Tuning the nature of nitrogen atoms in N-containing reduced graphene oxide

Sandoval, Stefania; Kumar, Nitesh; Oró‐Solé, Judith; Sundaresan, A.; Rao, C. N. R.; Fuertes, Amparo

doi:10.1016/j.carbon.2015.09.085

Cited by 66 publications

(59 citation statements)

References 44 publications

(53 reference statements)

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“…The UV/Vis spectrum of GO shows a characteristic maximum absorption peak at around 240 nm attributed to the π–π* transition of aromatic C−C bonds . In the modified‐GO hybrids with anionic boron clusters, this absorption band is redshifted about 15–30 nm when the supernatant liquid is analyzed, which confirms the chemical modification of GO . In the Cosane‐GO dispersions the band around 305 nm is characteristic of the cosane anion .…”

Section: Methodsmentioning

confidence: 71%

Highly Dispersible and Stable Anionic Boron Cluster–Graphene Oxide Nanohybrids

Cabrera‐González

Cabana

Ballesteros

et al. 2016

Chemistry A European J

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An efficient process to produce boron cluster-graphene oxide nanohybrids that are highly dispersible in water and organic solvents is established for the first time. Dispersions of these nanohybrid materials in water were extraordinarily stable after one month. Characterization of hybrids after grafting of appropriate cobaltabisdicarbollide and closo-dodecaborate derivatives onto the surface of graphene oxide (GO) was done by FT-IR, XPS, and UV/Vis. Thermogravimetric analysis (TGA) clearly shows a higher thermal stability for the modified-GO nanohybrids compared to the parent GO. Of particular note, elemental mapping by energy-filtered transmission electron microscopy (EFTEM) reveals that a uniform decoration of the graphene oxide surface with the boron clusters is achieved under the reported conditions. Therefore, the resulting nanohybrid systems show exceptional physico-chemical and thermal properties, paving the way for an enhanced processability and further expanding the range of application for graphene-based materials.

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Section: Methodsmentioning

confidence: 71%

Highly Dispersible and Stable Anionic Boron Cluster–Graphene Oxide Nanohybrids

Cabrera‐González

Cabana

Ballesteros

et al. 2016

Chemistry A European J

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“…In all the irradiated samples a red shift of the π–π* peak can be observed. This shift can be directly related to the level of reduction of the material and the nitrogen content . The change of peak position could thus be ascribed to partial restoration of electronic conjugation of GO generally produced by the elimination of the oxygen based functionalities (defects) present into the lattice .…”

Section: Resultsmentioning

confidence: 99%

“…In the present study, the presence of graphitic N suggests that structural N is introduced into the sample by laser/NH 3 treatments (Figures S2–S4). Additional evidence of doping arises from the observed agglomeration of the material upon irradiation, since the presence of N‐bearing aliphatic functionalities would result in highly dispersible samples . The doping process is produced via the interaction of the oxygen based moieties on the GO surface and the nitrogen source.…”

Section: Resultsmentioning

confidence: 99%

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Nanosecond Laser‐Assisted Nitrogen Doping of Graphene Oxide Dispersions

et al. 2017

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N-doped reduced graphene oxide (RGO) has been prepared in bulk form by laser irradiation of graphene oxide (GO) dispersed in an aqueous solution of ammonia. A pulsed Nd:YAG laser with emission wavelengths in the infrared (IR) 1064 nm, visible (Vis) 532 nm, and ultraviolet (UV) 266 nm spectral regions was employed for the preparation of the N-doped RGO samples. Regardless of the laser energy employed, the resulting material presents a higher fraction of pyrrolic nitrogen compared to nitrogen atoms in pyridinic and graphitic coordination. Noticeably, whereas increasing the laser fluence of UV and Vis wavelengths results in an increase in the total amount of nitrogen, up to 4.9 at. % (UV wavelength at 60 mJ cm fluence), the opposite trend is observed when the GO is irradiated in ammonia solution through IR processing. The proposed laser-based methodology allows the bulk synthesis of N-doped reduced graphene oxide in a simple, fast, and cost efficient manner.

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“…rGO was prepared by chemical reduction of GO [18] (synthesized by a modified Hummers´ method) [19] with hydrazine (see the Supporting Information). Thermogravimetric analyses (TGA) under flowing air were performed to confirm the reduction of GO.…”

Section: Synthesis and Characterization Of The Rgo@ptm Materialsmentioning

confidence: 99%

Synergistic Exploitation of the Superoxide Scavenger Properties of Reduced Graphene Oxide and a Trityl Organic Radical for the Impedimetric Sensing of Xanthine

Seber

Muñoz

Sandoval

et al. 2017

Adv Materials Inter

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rapidness, sensitivity, specificity, low cost, and automated methodologies. [4][5][6] The enzyme XO is a type of liver enzyme that catalyzes the univalent and divalent reduction of ground state oxygen to generate both superoxide anion radical O 2•− and hydrogen peroxide (H 2 O 2 ) via a one-electron and a two-electron reduction, respectively, resulting in the oxidation of hypoxanthine to X and then X to uric acid. [7] To date, the determination of X through an electrochemical device is mainly focused on immobilizing XO onto different films and membranes, where the H 2 O 2 resulting from the X/XO enzymatic system is amperometrically (bio)sensed. [3] However, these XO-based amperometric biosensors have few drawbacks, such as poor stability and slow electron transfer, yielding to determine X at µm levels. More recently, (bio)sensors based on metal or metal oxide nanoparticles mixed with carbon-based nanomaterials, including graphene related nanomaterials, have shown some electrocatalytic properties toward X determination but the limit of detection (LOD) was not improved significantly. [1,3] In this regard, graphene and graphene-based materials, such as graphene oxide (GO) and reduced graphene oxide (rGO), have shown enhanced electrochemical and electrocatalytic activity over conventional carbon materials (e.g., graphite or carbon nanotubes) for (bio)sensing purposes. [8][9][10][11][12] While graphene is an electrical conductor, GO can be electrically insulating, being its reduction to rGO a simple strategy to partially restore the π electron network of graphene and hence its electrical conductivity. Among several novel applications, [13] graphene-based materials have shown to possess antioxidant activity, i.e., they can act as radical scavengers against various reactive oxygen species (ROS), especially for hydroxyl radicals or superoxides. [14,15] These studies showed that the primary active sites are associated with the pristine sp 2 -carbon network, rather than oxygen-containing functional groups.Perchlorotriphenylmethyl (PTM) radicals are persistent organic free radicals from the trityl radical family, the chemical and thermal stability of which rely on the full steric blockage of the central carbon atom by the ortho chlorine atoms. [16] Previous to our work, water soluble PTM derivative was demonstrated to react with high sensitivity and specificity with the superoxide generated from the X/XO enzymatic system. The This work is based on synergetically exploiting the activity of graphene-based materials and trityl free radicals to sense xanthine (X) by their combined scavenging properties for superoxide anion radical (O 2 •−). For this, reduced graphene oxide (rGO) and rGO covalently functionalized with a perchlorotriphenylmethyl (PTM) radical derivative (rGO@PTM) are synthesized, characterized, and casted on an electrode surface to achieve a highly sensitive electrochemical recognition platform for xanthine determination. The electrochemical analysis is based on impedimetrically monitoring a radicalinvolved react...

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Tuning the nature of nitrogen atoms in N-containing reduced graphene oxide

Abstract: Tuning the nature of nitrogen atoms in N-containing reduced graphene oxide, Carbon (2015),

Cited by 66 publications

References 44 publications

Highly Dispersible and Stable Anionic Boron Cluster–Graphene Oxide Nanohybrids

Highly Dispersible and Stable Anionic Boron Cluster–Graphene Oxide Nanohybrids

Nanosecond Laser‐Assisted Nitrogen Doping of Graphene Oxide Dispersions

Synergistic Exploitation of the Superoxide Scavenger Properties of Reduced Graphene Oxide and a Trityl Organic Radical for the Impedimetric Sensing of Xanthine

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