Study of simultaneous reduction and nitrogen doping of graphene oxide Langmuir–Blodgett monolayer sheets by ammonia plasma treatment

Abstract

Graphene oxide (GO) monolayer sheets, transferred onto Si by the Langmuir-Blodgett technique, were subjected to ammonia plasma treatment at room temperature with the objective of simultaneous reduction and doping. Scanning electron microscopy and atomic force microscopy studies show that plasma treatment at a relatively low power (∼10 W) for up to 15 min does not affect the morphological stability and monolayer character of GO sheets. X-ray photoelectron spectroscopy has been used to study de-oxygenation of GO monolayers and the incorporation of nitrogen in graphitic-N, pyrrolic-N and pyridinic-N forms due to the plasma treatment. The corresponding changes in the valence band electronic structure, density of states at the Fermi level and work function have been investigated by ultraviolet photoelectron spectroscopy. These studies, supported by Raman spectroscopy and electrical conductivity measurements, have shown that a short duration plasma treatment of up to 5 min results in an increase of sp²-C content along with a substantial incorporation of the graphitic-N form, leading to the formation of n-type reduced GO. Prolonged plasma treatment for longer durations results in a decrease of electrical conductivity, which is accompanied by a substantial decrease of sp²-C and an increase in defects and disorder, primarily attributed to the increase in pyridinic-N content.

Efficient degradation of Acid Orange 7 by persulfate activated with a novel developed carbon‐based MnFe2O4 composite catalyst

“…The spectral peak at 284.7 eV corresponded to carbon atoms with sp 2 hybridization . The spectral peaks at 285.5, 286.6 and 288.1 eV were assigned to CC, CO and OCO respectively . As seen in Fig.…”

“…1,49 The spectral peaks at 285.5, 286.6 and 288.1 eV were assigned to C-C, C O and O C-O respectively. 49,50 As seen in Fig. 2d, the high-resolution XPS spectrum of Fe 2p showed peaks at 711.2 and 725.1 eV for the fresh sample, coincident with Fe 2p 3/2 and Fe 2p 1/2 of Fe 3+ respectively.…”

Efficient Gelation of Graphene Oxide Aqueous Dispersion Induced by Sonication‐Promoted Leuckart Reaction

“…The Leuckart reaction is a reductive amination process in which aldehydes and ketones are transformed to amines in a multistep reaction that results in reduction of GO and simultaneous incorporation of nitrogen (Scheme ). When ammonium hydroxide is added to GO dispersion, NH 3 ⋅ H 2 O, in equilibrium with NH 4 OH, would transform edge carbonyl groups via a geminal hydroxyamine intermediate to imines in a reversible reaction.…”

Vertically aligned carbon nanotubes: production and applications for environmental sustainability

“…119 Considering plasma etching has been used to open VACNT caps as well as functionalize them, that technique, simultaneously generating graphitic vacancies and incorporating heteroatoms into these sites, might emerge as an alternative post-synthesis treatment approach to doping VACNTs under a N 2 or NH 3 gas environment. [120][121][122]…”