HAL Id: hal-03008218
https://hal.archives-ouvertes.fr/hal-03008218
Submitted on 16 Nov 2020
HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.
L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Coupling of ToF-SIMS and AFM for the identification of the chemical species involved in the nucleation process
of soot particles in flame combustion
Jessy Elias, Xavier Mercier, Alessandro Faccinetto, Nicolas Nuns, Sylvie Godey, Dominique Deresmes, Thierry Melin
To cite this version:
Jessy Elias, Xavier Mercier, Alessandro Faccinetto, Nicolas Nuns, Sylvie Godey, et al.. Coupling of
ToF-SIMS and AFM for the identification of the chemical species involved in the nucleation process
of soot particles in flame combustion. European Aerosol Conference – EAC 2020, Aug 2020, Aachen,
Germany. pp.457. �hal-03008218�
Coupling of ToF-SIMS and AFM for the identification of the chemical species involved in the nucleation process of soot particles in flame combustion
J. Elias 1 , A. Faccinetto 1 , X. Mercier 1 , N. Nuns 2 , S. Godey 3 , D. Deresmes 3 and T. Mélin 3
1 Univ. Lille, CNRS, UMR 8522 - PC2A - Physicochimie des Processus de Combustion et de l’Atmosphère, F-59000 Lille, France
2 Univ. Lille, CNRS, M. E. Chevreul Institut, F-59000 Lille, France
3 Univ. Lille, CNRS, UMR 8520 - IEMN - Institut d'Électronique de Microélectronique et de Nanotechnologie, F-59000 Lille, France
Introduction
Sampling
ToF-SIMS AFM
Perspectives
The soot nucleation process,
corresponding to the transformation of gaseous molecular precursors into condensed phase soot particles, is the less understood step of the soot formation process in flame combustion. The hypothesis of a nucleation process driven by the dimerization of small polycyclic aromatic hydrocarbons (PAHs), has been used in models but experimental evidences are still lacking.
In this work, ToF-SIMS and AFM are coupled with the aim of characterizing the species involved in the soot nucleation process.
Reaction axis
• Laminar methane diffusion flame stabilized at
atmospheric pressure.
• Samples extracted from the centreline of the flame at different heights above the burner (HAB) using a quartz microprobe and deposited on titanium wafers.
Time-of-Flight Secondary Ion Mass Spectrometry
Results
Sample
Mass defect plot Δ = m/z – m Assignement of a molecular formula to the selected m/z.
Principal Component Analysis:
PCA is used to classify the data and explain the variance of the database.
Atomic Force Microscopy delivers direct molecular imaging of the surface at the atomic scale and gives access to the electronic properties of the molecular species.
Preliminary results
Soft spherical structures on a 55 mm HAB sample having a 2-4 nm diameter and a 0.3 Å height, consistent with the size of nascent soot nanoparticles.
In future work, we will use a functionalized CO tip, which probes the molecules with a sub-Å oscillation amplitude at low temperature, to resolve isomeric structures that are detected at the same m/z, for a complete characterization of the species involved in the soot nucleation process.
-0.05 0.00 0.05 0.10
-0.06 -0.04 -0.02 0.00 0.02 0.04 0.06 0.08
131313 151515
2020 20 25 25
25
3030303535 35
404040 454545
50 50
50
51 51 51
52 52 52 535353 54 5454
55 5555 56 56 56 57 5757 585858
6060 60
6565 65 70
70 70
80 80
80
100 100 100
90 9090 57
5757
55 55 13 55
1313 1515 1520
2020 2525 25303030353535
40 4040 4545 45
5050 50 5151
51
52 5252 53
5353 54 54 54 55 5555 565656
57 5757 585858 606060 6565 65 7070 70
80 8080 100100 100
90 90
90
575757 5555 55
Condensable gas phase Soot and condensable gas phase
PC2 (1 7.5 7%)
PC1 (56.68%)
• Different behavior in the nucleation zone of the flame.
• PC1<0 : high mass PAHs
• PC1>0 : low mass PAHs
0 200 400 600 800
0 1000 2000 3000 4000 5000
Ion counts
m/z
Mass spectra at 55 mm HAB
200 300 400 500 600 700
-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5
PC1
m/z
