Time-dependent evolution of the nitrogen configurations in N-doped graphene films

Matsoso, Boitumelo J.; Ranganathan, K.; Mutuma, Bridget K.; Lerotholi, T. J.; Jones, Glenn; Coville, Neil J.

doi:10.1039/c6ra24094a

Cited by 138 publications

(109 citation statements)

References 54 publications

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“…However, an increase of the binding energy of C 1s peak in the XPS spectrum of N-graphene ( Figure 2b) is a sign of n-type doping. Another reason for the stiffening of the Raman peaks is the distortion of carbon bonds due to insertion of nitrogen atoms in the graphene lattice [66]. Pyrrolic N introduces the greatest distortion and this form prevails in the synthesis product as the N 1s spectrum shows (Figure 3a).…”

Section: Sample T S (K) Precursormentioning

confidence: 99%

Electronic Structure of Nitrogen- and Phosphorus-Doped Graphenes Grown by Chemical Vapor Deposition Method

et al. 2020

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Heteroatom doping is a widely used method for the modification of the electronic and chemical properties of graphene. A low-pressure chemical vapor deposition technique (CVD) is used here to grow pure, nitrogen-doped and phosphorous-doped few-layer graphene films from methane, acetonitrile and methane-phosphine mixture, respectively. The electronic structure of the films transferred onto SiO2/Si wafers by wet etching of copper substrates is studied by X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy using a synchrotron radiation source. Annealing in an ultra-high vacuum at ca. 773 K allows for the removal of impurities formed on the surface of films during the synthesis and transfer procedure and changes the chemical state of nitrogen in nitrogen-doped graphene. Core level XPS spectra detect a low n-type doping of graphene film when nitrogen or phosphorous atoms are incorporated in the lattice. The electrical sheet resistance increases in the order: graphene < P-graphene < N-graphene. This tendency is related to the density of defects evaluated from the ratio of intensities of Raman peaks, valence band XPS and NEXAFS spectroscopy data.

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Section: Sample T S (K) Precursormentioning

confidence: 99%

Electronic Structure of Nitrogen- and Phosphorus-Doped Graphenes Grown by Chemical Vapor Deposition Method

et al. 2020

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“…The N spectrum ( Figure SD2) of MS is related to one component of N: pyrrolic-N (399.8 eV). However, after activation, the CMMS shows two peaks corresponding to pyrrolic-N (399.8 eV) and quaternary-N (402.0eV) (Matsoso et al, 2016).…”

Section: Analysis For Ms and Cmms Before Biosorptionmentioning

confidence: 99%

Single, simultaneous and consecutive biosorption of Cr(VI) and Orange II onto chemically modified masau stones

Albadarin

Solomon

Kurniawan

et al. 2017

Journal of Environmental Management

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Novel and low cost chemically modified masau stone (CMMS) was investigated for its biosorption of an anionic azo dye, Orange II (OII), and toxic hexavalent chromium (Cr(VI)) from aqueous systems: individually, simultaneously and consecutively. XPS and FTIR analyses indicated the introduction of quaternary-Nitrogen to the CMMS surface after activation with epichlorohydrin (etherifying agent) and diethylenetriamine (crosslinking agent). The effects of pH, contact time and initial concentration (C), and loading order on mechanisms of biosorption/reduction of OII and Cr(VI) onto CMMS were examined in detail. Several analytical techniques were employed to characterise the physio-chemical properties of the CMMS and determine the biosorption mechanisms. The pseudo second order and redox models were able to adequately predict the kinetics of biosorption. The Langmuir maximum OII biosorption capacity (q) was calculated as 136.8 mg/g for the dye onto the Cr(VI)-loaded CMMS consecutive system at C = 100 mg/dm. The q for the Cr(VI) system was found to be 87.32 mg/g at the same C max. This reveals that the biosorption of OII and Cr(VI) mainly takes place via two different mechanisms i.e. hydrogen bonding and electrostatic attraction for the dye, and biosorption-coupled reduction for Cr(VI).

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“…N1s photoelectron spectra and the deconvoluted N species for all four samples can be seen in Figure 6, where N1 corresponds to pyridinic N, N2 to graphitic N and N3 to N-oxides, which are assigned to peaks around 398.1 eV, 400.7 eV and 403 eV, respectively. 39 Fractions of the three N species in all four samples can be found in Table 4. Compared to CN and CNS, CNB and CNSB show almost identical distribution of N species, with 58 % of graphitic and 33 or 32 % of pyridinic N, indicating again that the addition of BA yields a different cryogel morphology/ composition.…”

Section: Influence Of Sulphur and Boron Incorporationmentioning

confidence: 99%

Sustainable metal-free carbogels as oxygen reduction electrocatalysts

et al. 2017

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Time-dependent evolution of the nitrogen configurations in N-doped graphene films

Abstract: Large-area time-controlled N-doped graphene films were grown on a Cu foil using an ammonia-assisted atmospheric pressure chemical vapour deposition (APCVD) technique.

Cited by 138 publications

References 54 publications

Electronic Structure of Nitrogen- and Phosphorus-Doped Graphenes Grown by Chemical Vapor Deposition Method

Electronic Structure of Nitrogen- and Phosphorus-Doped Graphenes Grown by Chemical Vapor Deposition Method

Single, simultaneous and consecutive biosorption of Cr(VI) and Orange II onto chemically modified masau stones

Sustainable metal-free carbogels as oxygen reduction electrocatalysts

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