MODIFIED GREEN PROCESS OF REDUCED GRAPHENE OXIDE (RGO) SYNTHESIS FOR IMPROVING ELECTRICAL CONDUCTIVITY

• Main Author: HIKMAH (NIM: 20215044), UTIYA
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/24603
• Institution: Institut Teknologi Bandung

Graphene is a 2D material with a hexagonal lattice and a thickness of one atom. It <br /> <br /> <br /> has interesting properties such as high thermal conductivity, high surface area, high <br /> <br /> <br /> electrical conductivity, very strong, high transparency and flexible. Therefore, it <br /> <br /> <br /> gives a promising application such as for electronic devices and catalysts. One of <br /> <br /> <br /> facile synthesis method to produce graphene is chemical synthesis by reducing the <br /> <br /> <br /> graphene oxide (GO) to form Reduced Graphene Oxide (rGO). There are four steps <br /> <br /> <br /> in the chemical process of rGO, i,e. (i) oxidation process, by dissolving graphite in <br /> <br /> <br /> acid mixture solution and adding KMnO4 as an oxidizing agent, (ii) exfoliation <br /> <br /> <br /> process to produce graphene oxide, (ii) reduction process by adding hydrazine <br /> <br /> <br /> hydrate as reducing agents, (iv) heating with microwaves to accelerate and to <br /> <br /> <br /> increase the efficiency of the reduction process. In this study, we combine the <br /> <br /> <br /> modified Hummer and Marcano method, by using a mixed acid solution of sulfuric <br /> <br /> <br /> acid and phosphoric acid (9:1). Then, hydrazine hydrate was used as a reducing <br /> <br /> <br /> agent under microwave irradiation under normal atmosphere and inert conditions. <br /> <br /> <br /> Various microwave radiation levels (high, medium and low) and irradiation times <br /> <br /> <br /> (1, 2, 3, 4, and 5 min) were performed. The highest conductivity of 18.10 S/cm was <br /> <br /> <br /> obtained. A preliminary study of another reducing agent such as L-ascorbic acid <br /> <br /> <br /> (LAA) was used as the more environmentally friendly reducing agent, which <br /> <br /> <br /> resulted in electrical conductivity of 12.02 S/cm. From the XRD (X-ray Diffraction) <br /> <br /> <br /> results, we concluded that the graphene oxide has been successfully reduced. <br /> <br /> <br /> Raman result showed ID/IG ratio (indicating disorder level) of rGO was 1.09 and <br /> <br /> <br /> 1.05 for rGO-LAA. After the annealing process at 300 °C for 30 minutes, the <br /> <br /> <br /> electrical conductivity of rGO increases up to 23.26 S/cm and 16.19 S/cm for rGOLAA.