RuO2 nanoparticles dispersed on carbon nanotubes with high electrochemical activity using N incorporation

The N incorporation into carbon nanotubes (CNTs) supporting ultrafine RuO2 nanoparticles (NPs) has been studied. With increasing N dopant, the Raman spectrum shifts to higher wavenumbers and x-ray photoelectron spectroscopy results show the intensity ratio of graphene- to pyridine-like bonding is reduced. Cross-sectional scanning electron microscope images reveal that the uniform RuO2 NPs are dispersed on CNTs at the N-2 flow rate of 20 sccm. Electrochemical (EC) measurements show N-doped CNTs covered with RuO2 NPs at an N-2 flow rate of 20 sccm provide the optimal capacitive behavior with larger energy density and can be performed at the higher scan rate of 2000 mV s(-1). The distribution of RuO2 NPs on CNT surfaces deduced from N-induced defect sites is the key point in controlling the capacitive characteristics of CNT-RuO2 nanocomposites (NCs). The high capacitance is due to the well-dispersed RuO2 particles on CNTs incorporated with N atoms. Such NCs are promising for energy storage devices with high EC efficiency.