Carbon nanostructure and reactivity of soot particles from non-intrusive methods based on UV-VIS spectroscopy and time-resolved laser-induced incandescence

The objective of this study is to derive morphological and nanostructural properties soot as well the reactivity against low-temperature oxidation by O2 from easily measurable optical properties. First, ex-situ experiments utilizing thermogravimetric analysis (TGA) high-resolution transmission electron microscopy (HRTEM) serve evaluate kinetics with relate particle morphology nanostructure. Second, ultraviolet–visible (UV-VIS) absorption spectra provide wavelength-dependent cross sections refractive-index functions E(m~,λ). From these, band gap energies, EOG, coefficients ξ∗ for single parameter describing wavelength-dependency E(m~,λ) are obtained. Third, time-resolved laser-induced incandescence (TR-LII) ratios E(m~,λi)/E(m~,λj) at three excitation wavelengths primary size distributions acquired. show that graphene layers predominantly determines oxidation. Graphene layer and, therefore, reflected in UV-VIS E(m~,λ), ξ∗, respectively. Similarly, scattering-corrected TR-LII also reflect hence, reactivity. established strong correlations between properties, characteristics make spectroscopy useful fast in-situ diagnostic methods