METHANE CONVERSION TO GRAPHENE OXIDE (GO) USING A MICROWAVE SURFATRON PLASMA-TORCH REACTOR IN ATMOSPHERIC PRESSURE

• Main Author: Fadhil Rizki, Muhammad
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/55112
• Institution: Institut Teknologi Bandung

Graphene oxide (GO) is an allotropic carbon material with an exotic structure. GO can be produced through the conversion of natural gas, i.e., methane, using plasma technology. The abundance of coal-bed methane (CBM) in Indonesia has a more significant potential for further processing to produce GO with higher economic value. The data recorded in the Ministry of Energy and Mineral Resources of the Republic of Indonesia mentioned that the methane deposit as CBM in Indonesia is very abundant, reaching 453.3 TCF. In this study, microwave plasma technology was chosen for the methane conversion to GO. A simple microwave plasma reactor was fabricated based on the modified domestic microwave oven by adding a tapered waveguide. The fabricated reactor produced a continuous atmospheric plasma consisting of methane and argon activated species, confirmed by the optical emission spectroscopy measurements. We also observed a correlation between the ignitor electrode's work function, which has different alloy composition, and the intensity of plasma optical emissions. This correlation was further confirmed by the abundance of H? (n = 3 ? 2) transition that increases as the ignitor electrode’s work function decreases. This result shows that the plasma-forming reactivity during the feed gas ionization process can be achieved easier when the ignitor electrode’s work function is low. The identification of the allotropic carbon material formed in this process was carried out using vibrational spectroscopy techniques. The presence of the GO was confirmed based on the identical Raman and IR vibrational modes on the spectra with respect to the literature. The Raman spectra confirmed the formation of GO material by the presence of G (1585 cm-1), D (1350 cm-1), 2D (2700 cm-1) bands, which are assigned as the sp2 bonds (E2g), breathing (A1g), and 2nd-order overtone (A1g) vibrational modes of the GO structure. The FTIR spectra support the Raman spectroscopy results, showing the presence of OH (3443 cm-1), C = C (1642 cm-1), C-O-C (1018 cm-1), and C = O (1098 cm-1) vibrational modes. WO3, a tungsten ignitor electrode’s oxidation product, is also observed as a vibrational mode at 802 cm-1 in the FTIR spectra.