Journal Article

Treatment of Multi-Walled Carbon Nanotubes with Dichromic Acid: Oxidation and Appearance of Intercalation

Maksimovskiy, Evgene A., Golovakhin, Valeriy, Ishchenko, Arcady V., Bannov, Alexander G., Ukhina, Arina V., Novgorodtseva, Oksana N., Kim, Ekaterina Yu

2023

Overview

This work is dedicated to the study of the treatment of multi-walled carbon nanotubes (MWCNTs) with dichromic acid. The dichromic acid was formed by dissolving different concentrations of CrO3 in water. The effect of the concentration of dichromic acid on the change in texture characteristics, elemental composition, defectiveness, graphitization degree, and surface chemistry of MWCNTs was investigated using various analytical techniques, such as transmission electron microscopy, energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, and X-ray photoelectron spectroscopy (XPS). Testing of MWCNTs as electrodes for supercapacitors in 3.5 M H2SO4 solution was carried out using cyclic voltammetry. A decrease in the average diameter of CNTs after treatment was found. The EDX and XPS showed that the oxygen content on the surface of MWCNTs increased after treatment with dichromic acid. The formation of Cr2O3 after treatment with dichromic acid was detected by XPS. High angle annular dark field scanning transmission electron microscopy was used to confirm the intercalation of the chromium-containing compound between graphene layers of MWCNTs after treatment with dichromic acid. It was found that two different types of MWCNTs showed diverse behavior after treatment. The highest specific capacitance of the MWCNTs after treatment was 141 F g−1 (at 2 mV s−1) compared to 0.3 F g−1 for the untreated sample.

• Publisher: MDPI AG,MDPI
• Subject: Capacitance / Carbon / carbon nanomaterials / carbon nanotubes / Chemical composition / chemical functionalization / Chromium / Chromium compounds / Chromium trioxide / Decomposition / dichromic acid / Electrodes / Energy dispersive X ray spectroscopy / Fourier transforms / functionalization / Graphene / Graphite / Graphitization / Infrared spectroscopy / Intercalation / Multi wall carbon nanotubes / MWCNTs / Nanomaterials / Nanotechnology / Nanotubes / Oxidation / Oxygen content / Photoelectron spectroscopy / Photoelectrons / Radiation / Scanning transmission electron microscopy / Sensors / Spectrum analysis / Sulfuric acid / Surface chemistry / Transmission electron microscopy / Voltammetry / X ray photoelectron spectroscopy / X-ray diffraction / X-ray spectroscopy