ZnO@MoO3 core/shell nanocables: facile electrochemical synthesis and enhanced supercapacitor performances

Abstract

Core/shell nanostructures often exhibit novel physical and chemical properties. Herein ZnO@MoO₃ core/shell nanocables have been synthesized in large quantities by a simple electrochemical method at room temperature and the shell thickness of MoO₃ can be controlled by changing the deposition time. The synthesized core/shell nanocables were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The inner ZnO nanorod shows a single-crystal structure and has preferential growth in the [0001] direction. The MoO₃ shell also shows a single-crystal structure with a [0001] direction. The prepared ZnO@MoO₃ core/shell nanocables have been successfully employed as supercapacitor electrodes and give a specific capacitance of 236 F g⁻¹ at scan rate of 5 mV s⁻¹, which is much larger than that of MoO₃ nanoparticles. In addition, ZnO@ MoO₃ core/shell nanocables show high electrochemical stability and can withstand over 1000 cycles with no obvious decrease in the specific capacitance.