Capsule-embedded reduced graphene oxide: synthesis, mechanism and electrical properties

Abstract

We report the synthesis of capsule-embedded reduced graphene oxide (rGO) by photocatalytic reduction in the presence of peanut shaped a-Fe 2 O 3 particles under visible light. This process is able to produce highly stabilized water dispersible rGO without the help of a stabilizer, which is suitable to make thin films on a glass substrate by the drop casting method. In addition, the evolution of the morphology with different visible light exposure times ranging from 5 to 120 minutes reveals that the catalyst leads to transformation of a few rGO sheets into capsules via a core-shell structure. These capsules are stable on the rGO sheet at a vacuum of 10 À9 Torr, but unstable under vacuum annealing at 400 C and 10 À5 Torr that created impressions on the rGO film. The bandgap of the capsule-embedded rGO decreases nonlinearly with the visible light exposure time; from 2.47 eV at 5 min to 1.73 eV at 120 min. The vacuum annealed rGO films on glass substrates show an electrical conductivity of 2000 S m À1 at 300 K and the conduction is dominated by two-dimensional variable range hopping. The formation of capsules is described based on electrostatic interactions in association with the dipole force of the monodispersed peanut shaped a-Fe 2 O 3 particles, whereas, the bandgap opening and high conductivity are attributed to the residual oxygen functional groups such as carbonyl (>C]O) and epoxy (C-O-C) on the rGO, in addition to the modulated surface morphology.

High efficiency solar desalination and dye retention of plasmonic/reduced graphene oxide based copper oxide nanocomposites

“…46 For UV-vis spectrum of CuO-rGO nanocomposites, it is observed that the peak in GO spectrum at 230 nm is shied to 256 nm due to the reduction GO sheet and the characteristic peak of CuO nanoparticles appeared at 375 nm. 46,47 Also, the characteristics peak of AgNPs appeared at 400 nm in the spectrum of Ag-rGO and Ag/CuO-rGO nanocomposites which conrms the presence of AgNPs on GO surface. 48 The structures and phase composition of all prepared samples were examined by using XRD measurements and the corresponding pattern is shown in Fig.…”

Synthesis and characterization of sulfophenyl-functionalized reduced graphene oxide sheets

“…The optical band gap (E g ) of RGO and SRGO were estimated using the Tauc-David Mott equation (eqn (1)). [21][22][23][24][25]…”

High Performance of Covalently Grafting onto Collagen in The Presence of Graphene Oxide

“…To identify the GO content, UV-Vis spectroscopic studies were performed, Figure 3 . It is inferred that the presence of GO contents is identified through the optical absorption of GO dominated by the π–π stacking at about the more intense peak of 230 nm [ 33 , 34 ]. The π–π stacking peak on film samples with GO contents was recorded with a blue shift when compared with GO at 212, 213, 216, and 220 nm for F2-16, F2-8, F1-8, and F1-16, respectively.…”