Tristan ASSET (futur CR au sein de l'ICPEES) présentera un séminaire intitulé : 'Electrocatalysis with single metal atom sites in doped carbon matrices' le 9 juillet 2021 à 10h en salle de réunion du R3N1

This presentation aims to provide insights, focused around recent results, on metal-nitrogen-carbon electrocatalysts synthesis, activity for the oxygen and CO2 reduction reaction and stability during operation. Metal-nitrogen-carbon electrocatalysts consist of carbonaceous structures doped with nitrogen into which are embedded single metallic atoms. They act as a suitable alternative to platinum based electrocatalysts for the oxygen reduction and are promising electrocatalysts for the synthesis of syngas, i.e. a CO + H2 mix generated by the CO2 reduction. Most often, metal-nitrogen-carbon are synthesized using a pyrolysis process, the main variations arising in the nature of the precursors and the absence, or presence, of a second pyrolysis to finely tune the physico-chemical properties of the electrocatalyst. Due to their wide variety of sites, i.e. not only metal atoms surrounded by nitrogen atoms (M-N4, M-N2+2, etc.) are found the metal-nitrogen-carbon structure, but also nitrogen based moieties, such as N-pyridinic, N-pyrrolic, etc., they are presenting various mechanisms and products for the reactions they are active for. Furthermore, the atomic nature of their main active sites and their overall carbon-like structure induces several degradation processes, e.g. (i) the ones that are similar to those observed on carbon-supported electrocatalysts, namely carbon complete and incomplete corrosion, demetallation but also (ii) ones that are specific to metal-nitrogen-carbon catalysts, i.e. cluster and nanoparticles formation, and modification of the electronic structure near the catalytic side.