Continuous Graphene-like Layers Formed on Copper Substrates by Graphene Oxide Self-Assembly and Reduction

Abstract

Copper substrates are known to be able to assist the spontaneous assembly and reduction of graphene oxide in liquid medium, but very scarce information is known about the involved mechanism. This study analyzes a number of relevant factors affecting this process: copper substrate geometry, concentration of graphene oxide dispersion, reaction time, presence of ligands in the reaction medium, and reaction temperature. Characterization techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and attenuated total reflectance−Fourier transformed infrared (ATR− FTIR) have been applied to characterize the reduced graphene oxide (rGO) coating on copper. In the light of the obtained results, a reaction mechanism is proposed. Open-area copper substrates favor not only the complete coating of the copper surface but also the formation of self-standing continuous rGO films on open areas. Removal of copper ions, which are originated in the redox process, takes place by means of Cu 2+ -rich subsurface streams flowing underneath the rGO layers toward the aqueous medium. This simple and cost-effective procedure paves the way to design graphenelike bidimensional layered structures from the copper-induced self-organization of GO platelets as building blocks.

Patterning Large Free-Standing Reduced Graphene Oxide Films Assisted by Open-Area Copper Substrates for Graphene Drums

“…Depending on the conditions at the interface (pH, temperature, presence of ligands, etc. ), copper ions may diffuse toward the aqueous medium through channels usually formed in the interphase between the copper surface and the rGO coating (Figure b.2), as elevated wrinkles, or are sometimes accumulated below the rGO film and precipitate as Cu 2 O (Figure b.3) . These ion channels, which are easily observed to plow through the copper strands toward the open areas, are more clearly presented in images a.2 (see details in the inset image) and b.2 in Figure .…”

“…Open-area copper surfaces have been shown to be able to assist the growth of rGO films on its interstitial openings. , Reduced graphene oxide films are easily grown on this kind of substrates. The surface of the copper grid strands assists the adsorption of the GO flakes on it, promotes their reduction, and favors their assembly with other flakes in their vicinity.…”

Specific capacitance of graphene oxide–metal interfaces at different deoxygenation levels

“…GO reduction by metallic surfaces at room temperature has been reported by various groups. [50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68] Hence, at rst glance, the presence of metal oxide particles at a GO/M interface would appear normal. However, a rough estimation of the observed masses of the interface-grown oxide/hydroxide layers, surprisingly, leads to amounts much larger than those calculated by assuming total oxygen transfer from the deposited GO to the metallic surface; e.g.…”

“…Research on GO/MO interfaces has produced sporadic results and singular observations. Self-assembly and spontaneous reduction of GO on metallic surfaces have also been reported, and the observed phenomena have been described by considering the electron transport and the electrostatic interactions taking place between GO and M. [50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68] The advantages of these phenomena have been utilized for the actuation of niche applications such as the fabrication of batteries, thermal energy absorbers, actuators, transparent conductive lms, electrodes for lithium ion batteries, and large area graphene synthesis. [62][63][64][65][66][67][68] GO/M interfaces have also been used in different electronic devices.…”

Enhanced performance of high‐temperature proton exchange membrane by introducing 1,2, 4‐triazole‐ functionalized graphene oxide into polybenzimidazole

“…RESULTS AND DISCUSSION3.1 | Structural characterizationFT-IR spectroscopy was used to study the functional group absorption on the expanded graphite, GO, and NGO. (Figure1) In GO, the absorption peaks at 3450, 1724, and 1619 cm À1 belong to O H, C═O, and C═C vibrational bands,24,25 whereas the peaks at 1168 and 1035 cm À1 represent C O epoxy and C OH stretching mode of the sp 2 skeletal network, respectively, proving the successful synthesis of GO. In the IR spectrum of NGO, the peak at 2887 cm À1 is assignable to the stretching vibrations of N H in the 1,2,4-triazole molecule.…”