Aaron J. Tomasek

Soot oxidation: dependence upon initial nanostructure

Although the relation between carbon structure and reactivity is well-known from thermal and oxidative studies of coal, char, and graphite, the relation for soot remains unstudied. In this article, the dependence of the soot oxidation rate upon the length and curvature of the graphene segments, which depicts the nanostructure, is shown. Reflecting different ratios of edge to basal plane sites or amounts of ring strain imposed by curvature, burnout rates are found to differ by greater than 400% for the soots studied here. Surprisingly, the different soot nanostructures are readily produced by using different fuels and pyrolysis conditions.

Carbon Nanostructure Examined by Lattice Fringe Analysis of High Resolution Transmission Electron Microscopy Images

The dimensions of graphitic layer planes directly affect the reactivity of soot towards oxidation and growth. Quantification of graphitic structure could be used to develop and test correlations between the soot nanostructure and its reactivity. Based upon transmission electron microscopy images, this paper provides a demonstration of the robustness of a fringe image analysis code for determining the level of graphitic structure within nanoscale carbon, i.e., soot. Results, in the form of histograms of graphitic layer plane lengths, are compared to their determination through Raman analysis.