Hydrothermal Synthesis and Optical, Magnetic, and Supercapacitance Properties of Nanoporous Cobalt Oxide Nanorods

Abstract

Nanoporous cobalt oxide nanorods were synthesized by a hydrothermal method. Transmission electron microscopy analysis showed that the individual Co 3 O 4 nanorods have a nanoporous structure, consisting of the textured aggregations of nanocrystals. Optical properties of Co 3 O 4 nanorods were characterized by Raman and UV−vis spectroscopy. Magnetic property measurement shows that Co 3 O 4 nanorods have a low Néel transition temperature of 35 K. We observed quite significant exchange bias for nanoporous Co 3 O 4 nanorods, indicating the existence of magnetic coupling between the nanocrystals in Co 3 O 4 nanorods. When applied as electrode materials in supercapacitors, Co 3 O 4 demonstrated a high capacitance of 280 F/g.