Monitoring Catalytic reactions on Nanoparticles by solid state NMR: a joint experimental and theoretical approach

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The project aims at studying the surface reactivity of metal nanoparticles (Ru, Pd, Au, RuCu) prepared from organometallic precursors and accommodating or not ancillary ligands (phosphines and N-heterocyclic carbenes) towards representative catalytic reactions, namely i) CO oxidation as a well-documented example, ii) arene hydrogenation for colloidal catalysis and iii) Fischer- Tropsch synthesis (FTS) for large scale heterogeneous catalysis. The course of the reactions will be monitored by various NMR experiments. Gas phase NMR, associated with mass spectrometry, will be used to characterize the course of reactions and the products in cases i) and iii) whereas solution NMR (including DOSY) will be used in case ii). The surface species, their location and dynamics will be characterized by solid state NMR. More precisely, surface deuterides location and dynamics will be achieved by temperature dependant static solid state NMR. 13CO will be used as a probe molecule to locate ancillary ligands, to determine directly or by selectively poisoning the reactions sites and to monitor the reactivity of the particles towards CO oxidation and Fischer-Tropsch Synthesis. For this purpose, variable temperature 13C MAS-NMR spectroscopy will be used. These experiments will be carried out in close interaction with a theoretical approach using DFT methods to locate the ligands and determine the reactions pathways on realistic models (Ru55). This will help both to validate experimental results (for example deuterium location) and understand the behavior of the adsorbates in order to propose a model of the catalytic reactions.