Unveiling Cu and Fe local structure in bimetallic N-doped electrocatalyst by operando XAS for alkaline ORR and HER

XAS techniques have been proved to be useful for unveiling the coordination and electronic structure of metal-based electrocatalysts. Most studies usually focus on ex-situ measurements of fresh or used materials, whilst the potential-driven dynamic evolution of the active site structure during reaction is usually only addressed by theoretical calculations. We propose the use of operando XAS measurements to study the evolution of metal species (Fe, Cu, Fe-Pd and Cu-Pd) environment present in N-doped monometallic and bimetallic carbon electrocatalysts used in Hydrogen Evolution Reaction (HER) and Oxygen Reduction Reaction (ORR). The development of optimized catalysts for these electrochemical processes is considered crucial for the hydrogen strategy of European 2030 targets. We will carry out measurements at different potentials (zero-current, kinetic region and high overpotential) to get insights into the coordination numbers of the metal species, which will help to study the reaction mechanisms. Such measurements will be highly innovative, since operando XAS has never been used to study the changes in bimetallic clusters during these reactions. Samples with different metallic coordination (C3N4 and phthalocyanines) will be studied aiming to understand how the bimetallic composite materials are modified at different conditions by in-situ measurements. The results obtained from these measurements, along with the detailed characterization we have previously performed by ex-situ XAS analysis among other physicochemical techniques such as XPS, TPR, or electrocatalytic activity studies, will represent a breakthrough in the understanding of the electrocatalytic species coordinated with N and the synergetic effect between metals by studying electronic structure and coordination during reaction.