Local electronic structure of carbon nanotubes consolidated by spark plasma sintering

Local electronic structure of carbon nanotubes (CNTs) consolidated by spark plasma sintering and further oxidized by nitric acid was studied by electron paramagnetic resonance (EPR), transmission electron microscopy. X-ray photoelectron and Raman spectroscopy. It was found that long time oxidation perforated and fragmented sintered CNTs and increased the oxygen content in the material causing an increase in the number of paramagnetic centers. Two components in the absorption EPR spectra were distinguished: A narrow and a broad line with different g-factors, which testifies the different surrounding of paramagnetic centers associated with the lines. The results are of great importance for understanding the mechanism of nanotubes oxidation and development new types of catalysts, electromagnetic shielding materials and absorbents.

Automated summary

This study investigated the local electronic structure of carbon nanotubes (CNTs) consolidated by spark plasma sintering and further oxidized by nitric acid. It was found that oxidation increased the oxygen content, perforated the CNTs, and increased the number of paramagnetic centers. The absorption EPR spectra showed two components with different g-factors, indicating different surroundings of the paramagnetic centers. These findings are important for understanding the oxidation mechanism of nanotubes and developing new materials.