A molecular-level analysis of gas-phase reactions in chemical vapor deposition of carbon from methane using a detailed kinetic model

Hu, Chunxia; Li, Hejun; Zhang, Shouyang; Li, Wei

doi:10.1007/s10853-015-9709-2

Cited by 18 publications

(7 citation statements)

References 31 publications

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“…The primary goal of this section is to obtain the main reaction pathways of the decomposition of methane during CVI by distinguishing the pathways collected from the previous researches 11,12,29–40 . By studying and summarizing the related researches published previously, detailed reaction schemes for benzene to be prepared using methane as precursor are summarized, as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Conversion of methane to benzene in CVI by density functional theory study

Yan

et al. 2019

Sci Rep

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A density functional theory (DFT) study was employed to explore the mechanism of the conversion of methane to benzene in chemical vapor infiltration (CVI) based on the concluded reaction pathways from C1-species to C6-species. The geometry optimization and vibrational frequency analysis of all the chemical species and transition states (TS) were performed with B3LYP along with a basis set of 6–311 +G(d, p), and Gaussian 09 software was used to perform the study. The rate constants were calculated by KiSThelP according to the conventional transition state theory (TST), and the Wigner method was applied to acquire the tunneling correction factors. Then the rate constants were fitted to the modified Arrhenius expression in the temperature range of 800–2000 K. As for the barrierless reactions calculated in this paper, the rate constants were selected from the relating references. Through the energetic and kinetic calculations, the most favorable reaction pathway for benzene formation from methane was determined, which were mainly made of the unimolecular dissociation. The conversion trend from C1-species to C4-species is mainly guided by a strong tendency to dehydrogenation and the pathways from C4-species to C6-species are all presumed to be able to produce C6H6 molecule.

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Section: Resultsmentioning

confidence: 99%

Conversion of methane to benzene in CVI by density functional theory study

Yan

et al. 2019

Sci Rep

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“…Several reports exist on the gas-phase decomposition or pyrolysis of methane for the deposition of carbon [25,26]. These reports highlight the complex nature of the decomposition.…”

Section: Mechanism Of Graphene Growth Via Cvdmentioning

confidence: 99%

A critical review on the contributions of chemical and physical factors toward the nucleation and growth of large-area graphene

et al. 2018

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Since the first isolation of graphene over a decade ago, research into graphene has exponentially increased due to its excellent electrical, optical, mechanical and chemical properties. Graphene has been shown to enhance the performance of various electronic devices. In addition, graphene can be simply produced through chemical vapor deposition (CVD). Although the synthesis of graphene has been widely researched, especially for CVD growth method, the lack of understanding on various synthetic parameters still limits the fabrication of large-area and defect-free graphene films. This report critically reviews various parameters affecting the quality of CVD-grown graphene to understand the relationship between these parameters and the choice of metal substrates and to provide a point of reference for future studies of large-area, CVD-grown graphene.

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“…Methane pyrolysis produces various hydrocarbons and radicals, ranging from light species, such as hydrogen or methyl, to polyaromatic species, such as pyrene (C 16 H 10 ). In order to reproduce their experimental concentrations, a detailed mechanism with gas elementary reactions had been developed by Hu et al [24]. The mechanism is composed of 909 reversible elementary reactions and 241 radicals and molecules.…”

Section: Homogeneous Reactionsmentioning

confidence: 99%

“…Pressure effects on pressuredependent reactions involving small species are described by Troё parameters [31]. The mechanism has been verified to be able to simulate the species concentrations when pyrocarbon deposition can be ignored [24].…”

Section: Homogeneous Reactionsmentioning

confidence: 99%

Chemical vapor infiltration of pyrocarbon from methane pyrolysis: kinetic modeling with texture formation

Zhang

et al. 2018

Sci. China Mater.

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A complete mechanism of methane pyrolysis is proposed for chemical vapor infiltration of pyrocarbon with different textures, which contains a detailed homogeneous mechanism for gas reactions and a lumped heterogeneous mechanism for pyrocarbon deposition. This model is easily applied to simulate gas compositions and pyrocarbon deposition in a vertical hot-wall flow reactor in the temperature range of 1,323-1,398 K without any adjusting parameters and presents better results than previous mechanisms. Results have shown that the consumption of methane and the production of hydrogen are well enhanced due to pyrocarbon deposition. Pyrocarbon deposition prevents the continuously increasing of acetylene composition and leads to the reduction in the mole fraction of benzene at long residence times in the gas phase. The carbon growth with active sites on the surface is the controlling mechanism of pyrocarbon deposition. C 1 species is the precursor of pyrocarbon deposition at 1,323 K, and the primary source over the whole temperature range. As temperature increases, gas phase becomes more mature and depositions from acetylene, benzene and polyaromatic hydrocarbons become more prevalent. A general pyrocarbon formation mechanism is derived with the specific precursors and illustrates that the maturation of gas compositions is beneficial to forming planar structures with hexagonal rings or pentagon-heptagon pairs, namely, high textured pyrocarbon. The results are in well agreement with experiments.

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A molecular-level analysis of gas-phase reactions in chemical vapor deposition of carbon from methane using a detailed kinetic model

Cited by 18 publications

References 31 publications

Conversion of methane to benzene in CVI by density functional theory study

Conversion of methane to benzene in CVI by density functional theory study

A critical review on the contributions of chemical and physical factors toward the nucleation and growth of large-area graphene

Chemical vapor infiltration of pyrocarbon from methane pyrolysis: kinetic modeling with texture formation

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