M17 - Graphenic Quantum Dots in Natural Carbonaceous Materials

Monday, October 6, 2025

9:45 AM - 5:30 PM EDT

Location: Ballroom C

Presenting Author(s)

Dale L. Perry

Senior Scientist (Chemistry)
Lawrence Berkeley National Laboratory, University of California
Hercules, California, United States

Project Lead(s)

NK

Nataliya Kalashnyk

University Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, UMR 8520 -IEMN – Institut d’Electronique, de Microélectronique et de Nanotechnologie, F-59000 Lille, France
Lille, Alsace, France

Non-Presenting Author(s)

YL

Yves Lulzac

Centre de Recherche Gemmologique, 2 rue de la Houssinière, F-44322 Nantes cedex 3, France
Nantes, Alsace, France
YM

Yves Moëlo

Nantes Université, CNRS, Institut des Matériaux de Nantes Jean Rouxel, IMN, F-44000 Nantes, France
Nantes, Alsace, France
EF

Eric Faulques

University Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, UMR 8520 -IEMN – Institut d’Electronique, de Microélectronique et de Nanotechnologie, F-59000 Lille, France
Lille, Alsace, France

Submitter(s)

Dale L. Perry

Senior Scientist (Chemistry)
Lawrence Berkeley National Laboratory, University of California
Hercules, California, United States

In fifteen words or less, explain the significance of this contribution (Novel Aspect).: Nanostructures of natural materials have been studied using uniquely, complementary instrumental techniques.

Abstract Text:

We investigate the nanostructure of two natural carbonaceous materials, a Karelian shungite (KS), and a rare pyrobitumen (proto-shungite, PY) from Brittany, France, using X-ray diffraction (XRD), multi-wavelength Raman spectroscopy, and scanning electron microscopy [1]. The inter-reticular distances d(002) for PY/KS, derived from XRD patterns, are 3.57(1)/3.48(1) Å, with crystal thickness Lc(002) and graphitization degree of 1.4/2.0 nm and 6.9/13.1, respectively. The Raman spectra of both materials display sharp D, G, and 2D bands, characteristic of graphenic structures. A detailed analysis of the band profiles and positions reveals that the samples partly consist of assemblies of graphitic nanodomains, which can be regarded as graphene quantum dots, as proposed by Razbirin et al. [2] and supported by high-resolution transmission electron microscopy observations [3,4]. Density functional theory simulations on graphene quantum dot models accurately reproduce the experimental D and G band profiles. The pyrobitumen sample, characterized by a lower density (1.60 g/cm³) and greater structural disorder, exhibits a reduced degree of graphitization, consistent with its hydrothermal origin at ~300 °C through redox interactions between CO₂-rich fluids and a hydrocarbon source. These results highlight the structural diversity and quantum-scale organization of natural graphenic domains in these carbonaceous materials.

[1] E.Faulques et al. Carbon Trends 17 (2024) 100421,https://doi.org/10.1016/j.cartre.2024.100421

[2] B.S. Razbirin et al. J. Exp. Theor. Phys. 118 (2014) 735–746

https://doi.org/10.1134/S1063776114050161

[3] P.R. Buseck, O. Beyssac Elements 10 (2014) 421, https://doi.org/10.2113/gselements.10.6.421

[4] Y. Golubev et al., Eur. J. Mineral. 28 (2016) 545, https://doi.org/10.1127/ejm/2016/0028-2537