Effect of alkaline earth metal doping on the stability of Ir-based catalysts

We have recently been investigating a series of Ba- and Sr-doped IrO2 oxides that demonstrate exceptional oxygen evolution reaction (OER) activity and stability in acidic environments. Our study involves a combination of in-situ spectroscopic analysis and post-performance characterization to identify the species responsible for these properties. In-situ infrared (IR) spectroscopy suggests that the OER mechanism in Ba- and Sr-doped IrO2 involves the co-adsorption of two water (H2O) molecules onto neighbouring Ir atoms, followed by a sequence of deprotonation reactions that ultimately release oxygen (O2). Since this pathway is related to the Ir-O and Ir-Ir bond distances, we propose conducting operando NEXAFS and EXAFS at the Ir L-edge to monitor the changes in these bond lengths under OER conditions, aiming to confirm the potential mechanism of oxygen evolution in these iridium-based oxides.