Designed nitrogen doping of few-layer graphene functionalized by selective oxygenic groups

Abstract

Few-layer nitrogen doped graphene was synthesized originating from graphene oxide functionalized by selective oxygenic functional groups (hydroxyl, carbonyl, carboxyl etc.) under hydrothermal conditions, respectively. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) observation evidenced few-layer feature of the graphene oxide. X-ray diffraction (XRD) pattern confirmed phase structure of the graphene oxide and reduced graphene oxide. Nitrogen doping content and bonding configuration of the graphene was determined by X-ray photoelectron spectroscopy (XPS), which indicated that different oxygenic functional groups were evidently different in affecting the nitrogen doping process. Compared with other oxygenic groups, carboxyl group played a crucial role in the initial stage of nitrogen doping while hydroxyls exhibited more evident contribution to the doping process in the late stage of the reaction. Formation of graphitic-like nitrogen species was controlled by a synergistic effect of the involved oxygenic groups (e.g., -COOH, -OH, C-O-C, etc.). The doping mechanism of nitrogen in the graphene was scrutinized. The research in this work may not only contribute to the fundamental understandings of nitrogen doping within graphene but promote the development of producing novel graphene-based devices with designed surface functionalization.

Heteroatom-doped graphene and its application as a counter electrode in dye-sensitized solar cells

“…N‐doped graphene tends to have different layer distribution which is highly dependent on the synthesis parameters, especially temperature. Many researchers have reported that doping of GO at higher temperature results in few‐layer N‐doped graphene . However, Ying et al reported few‐layer N‐doped graphene synthesized at a lower temperature of 180°C.…”

“…Many researchers have reported that doping of GO at higher temperature results in few‐layer N‐doped graphene . However, Ying et al reported few‐layer N‐doped graphene synthesized at a lower temperature of 180°C. N‐doped graphene is not only highly dependent on growth temperature but also on the synthetic mass ratio of nitrogen source and GO.…”

Carboxylated graphene oxide promoted axonal guidance growth by activating Netrin‐1/deleted in colorectal cancer signaling in rat primary cultured cortical neurons

“…GO functionalization with the carbonyl chloride group has become important because it permits a reaction with nucleophilic reagents, for example, amines and alcohols, forming amide or ester groups covalently bound to the GO core. Chen et al synthesized a hydrophilic and carboxylated graphene oxide (GO‐COOH) in situ …”

“…Chen et al synthesized a hydrophilic and carboxylated graphene oxide (GO-COOH) in situ. 6 Biomedical application of graphene-based materials have grown at a rapid pace and exhibited immense potential for future applications. 7 While intrinsic characteristics of graphene, especially its transparency, flexibility, and high conductivity make this material particularly attractive for neuroscience applications, as it represents a promising tool for neuronal implants and bio devices for neuro-oncology and neurodegeneration research.…”

“…However, GO-COOH has higher solubility and conductivity. Cell viability was assessed using CCK-8 assays and fluorescein diacetate after GO and GO-COOH treatment (0,1,2,4,5,6,8,10,12,14,16,18,20, 50, and 100 mg/mL). There are significant increases of cell viability and axonal growth after GO (2 and 4 lg/mL) and GO-COOH treatment (2 and 4 lg/mL).…”