Soutenance de thèse SOLEIL - David SIMONNE - Vendredi 12/01/24-14h00

Catalytic properties at the nanoscale probed by surface x-ray diffraction and coherent diffraction imaging

David SIMONNE
(Ligne SIXS, Synchrotron SOLEIL, Gif-sur-Yvette)

Vendredi 12 janvier 2024 – 14h00 - Amphithéâtre SOLEIL

The focus of this study is the investigation of heterogeneous catalysts in situ and operando during ammonia oxidation, approaching industrial temperature and pressure.
Understanding this catalytic process and its associated structural changes is currently limited.
Different platinum samples, including nanoparticles and single crystals, are employed to bridge the gap between model studies and industrial catalysts.
The catalytic activity of these samples is measured to correlate structure and selectivity, aiming for nitrogen or nitric oxide production.
The ongoing challenge is developing heterogeneous catalysis with 100% selectivity and comprehending catalyst durability, aging, and deactivation.
Nanoparticle structure analysis at the nanoscale reveals volume, surface, and interface effects, along with various defects.
Bragg coherent X-ray diffraction imaging and grazing incidence X-ray diffraction are employed to study nanoparticles. Surface X-ray diffraction and X-ray photoelectron spectroscopy allows to probe individual crystal surfaces, linking them to catalytic activity for a better understanding of the reaction mechanism.

Les membres du jury sont :
Andreas STIERLE - Pr.University of Hamburg / DESY - Rapporteur et Examinateur
Thomas CORNELIUS - DR., IM2NP, Aix-Marseille Université - Rapporteur et Examinateur
Sylvain RAVY - DR., LPS, Université Paris-Saclay - Examinateur
Gerardina CARBONE - Dr., Lund University - Examinatrice
Virginie CHAMARD - DR. Institut Fresnel, Aix-Marseille Université - Examinatrice
Alessandro COATI - Dr., Synchrotron SOLEIL - Directeur de thèse
Marie-Ingrid RICHARD - Dr., CEA Grenoble - Co-Directrice de thèse
Andrea RESTA  - Dr., Synchrotron SOLEIL - Co-encadrant de thèse