Enhanced Magnetism by Temperature Induced Defects in Reduced Graphene Oxide Prepared From Coconut Shells

Darminto, Darminto; Asih, Retno; Kurniasari,; Baqiya, Malik Anjelh; Mustofa, Salim; Suasmoro,; Kawamata, Takayuki; Kato, Takayuki; Watanabe, Isao; Koike, Yasuhiro

doi:10.1109/tmag.2018.2864946

Cited by 22 publications

(28 citation statements)

References 31 publications

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“…Meanwhile, natural carbon sources are also available in the form of biomaterials derived from plants, either as products (bio-products) or waste (bio-waste), which are more environmentally friendly. An rGO-like structure has been found standing on natural carbon sources, coconut shell charcoal, by the facile synthesis, including the heating and the exfoliation processes [15,16,17,18]. Differences in synthesis route and treatment provide a unique and different nature of the obtained rGO [2].…”

Section: Introductionmentioning

confidence: 99%

Mesostructural study on graphenic-based carbon prepared from coconut shells by heat treatment and liquid exfoliation

Ristiani

Asih

Astuti

et al. 2022

Heliyon

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Section: Introductionmentioning

confidence: 99%

Mesostructural study on graphenic-based carbon prepared from coconut shells by heat treatment and liquid exfoliation

Ristiani

Asih

Astuti

et al. 2022

Heliyon

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“…Analyses on phase and functional groups presented in the samples have been reported in [22,23]. Two broad peaks at 2θ of about 24 • and 43 • were observed in XRD patterns of the samples, indicating the presence of the rGO-like phase.…”

Section: Resultsmentioning

confidence: 88%

“…Our previous studies reported that magnetization of the rGO-like phase synthesized from coconut shell strongly depends on defects [22,23]. The magnetization enhances when the concentration of defect increases, and this can be tuned by controlling temperature applied in the thermal reduction process [22]. The saturation magnetization of rGO-s is larger than that in rGO-c as rGO-s has more defects compared with rGO-c [23].…”

Section: Resultsmentioning

confidence: 99%

“…The physical features of the samples influence their electrical and magnetic properties. Our previous studies reported that magnetization of the rGO-like phase synthesized from coconut shell strongly depends on defects [22,23]. The magnetization enhances when the concentration of defect increases, and this can be tuned by controlling temperature applied in the thermal reduction process [22].…”

Section: Resultsmentioning

confidence: 99%

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Physical Properties Comparison of rGO-like phase prepared from Coconut Shell and the Commercial Product

Asih

Septya

Yutomo

et al. 2020

JFA

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Electrical dan magnetic properties of graphene-derivatives materials are strongly influenced by their physical properties. Here we report a study on physical properties of reduced graphene oxide (rGO) prepared from two different raw materials, namely coconut shell (rGO-s) and graphite mineral (rGO-c, produced by Graphenea Inc.). rGO-s was prepared by carbonization method followed by mechanical exfoliation. While both samples have the same density of about 1.9 g/cm 3 , rGO-c has more porous compared to rGO-s. Specific surface area in rGO-c was also obtained much larger than that of rGO-s. Examinations on particle size and surface morphology show that rGO-c has homogenous particles which consist of transparent thin sheets, while rGO-s has rather heterogenous particles that look like dens stacked sheets. The presence of C and O was confirmed at the observed morphology. The difference in physical features was found to influence the obtained electrical conductivity of the samples. rGO-c has higher conductivity than rGO-s. Estimation on gap energy (Eg) indicates that rGO-c and rGO-s have Eg in the range of semiconducting materials. The study provides a better understanding on physical properties of coconut shell-derived rGO to further revise synthesis method to improve quality of the obtained rGO.

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“…The presence of these "impurity" bonds can be considered a source of electric dipoles. Furthermore, the formation of a magnetic moment is also possible, owing to heating at 400 ℃ to create a number of dangling bonds with unpaired electrons [26]. The electric dipole, along with the magnetic moment, is responsive to electromagnetic waves to induce absorption or RL [18,19,26].…”

Section: Structural Analysesmentioning

confidence: 99%

Preparation and Thickness Optimization of Graphenic-Based Carbon Material as a Microwave Absorber

et al. 2022

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The purpose of this study is to optimize the thickness of a layered graphenic-based carbon compound, which is a non-magnetic material derived from biomass (old coconut shell). After the sample was exfoliated using HCl solution, the morphological structure showed that the material used in this study is a reduced graphene oxide (rGO), similar to carbon but with a thickness of less than 10 nm and lateral size in submicron (100 nm). The sample with a 2 mm thickness was then characterized using a vector network analyzer (VNA) to measure its reflection loss (RL). The measurement result is evaluated by converting the S-parameter values (S11 and S21) from the VNA using the Nicolsson Ross Weir (NRW) method to obtain input variables such as relative complex permeability and relative complex permittivity. Following this, the single-layer thickness of the sample was optimized using a genetic algorithm (GA), which can predict the appropriate thickness so that the optimum RL can be obtained. The optimum thickness of the sample was found to be 3.48 mm, which resulted in a much higher RL. The RL was re-measured for verification using a sample with the corresponding optimized thickness, revealing that this optimization is feasibly operational for a radar absorbing material (RAM) design. HIGHLIGHTS Carbon compounds containing graphenic phase derived from coconut shell are functional materials having various unique properties such as superior electrical conductivity, large surface area, and excellent structural flexibility, and microwave absorbtion The single-layer microwave absorber employing carbon compounds has been prepared The layer thickness optimized using a genetic algorithm (GA) can estimate the appropriate design with the maximum reflection loss (RL)

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Enhanced Magnetism by Temperature Induced Defects in Reduced Graphene Oxide Prepared From Coconut Shells

Cited by 22 publications

References 31 publications

Mesostructural study on graphenic-based carbon prepared from coconut shells by heat treatment and liquid exfoliation

Mesostructural study on graphenic-based carbon prepared from coconut shells by heat treatment and liquid exfoliation

Physical Properties Comparison of rGO-like phase prepared from Coconut Shell and the Commercial Product

Preparation and Thickness Optimization of Graphenic-Based Carbon Material as a Microwave Absorber

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