DEVELOPMENT NEW METHOD OF REDUCED GRAPHENE OXIDE (rGO) SYNTHESIS ON THE IMPROVEMENT OF ELECTRICAL PROPERTIES
Graphene is a two-dimensional (2D) carbon allotrope which is sp2 hybridized with a hexagonal lattice (honeycomb) and has a thickness of one atom. Graphene is a sheet of millions layer that form graphite. In recent years, graphene has be come the center of the world attention due to its suprame prope...
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| Format: | Theses |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/23070 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Graphene is a two-dimensional (2D) carbon allotrope which is sp2 hybridized with a hexagonal lattice (honeycomb) and has a thickness of one atom. Graphene is a sheet of millions layer that form graphite. In recent years, graphene has be come the center of the world attention due to its suprame properties, all of which make it highly attractive for numerous application. One methode to synthesize graphene is chemical synthesis process by reducing graphene oxide into reduced graphene oxide (rGO). However this synthesis process requires a relatively long <br />
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time, high temperatures and much harmful acids solution. On the other hand the graphene produced has low electrical conductivity. Therefore, it is necessary to modify the synthesis process methode. In this research we conduct a chemical synthesis process with a shorter time consuming, low temperature and slightly acid solution with microwave assisted. This modification has produced graphene with higher electrical conductivity. In addition, this synthesis process is relatively simpler, quicker, easier and safer. The result was a black color powder rGO. The characterization that used in this research are Tansform Fourier Infrared Spectroscopy (FT-IR), X-Ray Difrractometer (XRD), Spectroscopy Raman, Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS), 4 Point Probe, and Electrochemical Impedance Spectroscopy (EIS). The results of FTIR measurements show absorption peak graphene oxide (GO) appears on O-H, C=O and C-O. Absorption peak of rGO showed a reduction of oxygen functional group and GO has successfully transformed into rGO. From SEM characterization, we were able to observe the presence of graphene sheets. XRD characterization showed the highest diffraction peak (002) was at the 2θ ~24.5°, indicated that GO has been successfully reduced to rGO. Raman spectroscopy was used to confirm that graphene has been formed. The results showed the peak wavenumber of G band appears at position 1583.53 cm-1. The calculate number of graphene layers at G band was 1.14, which proved that graphene has been synthesized successfully. The D/G band intensity ratio (ID/IG) is importan to measure the disorder rate. The sample showed an ID/IG ratio of 1.15. Based on 4 point probe measurements, H3PO4 which used as a solvent additional acid in the synthesis process GO affect the electrical conductivity of the rGO. Where the optimum electrical conductivity is 15.422 S/cm at H2SO4/H3PO4 with ratio 7:3. Electrochemical performance of rGO as-synthesized was characterized using Electrochemical Impedance Spectroscopy (EIS) to determine the value of the charge transfer resistance (RCT). Charge transfer resistance value of the sample rGO synthesis without H3PO4 (10:0) is 46,57 Ω and samples rGO synthesis by use various H3PO4 rGO2, rGO3, rGO4, rGO5, rGO6) are respectively 2.10 Ω, 16.70 Ω, 23.00 Ω, 19.5 Ω, and 13.25 Ω. The characterization results showed that the addition of H3PO4 can improve the conductivity of charge transfer. Based on RCT values, the best result was achieved on rGO with ratio H2SO4/H3PO4 of 9:1. |
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