Investigating the bifunctionality of Platinum-Iridium Electrocatalysts during Hydrogen Starvation by operando Quick-XANES

The objective of this proposal is to provide fundamental insides into the bifunctionality and reversibility of 2 - 4 nm Pt-Ir alloy NPs during the cell reversal event. In order to understand the mechanisms at stake, we will follow the time-resolved behaviour of Pt and Ir oxidation state within the NPs in few seconds to minutes, which corresponds to the time range of the H2 starvation. Due to the close energy range for Pt (LIII 11.564 eV) and for Ir (LIII 11.215 eV), we will only evaluate the Quick-XANES data as a function of the potential. From the Quick-XANES data, PCA and LCF analysis will be performed to monitor the potential and time dependent changes in oxidation state and ligand environment of the Ir and Pt atoms in the bimetallic NPs during HOR and OER.