Highly Exfoliated Graphene Oxide with Enhanced Carbonyl Content and Facile Amine Functionalization for Biomedical Applications

Abstract

A reroute process of Hummers' method was carried out to reduce some steps in the synthesis of highly exfoliated graphene oxide (HEGO). Using pure KMnO 4 and NaNO 3 in concentrated H 2 SO 4 , HEGO was successfully prepared to contain extra carbonyl functional groups that helped stabilize the GO layer exfoliation. The oxidation reached its completion by one straight temperature level at 35 °C within a short reaction time (4 h). The obtained HEGO was observed to be highly dispersible through atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscope (TEM). The X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) were also used to reveal the actual structure of HEGO and its analogues, which were formed from the reaction with aliphatic amines such as L-arginine (Arg) and β-alanine (Ala) as well as one aromatic amine, aniline (Ani). The results showed an interaction based on covalent bonding. The reduction reaction with L-ascorbic acid under basic conditions at 95 °C for 24 h was also performed. These facile functionalization and reduction process indicate the possible biomolecular adsorption.

Single-Layer Graphene Oxide-Amino-β-Cyclodextrin/Black Phosphorus Nanosheet Composites for Recognition of Tyrosine Enantiomers

“…The TGA curves of NH 2 -βCD and SGO-NH 2 -βCD were measured in a temperature range of 35–600 °C under an argon atmosphere at a heating rate of 10 °C min –1 . As shown in Figure S3B, SGO-NH 2 -βCD (curve b) shows weight losses of 3.7 and 18.8 wt % at temperature ranges of 35–120 and 120–240 °C, which correspond to the removal of physically adsorbed water and the decomposition of oxygen-containing functional groups, respectively . The weight loss of SGO-NH 2 -βCD in a temperature range of 240–500 °C is 10 wt %, which could be attributed to the decomposition of the attached NH 2 -βCD in comparison with the TGA curve of pure NH 2 -βCD (curve a).…”

“…As shown in Figure S3B, SGO-NH 2 -βCD (curve b) shows weight losses of 3.7 and 18.8 wt % at temperature ranges of 35−120 and 120−240 °C, which correspond to the removal of physically adsorbed water and the decomposition of oxygencontaining functional groups, respectively. 44 The weight loss of SGO-NH 2 -βCD in a temperature range of 240−500 °C is 10 wt %, which could be attributed to the decomposition of the attached NH 2 -βCD in comparison with the TGA curve of pure NH 2 -βCD (curve a). Based on the above analyses, we can confirm that NH 2 -βCD was successfully grafted onto SGO through the amidation reaction.…”

Stimulus‐Responsive Tubular Conjugated Polymer 2D Nanosheets

“…Correspondingly, C1s of MCPDA-EDEA (Figure S10b) exhibit the five peaks at binding energies of 284.7, 285.7, 286.5, 288.5, 289.1 eV and correspond to the CÀ C, CÀ N, CÀ O, NÀ C=O, and OÀ C=O photoelectrons. [66][67][68] Likewise, the C1s of the mixture showed the six characteristic peaks (Figure S10c). Upon forming the mixture, the relative fraction of the CÀ N peak increases compared to the expected one simply calculated using the composition portion and C1s deconvoluted spectrum (8 % vs 4 % = 0.45 × 0.09).…”

“…The C1s spectrum of GO (Figure S10a) is deconvoluted into four characteristic peaks at binding energy values of 284.7, 286.6, 287.7, and 289.1 eV, which correlate to C−C, C−O, C=O, and O‐C=O, respectively. Correspondingly, C1s of MCPDA‐EDEA (Figure S10b) exhibit the five peaks at binding energies of 284.7, 285.7, 286.5, 288.5, 289.1 eV and correspond to the C−C, C−N, C−O, N−C=O, and O−C=O photoelectrons [66–68] . Likewise, the C1s of the mixture showed the six characteristic peaks (Figure S10c).…”

Insight into the Recent Advances in Sustainable Biodiesel Production by Catalytic Conversion of Vegetable Oils: Current Trends, Challenges, and Prospects

“…Synthesis of GO. This figure was reprinted with permission from ref . Copyright 2020 American Chemical Society.…”