Reducing and multiple-element doping of graphene oxide using active screen plasma treatments

Chen, Jian; Shi, Xiaoyan; Qi, Shaojun; Mohai, M.; Bertóti, I.; Gao, Ying; Dong, Hanshan

doi:10.1016/j.carbon.2015.08.046

Cited by 25 publications

(19 citation statements)

References 53 publications

(60 reference statements)

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“…This feature can be assigned to multiple bonds of carbon with nitrogen and with the different bonds with oxygen. Another similar study using XPS to analyze the composition and chemical state of GO treated by H 2 plasma and a gas mixture of H 2 and N 2 was done by Chen et al Various identified carbon‐oxygen bonds, CO in COH, epoxy type COC, carbonyl type CO, and carboxylic type O(CO), are similar to our results. The work also suggests CO is unstable which can be reduced by effective plasma treatment.…”

Section: Resultssupporting

confidence: 90%

The chemistry and topography of stabilized and functionalized graphene oxide coatings

Awaja

Wong

O’Brien

et al. 2018

Plasma Processes & Polymers

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Graphene oxide (GO) thin films and coatings are regarded as superior in quality to other materials especially for biomedical applications. However, the lack of stability and understanding of their structure and defects hinder their use in value added applications. Here, we describe our successful attempt at stabilizing, reducing and functionalizing GO through multiple plasma treatments with polymerizing (to deposit a crosslinking and compressing layer of diamond like carbon, DLC) and non‐polymerizing precursors (H2, O2, and N2). The hybrid GO and DLC coatings on semi crystalline PEEK were evaluated using AFM, SEM, and XPS. The GO deposited layer showed roughness around 70 nm and, despite care, resulted in several wrinkles and particle aggregations. The hybrid coatings conformed to the roughness and crystalline features of PEEK. XPS showed that the DLC layer cross‐linked the GO nano‐flakes while not completely masking which enable the partial exposure of GO. The GO‐DLC hybrid interface is higher in thickness than the PEEK‐GO and is dominating the overall thickness of the hybrid structure ≈13 ± 1 μm. XPS measurements showed that the often unstable CO functional groups on the surface of the hybrid coating can be reduced by effective plasma treatment. Plasma treatments also generated CO functional groups that probably originated from the decomposed carboxyl groups. The plasma treatment also contributed to the reduction of GO. Treatment with H2 was more effective in oxygen reduction than with the N2, however, treatment with N2 increased the reactants on GO as N2 is heavier tending to deposit more on a surface. Plasma treatment with O2 increased the surface oxygen content further and hence more defects on the hybrid surface.

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Section: Resultssupporting

confidence: 90%

The chemistry and topography of stabilized and functionalized graphene oxide coatings

Awaja

Wong

O’Brien

et al. 2018

Plasma Processes & Polymers

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“…Four different O functional groups as well as a contribution of adsorption oxygen are identified. The peak at 529.7 eV corresponds to oxygen ions (O a ) bonded to Fe cations in a coordinatively saturated environment (Fe═O); the peak at 530.4 eV corresponds to oxygen atoms in keto and quinone groups (C═O); the peak at 531.5 eV corresponds to the K―O bonds; the peak at 532.2 eV corresponds to the oxygen atoms bond to carbon atoms in form of single bond (C―OH or C―O―C); and the peak at 533.1 eV corresponds to the single bonded oxygen in carboxylic group (O―C═O) …”

Section: Resultsmentioning

confidence: 99%

Fe/MCSAC catalysts surface modified with nitrogen DBD non‐thermal plasma for carbonyl sulfide catalytic hydrolysis activity enhancement

Liu

Ning

et al. 2017

Surface & Interface Analysis

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The removal of carbonyl sulfide (COS or S=C=O) from gas streams over Fe/microwave coconut-shell activated carbon (MCSAC) catalysts modified by dielectric barrier discharge non-thermal plasma (NTP) were investigated. The properties of Fe/MCSAC catalysts modified by NTP in different conditions, included kinds of reactors, treatment times and input voltages. The surface properties were evaluated by means of energy-dispersive X-ray spectrometry, Brunauer Emmett Teller, X-ray photoelectron spectroscopy methods and theoretical calculation, which could help us understand the effects of the plasma treatment. The experiments results showed that the COS hydrolysis activities of Fe/MCSAC catalysts were largely enhanced after NTP modification. And the optimal reactor type, treatment time and input voltage were plate-plate type, 10 min and 35 V, respectively. The catalytic activity enhanced effectually due to the improvement of active component's dispersion after NTP modification. In addition, the extended oxygen functional groups on NTP-modified catalyst's surface could contribute to a higher activity for COS catalytic hydrolysis at low temperature. The investigation results indicate that non-thermal plasma treatment is an effective way to manipulate catalyst surface properties for COS catalytic hydrolysis reaction.

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“…The GO coatings can be produced by chemical methods [23], dissolving graphene powder and other salts in sulfuric acid, subsequently dispersing and exfoliating the GO nanosheets by sonication, and finally casting it onto the substrate. A reduction process is then required to remove the oxygen functionalities and obtain a graphene coating of high quality, and the ASP technology was used for this purpose [24]. The ASP treatments were conducted at 400 Pa in pure H 2 or N 2 -H 2 mixtures, at temperatures between 100 and 200°C for 1 h. The appearance of coatings changed from a light brown color to silver-gray after the plasma reduction in pure hydrogen and nitrogen-hydrogen mixtures, and this change was accompanied by a decrease in optical transparency and electrical resistance of the coating (Figure 2.3).…”

Section: Reduction Of Graphene Oxide For Optoelectronic Devicesmentioning

confidence: 99%

2 Plasma surface activation and functionalization of carbon-based materials

Dong¹,

Gallo²

2020

Carbon-Based Smart Materials

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Reducing and multiple-element doping of graphene oxide using active screen plasma treatments

Cited by 25 publications

References 53 publications

The chemistry and topography of stabilized and functionalized graphene oxide coatings

The chemistry and topography of stabilized and functionalized graphene oxide coatings

Fe/MCSAC catalysts surface modified with nitrogen DBD non‐thermal plasma for carbonyl sulfide catalytic hydrolysis activity enhancement

2 Plasma surface activation and functionalization of carbon-based materials

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