Covalently functionalized reduced graphene oxide by organically modified silica: a facile synthesis of electrically conducting black coatings on glass

Abstract

The fabrication of black and electrically conducting films on glass substrate derived from covalently functionalized reduced graphene oxide (FRGO) has been reported in this work. Graphene oxide (GO) was first prepared following the Hummers method and then functionalized using an organically modified silicon alkoxide, 3-glycidoxypropyltrimethoxysilane (GLYMO) in an ordered fashion. Catalyst (aluminium acetylacetonate) induced selective polymerization of the epoxy groups of GO and GLYMO was found to occur via the formation of ethereal (-C-O-C-) linkages. The formation of such linkages was confirmed by IR, Raman, TGA, X-Ray diffraction and TEM studies. Finally the functionalized graphene oxide (FGO) films were subjected to thermal reduction in an inert (N 2 ) atmosphere to obtain FRGO films. These hard FRGO films are electrically conducting and appeared as black coatings on glass. By varying the loading (20-30 wt%) of GO with the covalently bonded organically modified silica, the sheet resistance values can be tuned in a linear way from 0.8 Â 10 6 to 1.4 Â 10 3 U , À1 . The uniform current-voltage (I-V) characteristics of the films can be nicely correlated with the sheet resistance values.

Broadband optical limiting and nonlinear optical graphene oxide co-polymerization Ormosil glasses

“…These characterizations confirm that GOs have been prepared successfully. The FTIR spectra for GO and m-GO are shown in [28,34] indicate there exists conjugated structure, which is consistent with UV-vis spectra analysis and will improve nonlinear optical limiting properties [35]. As GO reacts with GLYMO, the epoxy C-O-C peak disappears and Si-C (1195 cm ) appear in spectrum, indicating GO is successfully modified by epoxy silane.…”

Role of the synthesis route on the properties of hybrid LDH-graphene as basic catalysts

“…It can be underlined that the catalytic activity dramatically increases from HT:rGO= 0.5:1 to 1:1 the catalyst with the lowest HT content being poorly active ( Figure 7A). During the reaction time of 480 min, in any case, the equilibrium conversion of 23.1% was reached 26 ; however, the catalytic performance showed by the calcined HT/rGO-xC80 catalysts with HT:rGO= 5:1, 10:1 and 20:1 was superior to that of the calcined bare HT (HTc) or other HT-derived mixed oxides reported previously 12,18,27,28 . Bare GO and rGO did not show any catalytic activity under the reaction conditions tested, which confirms that HT is the active phase of the reaction.…”

“…6A) of parent GO revealed peaks at 865 and 1038 cm -1 respectively attributed to the asymmetric bending and stretching of C-O-C vibrations, of the epoxy group. 18,19 The peak observed at ~1730 cm -1 is due to the C=O stretching from carboxylic acid and carbonyl moieties. 19 The peaks at ~3350 cm -1 (broad, with a shoulder at ~3165 cm -1 ) and 1624 cm -1 can be assigned to O-H stretching and H-O-H bending of adsorbed water molecules, respectively.…”

“…[18][19][20][21][22][23][24][25][26][27][28][29] A slighter influence of the drying and synthesis methods than at low HT loading on the hybrids' catalytic performance was observed, the catalysts submitted to freeze drying presenting the higher DAA yields. Of particular interest is the case of the hybrid catalyst prepared by coprecipitation and freeze dried (HT/rGO-10CFD) which showed the best performance with an average DAA amount of 102.7 mmol/gHTc; that is a specific activity (based on the weight of HT present in the hybrid catalyst) about 2.5 times higher than that of HTc.…”

Synergistic effects on the enhancement of thermal conductive properties of thermal greases

“…The peaks at 2974, 2933, and 1050 cm −1 are attributed to CH 3 , CH 2 , and CO stretching vibration, respectively. The GF shows the characteristic OH stretching vibrations at 3435 cm −1 , CO bending vibrations at 1559 cm −1 , and COH stretching vibrations at 1088 cm −1 , which indicates the existence of small amount of oxygen‐containing groups.…”