(560gp) In-Situ X-Ray Absorption Spectroscopy (XAS) Study on Bimetallic Iron-Nickel Based Nanoparticles for Oxygen Evolution Reaction (OER) Catalysis

Recent studies have revealed that iron-nickel based nanoparticles are excellent catalysts for oxygen evolution reaction (OER) in alkaline conditions. It is critical in the development and optimization process of catalysts to perform an in-depth characterization. We have centered this work on x-ray absorption spectroscopy (XAS); a dynamic characterization technique. XAS is divided into x-ray absorption near-edge structure (XANES) and extended x-ray absorption fine structure (EXAFS). For this research, we designed an in-situ electrochemical cell that could collect spectroscopy data on the catalysts while an electrical potential is applied. We selected two iron-nickel based nanoparticles (Fe₂₀Ni₈₀ and NiO_x – NiO_x/FeO_x) developed from varying synthesis approaches as the experimental samples and performed cyclic step chronoamperometry (CSCA) and cyclic voltammetry (CV) on the nanocatalysts in the operando cell. Fe₂₀Ni₈₀ and NiO_x – NiO_x/FeO_x have exhibited great promise as OER catalysts in our previous investigation. Therefore, the work focused on trying to understand the mechanism behind the high OER activity of the two catalysts. The role of synthesis methods on the catalytic behavior of the two nanoparticles was also investigated. XANES and EXAFS analysis also revealed additional electronic and geometric information to better comprehend the complex bimetallic nanoparticles.