Zeolite-Assisted Shear Exfoliation of Graphite into Few-Layer Graphene

Usca, Gabriela Tubon; Gomez, Cristian Vacacela; Guevara, Marco; Tene, Talia; Hernández, José Fernando Placeres; Molina, Raúl Cobo; Tavolaro, Adalgisa; Miriello, Domenico; Caputi, Lorenzo

doi:10.3390/cryst9080377

Cited by 17 publications

(8 citation statements)

References 35 publications

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“…The proposed AAE process relies on the judicious choice of an additive. Unlike previous approaches, such as shear grinding exfoliation [21] and zeolite-assisted exfoliation [22], the envisioned additive decreases the rotor-stator gap without modifying the exfoliation process or getting consumed during exfoliation. Therefore, suitable additives must be chemically stable in the exfoliation solution and be mechanically tough enough not to fragment in shear exfoliation but not too hard to cause damage to the mixer's head.…”

Section: Resultsmentioning

confidence: 99%

“…Finally, the ease of removing the additive from the exfoliated material is another factor to consider. After surveying a number of additives, including nickel, diatomaceous earth, zeolite powder [22] and paint-coated silica particles for these requirements (Table S1 in the Supplementary Material), we identified polytetrafluoroethylene (PTFE) spheres of 4 µm diameter as the most promising candidate. PTFE has a low hardness of 4.8 [23], is chemically inert in commonly employed solvents and does not exfoliate.…”

Section: Resultsmentioning

confidence: 99%

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Additive-Enhanced Exfoliation for High-Yield 2D Materials Production

Nguyen

Ting

et al. 2021

Nanomaterials

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The success of van-der-Waals electronics, which combine large-scale-deposition capabilities with high device performance, relies on the efficient production of suitable 2D materials. Shear exfoliation of 2D materials’ flakes from bulk sources can generate 2D materials with low amounts of defects, but the production yield has been limited below industry requirements. Here, we introduce additive-assisted exfoliation (AAE) as an approach to significantly increase the efficiency of shear exfoliation and produce an exfoliation yield of 30%. By introducing micrometer-sized particles that do not exfoliate, the gap between rotor and stator was dynamically reduced to increase the achievable shear rate. This enhancement was applied to WS2 and MoS2 production, which represent two of the most promising 2D transition-metal dichalcogenides. Spectroscopic characterization and cascade centrifugation reveal a consistent and significant increase in 2D material concentrations across all thickness ranges. Thus, the produced WS2 films exhibit high thickness uniformity in the nanometer-scale and can open up new routes for 2D materials production towards future applications.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Additive-Enhanced Exfoliation for High-Yield 2D Materials Production

Nguyen

Ting

et al. 2021

Nanomaterials

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“…Although there are several methods for synthesizing graphene and its derivatives (e.g., liquid exfoliation [ 43 , 44 ], zeolite-assisted exfoliation [ 45 ], hydrothermal exfoliation [ 46 ], and microwave-assisted exfoliation [ 47 , 48 , 49 , 50 , 51 , 52 , 53 ]), the present study focuses on the eco-friendly oxidation-reduction protocol [ 33 ] to transform as-made GO into rGO.…”

Section: Methodsmentioning

confidence: 99%

Cationic Pollutant Removal from Aqueous Solution Using Reduced Graphene Oxide

et al. 2022

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Reduced graphene oxide (rGO) is one of the most well-known graphene derivatives, which, due to its outstanding physical and chemical properties as well as its oxygen content, has been used for wastewater treatment technologies. Particularly, extra functionalized rGO is widely preferred for treating wastewater containing dyes or heavy metals. Nevertheless, the use of non-extra functionalized (pristine) rGO for the removal of cationic pollutants is not explored in detail or is ambiguous. Herein, pristine rGO—prepared by an eco-friendly protocol—is used for the removal of cationic pollutants from water, i.e., methylene blue (MB) and mercury-(II) (Hg-(II)). This work includes the eco-friendly synthesis process and related spectroscopical and morphological characterization. Most importantly, the investigated rGO shows an adsorption capacity of 121.95 mg g−1 for MB and 109.49 mg g−1 for Hg (II) at 298 K. A record adsorption time of 30 min was found for MB and 20 min for Hg (II) with an efficiency of about 89% and 73%, respectively. The capture of tested cationic pollutants on rGO exhibits a mixed physisorption–chemisorption process. The present work, therefore, presents new findings for cationic pollutant adsorbent materials based on oxidized graphenes, providing a new perspective for removing MB molecules and Hg(II) ions.

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“…A few layers of graphene were synthesized by evaporating polystyrene at atmospheric pressure by the chemical vapor deposition (APCVD) method 9 , 10 . Graphene sheets can be extracted through sonication 11 or shear exfoliation 12 in an aqueous surfactant solution and certain organic solvents. Several groups have shown that graphene can be prepared in N -methyl-2-pyrrolidone 13 (NMP), and dimethylformamide 14 (DMF), to produce graphene nano-sheets.…”

Section: Introductionmentioning

confidence: 99%

Verification of experimental results with simulation on production of few-layer graphene by liquid-phase exfoliation utilizing sonication

Mushfiq

Afzalzadeh

2022

Sci Rep

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Graphene, an extraordinary tow-dimensional carbon nanostructure, has attracted global attention due to its electronic, mechanical, and chemical properties; therefore, there is a need to find out an economical mass production method to produce graphene. In the present research, the aim is to find out optimal conditions for exfoliation of few-layers graphene (FLG) in a water–ethanol green solution. We varied different parameters of the ultrasonic probe like power quantity and time duration of sonication to investigate the effects on the number of graphene layers and density of graphene in the solution. Also, an attempt has been made to predict the acoustic pressure distribution by solving the wave equation in various output powers of the ultrasonic probe (sonotrode) using numerical simulations. The simulations and experimentations verify each other. Concluding that modifying the output power at the same condition will significantly alter the acoustic pressure inside the sonoreactor. The difference in acoustic pressure at 90% output power of our experimentations is much higher than in other conditions. Experimentation results utilizing UV–visible spectra, SEM (Scanning electron microscope), TEM (Transmission electron microscope) images and Raman spectrum indicate that the minimum thickness and maximum exfoliation for these samples are acquired for sonication at 90% of the maximum effective output power of the sonicator being 264 W for 55 min.

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Zeolite-Assisted Shear Exfoliation of Graphite into Few-Layer Graphene

Cited by 17 publications

References 35 publications

Additive-Enhanced Exfoliation for High-Yield 2D Materials Production

Additive-Enhanced Exfoliation for High-Yield 2D Materials Production

Cationic Pollutant Removal from Aqueous Solution Using Reduced Graphene Oxide

Verification of experimental results with simulation on production of few-layer graphene by liquid-phase exfoliation utilizing sonication

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