Full graphitization of amorphous carbon by microwave heating

Kim, Teawon; Lee, Jaegeun; Lee, Kun‐Hong

doi:10.1039/c6ra01989g

Cited by 87 publications

(39 citation statements)

References 55 publications

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“…For the graphitic carbon material, two strong resonance peaks at 1580 and 1350 cm −1 were observed. A peak at 1580 cm −1 represents the vibration in an ideal graphite lattice (G) band [30,52,60]. Meanwhile, the D (1350 cm −1 ) band appeared with the increase in structural defects due to imperfections or loss of hexagonal symmetry [45,61].…”

Section: Crystallographic Propertiesmentioning

confidence: 99%

A Modification of Palm Waste Lignocellulosic Materials into Biographite Using Iron and Nickel Catalyst

2021

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This paper presents an alternative way to maximize the utilization of palm waste by implementing a green approach to modify lignocellulosic materials into a highly crystalline biographite. A bio-graphite structure was successfully synthesized by converting lignocellulosic materials via a simple method using palm kernel shell (PKS) as a carbon precursor. This involved the direct impregnation of a catalyst into raw material followed by a thermal treatment. The structural transformation of the carbon was observed to be significantly altered by employing different types of catalysts and varying thermal treatment temperatures. Both XRD and Raman spectroscopy confirmed that the microstructural alteration occurred in the carbon structure of the sample prepared at 800 and 1000 °C using iron, nickel or the hybrid of iron-nickel catalysts. The XRD pattern revealed a high degree of graphitization for the sample prepared at 1000 °C, and it was evident that iron was the most active graphitization catalyst. The presence of an intensified peak was observed at 2θ = 26.5°, reflecting the formation of a highly ordered graphitic structure as a result of the interaction between the iron catalyst and the thermal treatment process at 1000 °C. The XRD observation was further supported by the Raman spectrum in which PKS-Fe1000 showed a lower defect structure associated with the presence of a significant amount of graphitic structure, as a low value of (Id/Ig) ratio was reported. An HRTEM image showed a well-defined lattice fringe seen on the structure for PKS-Fe1000; meanwhile, a disordered microstructure was observed for the control sample, indicating that successful structural modification was achieved with the aid of the catalyst. Further analysis from BET found that the PKS-Fe1000 developed a surface area of 202.932 m2/g with a pore volume of 0.208 cm3/g. An overall successful modification from palm waste into graphitic material was achieved. Thus, this study will help those involved in waste management to evaluate the possibility of a sustainable process for the generation of graphite material from palm waste. It can be concluded that palm waste is a potential source of production for graphite material through the adoption of the proposed waste management process.

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Section: Crystallographic Propertiesmentioning

confidence: 99%

A Modification of Palm Waste Lignocellulosic Materials into Biographite Using Iron and Nickel Catalyst

2021

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“…Typically, the d-spacing is correlated with the graphitization degree, which also depends on the graphitization time. Given the same processing time, catalytic microwave graphitization can lower the d-spacing value (0.336 nm) more effectively than thermal graphitization [ 54 ].…”

Section: Resultsmentioning

confidence: 99%

Structure of Coal-Derived Metal-Supported Few-Layer Graphene Composite Materials Synthesized Using a Microwave-Assisted Catalytic Graphitization Process

et al. 2021

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Metal-supported few-layer graphene (FLG) was synthesized via microwave-assisted catalytic graphitization owing to the increasing demand for it and its wide applications. In this study, we quickly converted earth-abundant and low-cost bituminous coal to FLG over Fe catalysts at a temperature of 1300 °C. X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and N2 adsorption–desorption experiments were performed to analyze the fabricated metal-supported FLG. The results indicated that the microwave-irradiation temperature at a set holding-time played a critical role in the synthesis of metal-supported FLG. The highest degree of graphitization and a well-developed pore structure were fabricated at 1300 °C using a S10% Fe catalyst for 20 min. High-resolution transmission electron microscopy analysis confirmed that the metal-supported FLG fabricated via microwave-assisted catalytic graphitization consisted of 3–6 layers of graphene nanosheets. In addition, the 2D band at 2700 cm−1 in the Raman spectrum of the fabricated metal-supported FLG samples were observed, which indicated the presence of few-layer graphene structure. Furthermore, a mechanism was proposed for the microwave-assisted catalytic graphitization of bituminous coal. Here, we developed a cost-effective and environmental friendly metal-supported FLG method using a coal-based carbonaceous material.

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“…Perfect graphite, corresponded to the G‐band, is characterized by a single high‐frequency band at 1582 cm −1 . Disordered carbon, corresponded to the D‐band, is characterized by the broad band at approximately 1350 cm −1 . The I D /I G are defined as the ratio of the integrated peak areas of the G‐band to the D‐band, which is used to characterize the graphitization degree of char layer.…”

Section: Resultsmentioning

confidence: 99%

Application of waste silicon rubber composite treated by N₂ plasma in the flame‐retardant polypropylene

Zhang

Jia

et al. 2019

J of Applied Polymer Sci

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The waste silicon rubber composite insulator (WSiRC) was applied along with ammonium polyphosphate (APP) and pentaerythritol (PER) to improve the flame retardancy of polypropylene (PP) in this study. Considering the compatibility among PP, WSiRC, and flame-retardant additives, WSiRC was treated by acid and N 2 plasma to obtain the plasma-treated WSiRC (PLSiR), which decreases the amount of the inorganic additive and grafts amino groups onto the surface of the silicon rubber. The infrared spectrocopy (IR), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA) confirm that NH 2 groups have been grafted onto the surface of PLSiR. The TGA data also show that PLSiR had the char improving ability and promote the crosslink of APP, which results in its promotion for the flame retartancy of PP proved by the data of limiting oxygen index (LOI), UL94 rating and cone tests. It is also showed that PLSiR is superior than the WSiRC treated only by acid (ASiR) due to the differences in the structure and polarity. Moreover, the improvement of PLSiR on the flame retardancy of PP is dependent on its amounts. It is indicated that the 1 wt % loading of PLSiR in PP with APP and PER has the highest LOI value of 30.9 and reached UL94 rating V-0. The peak heat release rate (pHRR) and total heat release (THR) values are also decreased by 68.7 and 15%, respectively. SEM and Raman results show the condensed mechanism is ascribed to the PP/APP-PER/PLSiR system because the quality of char affect the flame retardancy of PP.

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Full graphitization of amorphous carbon by microwave heating

Abstract: Natural graphite is labelled as a supply risk material due to rapidly increasing demand and limited reserves.

Cited by 87 publications

References 55 publications

A Modification of Palm Waste Lignocellulosic Materials into Biographite Using Iron and Nickel Catalyst

A Modification of Palm Waste Lignocellulosic Materials into Biographite Using Iron and Nickel Catalyst

Structure of Coal-Derived Metal-Supported Few-Layer Graphene Composite Materials Synthesized Using a Microwave-Assisted Catalytic Graphitization Process

Application of waste silicon rubber composite treated by N₂ plasma in the flame‐retardant polypropylene

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Full graphitization of amorphous carbon by microwave heating

Abstract: Natural graphite is labelled as a supply risk material due to rapidly increasing demand and limited reserves.

Cited by 87 publications

References 55 publications

A Modification of Palm Waste Lignocellulosic Materials into Biographite Using Iron and Nickel Catalyst

A Modification of Palm Waste Lignocellulosic Materials into Biographite Using Iron and Nickel Catalyst

Structure of Coal-Derived Metal-Supported Few-Layer Graphene Composite Materials Synthesized Using a Microwave-Assisted Catalytic Graphitization Process

Application of waste silicon rubber composite treated by N2 plasma in the flame‐retardant polypropylene

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Application of waste silicon rubber composite treated by N₂ plasma in the flame‐retardant polypropylene