Electrodeposition of hierarchical manganese oxide on metal nanoparticles decorated nanoporous gold with enhanced supercapacitor performance

A novel three dimensional nanoarchitecture of manganese oxide nanosheets/Pt@nanoporous gold (MnOx/Pt@NPG) was designed and synthesized by galvanostatic electrodepositon for supercapacitors application. Nanoporous gold (NPG) membrane was fabricated by a dealloying method as a current collector and discontinuous platinum nanoparticles were pulse electrodeposited on NPG. The morphology and chemical composition of the MnOx/Pt@NPG products were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The electrochemical properties of the as-prepared MnOx as an electrode material for supercapacitor were investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy measurements in 1 M Na2SO4 electrolyte. Importantly, the optimized MnOx/Pt@NPG hybrid electrodes obtain a maximum specific capacitance of 775 F g−1 at 1 A g−1 (about two times larger than that of MnOx/NPG electrodes with 404 F g−1), about half of the internal resistance of MnOx/NPG electrodes and excellent cycling stability, making it a promising candidate for supercapacitors.