Morphology controllable synthesis and electrochemical properties of MnO_x nanoparticles on carbon fibre surface

Abstract

Manganese oxides (MnO_x) with different morphologies were synthesised on carbon fibre surfaces by using a hydrothermal method. Scanning electron microscope (SEM) observation results showed that ultra-thin nanosheets, flower-like nanosheets, mixture of nanorods and thick nanosheets, and nanorods of MnO_x could be synthesized with different amounts of nitric acid in hydrothermal reaction solutions. Fourier transform infrared (FTIR) spectroscopy was employed to prove the successful formation of MnO_x nanoparticles. Specific surface area analysis indicated that flower-like nanosheets of MnO_x nanoparticles had the highest specific surface area (67 m² g⁻¹), which made it promising as an electrode material. X-ray diffraction (XRD) pattern revealed that the flower-like nanosheets of MnO_x nanoparticles were pure monoclinic phase of K-birnessite K_0·27MnO₂.0·54H₂O. Cyclic voltammetry tests demonstrated good rate capability of the sample with unique flower-like structure.

Keywords:

• Hydrothermal
• Morphology
• Nanostructure
• Manganese oxides

Acknowledgements

This work is supported by the National Natural Science Foundation of China (nos. 51003057, 51003056, 21201119 and 21071096), the National Basic Research Program of China (973 Program, no. 2014CB643306), the Innovation Program of Shanghai Municipal Education Commission (no. 13YZ086) and the Science and Technology Program of Shanghai Maritime University, China, under Grant nos. 20120073 and 20120071.