Facile synthesis of cobalt oxide/reduced graphene oxide composites for electrochemical capacitor and sensor applications

Abstract Reduced graphene oxide sheets decorated with cobalt oxide nanoparticles (Co 3 O 4 /rGO) were produced using a hydrothermal method without surfactants. Both the reduction of GO and the formation of Co 3 O 4 nanoparticles occurred simultaneously under this condition. At the same current density of 0.5 A g −1 , the Co 3 O 4 /rGO nanocomposites exhibited much a higher specific capacitance (545 F g −1 ) than that of bare Co 3 O 4 (100 F g −1 ). On the other hand, for the detection of H 2 O 2 , the peak current of Co 3 O 4 /rGO was 4 times higher than that of Co 3 O 4 . Moreover, the resulting composite displayed a low detection limit of 0.62 μM and a high sensitivity of 28,500 μA mM −1 cm −2 for the H 2 O 2 sensor. These results suggest that the Co 3 O 4 /rGO nanocomposite is a promising material for both supercapacitor and non-enzymatic H 2 O 2 sensor applications.