Chemical Kinetics of Soot Particle Growth

Harris, Stephen J.; Weiner, Anita M.

doi:10.1146/annurev.pc.36.100185.000335

Cited by 151 publications

(80 citation statements)

References 19 publications

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“…Harris and Weiner reviewed the progresses made in this field. [229] Tesner et al calculated that the rate of carbon deposition for methane obeys the following rate law for temperatures above 900 K: [229] ð1=SÞdM=dt ¼ 810½CH4expðÀ65 000=RTÞ g cm À2 s…”

Section: Cvd or Ccvd?mentioning

confidence: 99%

Recent Progress on the Growth Mechanism of Carbon Nanotubes: A Review

2011

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Tremendous progress has been achieved during the past 20 years on not only improving the yields of carbon nanotubes and move progressively towards their mass production, but also on gaining a profound fundamental understanding of the nucleation and the growth processes. Parameters that influence the yield but also the quality (e.g., microstructure, homogeneity within a batch) are better understood. The influence of the carbon precursor, the reaction conditions, the presence of a catalyst, the chemical and physical status of the latter, and other factors have been extensively studied. The purpose of the present Review is not to list all the experiments reported in the literature, but rather to identify trends and provide a comprehensive summary on the role of selected parameters. The role of the catalyst occupies a central place in this Review as a careful control of the metal particle size, particle dispersion on the support, the metastable phase formed under reaction conditions, its possible reconstruction, and faceting strongly influence the diameter of the carbon nanotubes, their structure (number of walls, graphene sheet orientation, chirality), their alignment, and the yield. The identified trends will be compared with recent observations on the growth of graphene. Recent results on metal-free catalysts will be analyzed from a different perspective.

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Section: Cvd or Ccvd?mentioning

confidence: 99%

Recent Progress on the Growth Mechanism of Carbon Nanotubes: A Review

2011

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“…Another correlation which may be of significance is 'he rapid increase in [C 2 H 2 ] with pres-sure, as seen in Figure 6. Although acetylene can be a precursor for diamond [35,36], it can also be a precursor for sp 2 carbon [37].…”

Section: Effects Of Pressure On Diamond Qualitymentioning

confidence: 99%

Pressure and temperature effects on the kinetics and quality of diamond films

Harris

Weiner

1994

Journal of Applied Physics

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Quantitative measurements of the effects of pressure on the kinetics and quality of diamond films grown with hot-filament chemical-vapor deposition are reported. Pressure affects growth kinetics largely because it affects transport of precursors to the growing surface. H and CH3 concentrations at the growth surfaces are determined with a recombination enthalpy technique combined with appropriate transport analyses. The growth rate rises and then falls with increasing pressure, although the concentrations of CH3 and atomic hydrogen at the surface are nearly constant. Both the rise and the fall in growth rate at higher pressure are explained with a chemical kinetics model as due in large part to an increase in substrate temperature at higher pressures. The fall at higher pressure (temperature) is due to the rate of thermal desorption of the CH3 precursor increasing more rapidly with temperature than the competing rate of its incorporation: Once these rates become comparable, higher substrate temperatures lower the incorporation rates, and the growth rate decreases. Previously measured Arrhenius plots for diamond-growth kinetics are explained quantitatively. The quality of the diamond, as determined using Raman and scanning electron micrograph data, falls with increasing pressure and substrate temperature. For the first time, this decline in quality is correlated with experimental temperature, H:CH3 ratio, and C2H2 concentration measurements.

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“…Soot is the product of incomplete combustion of hydrocarbon fuels and consists mainly of carbon (, 90%). Carbon surfaces are known to be catalytic for the conversion of SO 2 to SO 4 22 , and NO to NO 2 or NO 3 2 in the atmosphere [1]. Soot is one of the first recognized environmental carcinogens.…”

Section: Introductionmentioning

confidence: 99%

Experimental and artificial neural network modeling study on soot formation in premixed hydrocarbon flames☆

İnal

Tayfur

Melton

et al. 2003

Fuel

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The formation of soot in premixed flames of methane, ethane, propane, and butane was studied at three different equivalence ratios. Soot particle sizes, number densities, and volume fractions were determined using classical light scattering measurement techniques. The experimental data revealed that the soot properties were sensitive to the fuel type and combustion parameter equivalence ratio. Increase in equivalence ratio increased the amount of soot formed for each fuel. In addition, methane flames showed larger particle diameters at higher distances above the burner surface and propane, ethane, and butane flames came after the methane flames, respectively. Three-layer, feedforward type artificial neural networks having seven input neurons, one output neuron, and five hidden neurons for soot particle diameter predictions and seven hidden neurons for volume fraction predictions were used to model the soot properties. The network could not be trained and tested with sufficient accuracy to predict the number density due to a large data range and greater uncertainty in determination of this parameter. The number of complete data set used in the model was 156. There was a good agreement between the experimental and predicted values, and neural networks performed better when predicting output parameters (i.e. soot particle diameters and volume fractions) within the limits of the training data. q

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Chemical Kinetics of Soot Particle Growth

Cited by 151 publications

References 19 publications

Recent Progress on the Growth Mechanism of Carbon Nanotubes: A Review

Recent Progress on the Growth Mechanism of Carbon Nanotubes: A Review

Pressure and temperature effects on the kinetics and quality of diamond films

Experimental and artificial neural network modeling study on soot formation in premixed hydrocarbon flames☆

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