ARTICLE | doi:10.20944/preprints202107.0298.v1
Subject: Engineering, Automotive Engineering Keywords: Soot; TEM; HRTEM; EELS; soot nanostructure; premixed flames
Online: 13 July 2021 (11:20:59 CEST)
Soot is characterized by a multiscale structural organization and Transmission Electron Microscope (TEM) is the only diagnostic tool giving access to it. However, being a diffraction-based technique, TEM images only aromatic systems and thus, it is particularly useful to combine it with electron energy-loss spectroscopy (EELS), able to provide quantitative information about the relative abundance of sp3 and sp2 hybridized carbon. In this paper a method for the EELS spectrum analysis of carbonaceous materials recently developed for electron-irradiated graphite and glassy carbon composition analysis has been applied for the first time on soot samples, in order to test its performance in soot nanostructure study in combination with TEM and High Resolution TEM (HRTEM). Soot samples here analysed were collected in the soot inception region of premixed flames of different hydrocarbon fuels. EELS, in agreement with TEM and HRTEM, showed a quite disordered and heterogeneous structure for young soot, without any significant distinction between soot formed from methane and ethylene fuels.