Year: 2026
Type: preprint
Abstract: Zirconium oxynitride (Zr2ON2) has been proposed as a support material for iridium-lean oxygen evolution reaction (OER) catalysts, with Zr2ON2 representing a middle ground between conductive but readily oxidized ZrN and acid-stable but insulating ZrO2. Using density functional theory (DFT), we assess the stability of Zr2ON2 under operating conditions and consider it as a host for singleatom Ir catalysts. Substituting Ir into the Zr2ON2(111) surface creates active sites with theoretical OER overpotentials as low as 0.31 V, aided by a stabilization of the OOH∗ intermediate. Although Zr2ON2 is stable, or at worst marginally metastable, on the Zr–N–O convex hull, computational Pourbaix analysis shows it to be unstable in aqueous environments across pH and potential. These conditions drive N to leave as N2 or as dissolved species, leaving behind either dissolved Zr or ZrO2. Previously reported stable operation of Zr2ON2-based electrodes may therefore be reconciled with a self-passivating ZrO2 surface layer.
Source: ChemRxiv
Institution: Technical University of Denmark
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: green
Funder: European Commission
OpenAlex ID: W7213466115