Growth of needle-like RuO2 nanocrystals on carbon nanotubes and their field emission characteristics

RuO2 Nanorods on Electrospun Carbon Nanofibers for Supercapacitors

“…In Figure d, as the annealing temperature increases from 180 to 220 to 300 °C, I D / I G increases and L a decreases, indicating that a more disordered carbon structure is formed. Thus, more crystallized RuO 2 nanoparticles grown on the CNF at high temperature induce higher stresses between the carbon layers and eventually interfere with the carbon layer stack . The change in annealing temperature significantly alters the degree of crystallinity of RuO 2 , the crystal size, and the sp 3 -to-sp 2 ratio of the carbon structure. − Therefore, RuO 2 nanoparticles have many amorphous structures at 180 °C, and the crystal structure is increased at 300 °C, consistent with the crystal phase transition of RuO 2 at elevated temperatures in previous papers. ,, An RuO 2 -CNF composite with less crystallized RuO 2 nanoparticles is expected to improve the electrochemical performance through its excellent electrical conductivity, because the large-crystal-sized carbon plane facilitates charge transfer.…”

“…For the RuO 2 -CNF composites (Figure c), there are two characteristic Raman modes, E g (515 cm –1 ) and A 1g (624 cm –1 ), which can confirm the formation of RuO 2 nanoparticles grown on the CNFs . In addition, these two bands become strong and sharp when the annealing temperature increases, which may be ascribed to an increase in the degree of crystallization of RuO 2 , since the high intensity of the peak and the large signal strength indicate the crystal formation. − Figure d summarizes I D / I G (the ratio of the integrated intensity of the D peak to that of the G peak) and the crystalline width L a ( L a = 4.4/( I D / I G )) from the Raman spectra . Generally, the well-defined Raman spectra reflect the excellent crystallinity of RuO 2 in the composite.…”

“…44−46 Figure 4d summarizes I D /I G (the ratio of the integrated intensity of the D peak to that of the G peak) and the crystalline width L a (L a = 4.4/(I D /I G )) from the Raman spectra. 47 Generally, the welldefined Raman spectra reflect the excellent crystallinity of RuO 2 in the composite. In Figure 4d, as the annealing temperature increases from 180 to 220 to 300 °C, I D /I G increases and L a decreases, indicating that a more disordered carbon structure is formed.…”

“…Thus, more crystallized RuO 2 nanoparticles grown on the CNF at high temperature induce higher stresses between the carbon layers and eventually interfere with the carbon layer stack. 47 The change in annealing temperature significantly alters the degree of crystallinity of RuO 2 , the crystal size, and the sp 3 -to-sp 2 ratio of the carbon structure. 48−50 Therefore, RuO 2 nanoparticles have many amorphous structures at 180 °C, and the crystal structure is increased at 300 °C, consistent with the crystal phase transition of RuO 2 at elevated temperatures in previous papers.…”

Synthesis of IrO2 nanocrystals on carbon nanotube bundle arrays and their field emission characteristics

“…For practical CNTs-based field emission devices the emission current density, uniformity, and stability of CNTs need to be improved. The field emission properties of CNTs may be improved by attaching or doping the CNTs with metaloxides, such as ZnO [8], MgO [9], iron oxide [10], and RuO 2 [11,12] to enhance the emission sites. The synthesized metal-oxide/CNTs showed a lower turn-on field compared with the pristine CNTs.…”