon sponge (CS) via a simple hydrothermal route with sequential thermal treatment, employing CoSO 4 ·7H 2 O, MnSO 4 ·H 2 O and urea as the initial reactants. The as-prepared product, labeled MnCo 2 O 4+x /CS, was characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), (high resolution) transmission electron microscopy (TEM/HRTEM), nitrogen adsorption-desorption isotherms, Raman spectrometry and X-ray photoelectron spectroscopy (XPS). The experiments showed that the presence of CS could affect the phase and morphology of the final manganese cobaltite. Without the presence of CS, a MnCo 2 O 4.5 phase with spherical microstructures was produced; and with the presence of CS, a mixed phase of MnCo 2 O 4.5 and MnCo 2 O 4 with wire-like nanostructures was obtained. It was found that the final MnCo 2 O 4+x /CS markedly improved the electrochemical and catalytic properties against MnCo 2 O 4.5 . At a current density of 1.0 A g -1 , the as-prepared product exhibited a specific capacitance of 405 F g -1 , which was far higher than 158.8 F g -1 of pure MnCo 2 O 4.5 . Under the same experimental conditions, simultaneously, the MnCo 2 O 4+x /CS catalyst only took ∼6 min for catalyzing 92% of 4-nitrophenol (4-NP) to 4-nitroaniline (4-AP), which was shorter than ∼10 min of the pure MnCo 2 O 4.5 catalyst.