Properties of Crystalline and Amorphous Transition Metal Oxides with Enhanced Fe Content as OER Electrocatalysts

Abstract

This work investigates the design of electrocatalysts for the oxygen evolution reaction (OER) using binary iron-cobaltites and ternary cobaltites containing Fe, Ni, and/or Cu, all synthesized by thermal decomposition in both the amorphous and spinel phases. The catalysts were characterized by numerous characterization methods to study their structure, composition, and morphology, while their surface area and electrochemical properties were also examined and corrected for the ohmic drop and film surface area. The catalytic activity and OER kinetics were also evaluated. Structural analysis confirmed the successful formation of amorphous and spinel oxides, where for the latter the crystallite sizes were in agreement across techniques. Electron microscopy and composition analysis demonstrated textural differences and stoichiometric consistency, while X-ray photoelectron Spectroscopy revealed distinct surface species and oxidation states. Overall, Fe incorporation enhanced the catalytic activity, whereas Ni-doping reduced the catalyst performance.