Synthesis and Application of Network Single-layered Graphene/Ag Hybrids

• Main Authors: Wei-Chen Lin, 林韋辰
• Other Authors: Jih-Mirn Jehng
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/rvg96n

碩士 === 國立中興大學 === 化學工程學系所 === 101 === Exfoliated graphene sheets (XGS) were prepared from graphite oxide (GO) via a green chemistry route. Dehydration of GO is the main mechanism for the reduction and transformation of C-C bonds from sp3 to sp2. The oxygen-containing groups of GO would decompose to produce gases (H2O) and volatile substances (HCl) during the thermal treatment process. For a successful exfoliation process, the pressure generated from the evolved gases that causes rapid expansion would exceed Van der Waals forces holding GO sheets together. Different contents of the oxygen-containing moieties on the graphite oxide and graphene surface would bring about various grafting ratios of the intended compounds. First, 4-isocyanato-4’(3,3-dimethyl-2,4-dioxo- azetidino) diphenyl -methane (IDD) reacted with carboxylic acid or hydroxy functional group on the graphite oxide and graphene surface to provide a reactive site. Subsequently, a polyetheramine, JEFFAMINE® ED-2003 was reacted with the dione functional group leaving the other pendant primary amine as the grafting site for an intended dendron. The content of functional groups and the size of grafting compounds play an important role in keeping graphene and graphene oxide from aggregation. Via the thermal treatment process, XGS comprised randomly ordered graphitic platelets in a corrugated structure. As the IDD molecules reacted with the reduced graphene sheets, the spacings of graphene single-layers could be well maintained. As for GO, the covalent attachment of JEFFAMINE ED-2003 was required to achieve exfoliation. We demonstrated that the respective grafting of relatively low molecular weight JEFFAMINE ED-2003 to GO, and IDD to the reduced graphene was sufficient to prevent single-layers from aggregation. Due to poor electronic transfer ability of the polymers attached to the exfoliated graphene hybrids, silver nanoparticles were adsorbed on the grafted polymers to increase the conductivity. The work functions of XGS/Ag nanohybrids were measured to be 4.72 – 4.76 eV. The large work functions suggest that these XGS/Ag nanohybrids can potentially be applied as electrode materials for optoelectronic devices.