Reduced Graphene Oxide: Effect of Reduction on Electrical Conductivity

Abstract

In this study, the effect of reduction on the electrical conductivity of Graphene Oxide (GO) is investigated. The aim of this fabrication was to render electromagnetic interference (EMI) shielding to thin polymer films using GO as fillers. The electrical conductivity was determined using the four-probe method and shielding effectiveness was theoretically determined using the experimentally obtained conductivity values. The initial oxidation of graphite was performed using Hummers' method and the oxidized GO was dispersed in water for further exfoliation by ultrasonication. Thin films of sonicated GO dispersions were solution casted and dried in a convection oven at 50 • C overnight. The dried films were treated with 48% hydrobromic acid (HBr), 95% hydrochloric acid (HCl) or 66% hydroiodic acid (HI) for 2 h, 24 h or 48 h. A partial factorial design of experiments based on Taguchi method was used to identify the best reducing agent to obtain maximum electrical conductivity in the partially reduced GO films. The experimental analysis indicates that the electrical resistivity of GO is highly dependent on the type of acid treatment and the samples treated with HI acid exhibited lowest resistivity of~0.003 Ω·cm. The drop in resistivity value after chemical reduction was of the order of 10,000 times, and range obtained in this work is among the lowest reported so far. The theoretical EMI shielding of the reduced GO film provided a shielding effectiveness of 5.06 dB at 12 GHz.

Graphene-Oxide-Based Electrochemical Sensors for the Sensitive Detection of Pharmaceutical Drug Naproxen

“…The only outlier was the F-GO/GCE, as it accounted for only 28.33% of the GO detection signal. However, it is known that fluorine doping completely disrupts the sp2 carbon ring structure, thus further decreasing the conductivity of GO [13]. In comparison, nitrogen or boron-doped graphene oxide typically possessed heteroatoms that replaced the carbon atoms, and became incorporated within the ring structures [39].…”

“…Hendawy et al reported nanomaterial-based carbon paste electrodes for the detection of naproxen and its degradation product [10]. Over the last decade, the exploration of graphene and graphene-based nanomaterials has garnered tremendous attention due to their unique electronic, structural, and physical attributes [11][12][13][14]. The structure of graphene includes a single layer of sp2-hybridized hexagonal lattices that form honeycomb structures with a high surface area, which are both electronically and thermally conductive [9].…”

“…The structure of graphene includes a single layer of sp2-hybridized hexagonal lattices that form honeycomb structures with a high surface area, which are both electronically and thermally conductive [9]. Graphene oxide (GO) synthesized from graphite contains abundant oxygen functional groups, including hydroxyl, carboxylic acids, and epoxy groups, which demonstrate good catalytic activities, particularly for the oxidation of organic molecules [12][13][14][15]. However, the presence of oxygen groups disrupts the sp2 bonds of carbon rings, thereby lowering conductivity.…”

Flexible Foil of Hybrid TaS2/Organic Superlattice: Fabrication and Electrical Properties

“…As shown in Figure a, the electrical conductivity of the as‐prepared 22 μm thick TaS 2 HA 0.371 NMF 0.135 foil was measured to be 1173.8 S cm −1 , which is among the best values in solution‐based graphene and IGAs, such as graphene films made by vacuum filtration (≈(0.8–3) × 10 2 S cm −1 ), inkjet printing (2.5 × 10 2 S cm −1 ), and casting ((3.3–5.4) × 10 2 S cm −1 ), and a conducting hydric TiS 2 foil synthesized by hydrogen intercalation (6.8 × 10 2 S cm −1 ) . Thus, the as‐prepared hybrid foil shows great potential to be incorporated into flexible electrodes of high conductivity.…”

“…The foil shows excellent mechanical stability and chemical stability in air. A high electrical conductivity and high electromagnetic interference (EMI) shielding effectiveness (SE) values were observed, which are among the best values for solution‐based thin‐film graphene or IGAs . The solution‐based strategy used to fabricate high‐quality, large‐area flexible foil of TMDC/organic superlattices could provide new opportunities for electronic devices that rely on the abnormal properties of 2D materials.…”