Multi-modal approach probing noble-metal catalysts at work

Abstract

Heterogeneous catalysts are by far not materials with static surface and bulk structures. They may change their structure (morphology or composition of the surface) depending on the local reaction conditions in the reactor. Especially changes on the atomic level induce changes of the chemical properties. It is crucial to have a better comprehension of the structure-function relationships. Nowadays, with the development and improvement of synchrotron radiation facilities, the interest of applying complementary in situ/operando synchrotron techniques is growing. The in situ approaches are presented as scale dependent methods and have scarcely been exploited at a multiscale level although mechanisms of activation/deactivation need to be identified at different scales. The novelty of this project consists on the combination of in situ space and energy resolved techniques to obtain complete characterisation of relevant catalytic materials under realistic working conditions. We are focused on the comprehension of elementary catalysis processes (CO oxidation reaction...) from the particle to the reaction scales. By doing in situ X-ray absorption spectroscopy and X-ray imaging studies, we will obtain information about the reaction mechanisms. With the emerging coherent X-ray imaging techniques, we can follow the structural evolutions at the single-nanoparticle-level. Strains and defects changes on the catalysts occurring through the reaction will be deeply scrutinised and linked to the catalytic performances with specific conditions of hysteresis and oscillatory behaviour, poisoning... This research project will directly generate a new methodology for the in situ monitoring of catalysts and open a new route for the research and development of materials with applications in various domains. (AU)