[THESIS DEFENSE] ModSpeC - Amira DJAAFRI
Soutenance de thèseDear All,
I am delighted to invite you to my PhD defense entitled:
“Time-Resolved Isotopic Exchange Analysis to Identify Fast Reaction Steps in Heterogeneous Catalysis”
The defense will take place on Tuesday, December 9th at 10:00 AM in the Petit amphitheater at the ENSCL (Building C7).
The jury of my defense is composed of:
| Pr Arnaud TRAVERT | Reviewer | LCS, Université de Caen |
| Dr Céline CHIZALLET | Reviewer | IFP énergies nouvelles |
| Pr Fabien CAN | Examiner | IC2MP, université de Poitiers |
| Dr Isabelle DE WAELE | Examiner | LASIRE, université de Lille |
| Pr Christophe DUJARDIN | Thesis Director | UCCS, Centrale Lille |
| Dr Mélissande RICHARD | Co-Supervisor | UCCS, Centrale Lille |
Key words
| Heterogeneous catalysis / Reaction mechanism / Isotopic exchange / Time resolved IR spectroscopy / Step-scan |
Summary
| The objective of this thesis is to propose and validate a new methodology for elucidating reaction mechanisms in heterogeneous catalysis through the study of the fastest elementary steps. This work is based on the original coupling between Steady-State Transient Isotopic Exchange (SSTIE) analysis and operando time-resolved infrared spectroscopy (rapid-scan and step-scan modes). The feasibility of the coupling was first demonstrated using the model reaction of CO oxidation over Pt/Al2O3, and then applied to the NO reduction by CO over Ag/Al2O3, allowing the evaluation of the method’s temporal resolution and sensitivity. Finally, the approach was employed to study the CO2 hydrogenation to methanol over Cu/ZrO2. Infrared spectral deconvolution enabled the isolation and monitoring of the dynamic behavior of surface carbonate and formate species. The kinetic constants associated with these adsorbed species were determined, revealing the high reactivity of copper-bound formates, identified as key intermediates in methanol formation. This work highlights the relevance of the SSTIE–time-resolved IR coupling as an experimental tool to directly link the dynamics of surface species with kinetic phenomena in heterogeneous catalysis |
The defense will be followed by a friendly reception in the break room of Building C3.
I look forward to seeing many of you there.
Kind regards,
Amira DJAAFRI