Zirconium-Doped Co₃O₄ for Enhancing the Acidic Oxygen Evolution Reaction by Triggering the Lattice Oxygen-Mediated...

Developing high-performance electrocatalysts for the oxygen evolution reaction (OER) in an acidic environment is crucial for practical application in proton exchange membrane water electrolyzers (PEMWE). Due to its favorable performance in an acidic environment, spinel-type Co₃O₄ has drawn considerable attention, although it remains inferior to precious metal-based electrocatalysts. In this study, we demonstrate that the catalytic activity and stability of Co₃O₄ can be enhanced by doping Zr into the octahedral interstices of Co₃O₄, which effectively triggers the fast lattice oxygen-mediated mechanism (LOM). Thus, as-fabricated Zr-doped Co₃O₄ (Zr_xCo_3-xO₄) exhibits efficient activity and fast kinetics in an acidic OER. Zr_xCo_3-xO₄ demonstrates excellent stability by maintaining a current density of 100 mA cm^-2 for 60 h. In addition, in situ electrochemical tests and theoretical calculations prove that doping Zr into the lattice of Co₃O₄ can enhance the hybridization of the Co d and O p orbitals. This significantly optimizes the adsorption of intermediates during the AEM pathway and further triggers the LOM pathway, ultimately facilitating the OER process.