Missions

The aim of this postDoc is to characterize and understand the phenomenon of crystal growth of carbon layers on nanoparticles, under conditions representative of a laminar flame. To this end, molecular dynamics simulations will be carried out to determine the competition between physical absorption of polycyclic aromatic hydrocarbons and surface chemical growth of C1-C4 species. Initial thermodynamic conditions will be defined on the basis of CFD simulation results obtained for flames studied at the EM2C laboratory.

Activités

The various tasks are :
- Analysis of scientific literature.
- Introduction to molecular dynamics simulation.
- Simulation of a TiO2 particle.
- Identification of the main mechanisms of carbon layer growth.
- Parametric studies of local conditions to establish macroscopic laws for integration into CFD codes.

Compétences

Applicants for a postdoctoral position must hold a PhD in the fields of energy/nano-materials/chemistry. The position requires:
- Strong skills in thermodynamics, chemistry and/or nanomaterials.
- Strong numerical skills in nanomaterials/chemistry.
- Previous experience in molecular dynamics will be a plus.
- Good oral and written communication skills in English to write reports, make presentations at conferences and write articles for scientific journals.

Contexte de travail

The creation of new materials from metal oxides, such as titanium dioxide (TiO2), is a growing market with applications in the transport, construction, energy and communications sectors. In particular, carbon-coated metal oxide (MO) core-shell nanoparticles (NPs) are of considerable interest for their photo-catalytic efficiency and energy storage properties, combining the advantages of metal oxides (good UV photocatalytic activity, low cost) with those of carbon (improved charge carrier separation, low resistance to charge transfer). For example, TiO2 nanoparticles are widely used as photocatalysts. For TiO2, photodegradation activity is only observed in the ultraviolet range, i.e. for around 5% of total solar energy. A carbon layer can then be added to the particle to activate the photocatalyst under visible light, i.e. ≈ 46% of total solar energy.
However, the presence of the carbon shell needs to be optimized, as too thick a carbon layer can block light and prevent the reagent from accessing the metal oxide core, thus drastically reducing the photocatalytic effect. Thus, our ability to use flames to fabricate MO@Cs with well-defined characteristics (morphology, crystalline structure, size of the metal oxide core, thickness of the carbon shell layer) is the key to accessing cutting-edge technologies. This work will contribute to the efforts of the EM2C laboratory's Transfer Physics team in developing a numerical strategy for predicting the production of MO@C particles via flames for the creation of innovative materials.

Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.