Cerium doping modulates the surface electronic structure of IrOx/TiN to promote the stability of acid oxygen evolution

The stability of supported Ir-based catalysts in acid oxygen evolution reaction (OER) remains a pressing challenge, which hinders the commercial viability of proton exchange membrane water electrolysis (PEMWE) technology. Herein, we propose a cerium doping strategy to enhance the stability of supported Ir-based catalyst toward OER. The Ce-doped supported catalysts, designated as Ce-IrO x /TiN, were synthesized using an organic colloidal method. Transmission Electron Microscopy (TEM) analysis reveals highly dispersed IrO x nanoparticles averaging 1.5 nm on the TiN support. X-ray Photoelectron Spectroscopy (XPS) investigations further elucidate that Ce doping effectively stabilizes the Ir species predominantly in states below 4 + , crucial for modulating the surface electronic structure and thereby improving both the activity and stability of the catalysts. Electrochemical characterization highlights the superior performance of the optimized catalyst, 6 %-Ce-IrO x /TiN, with an impressively low overpotential of 242 mV at 10 mA cm −2 and a Tafel slope of 57.5 mV dec −1 , showcasing its significance in facilitating OER. Moreover, its mass activity surpasses that of commercial IrO 2 by 5.1 times at 1.7 V. Prolonged constant current testing further demonstrates the exceptional stability of the catalyst, affirming the critical role of Ce doping as a pivotal strategy for enhancing the stability of supported Ir-based catalysts and advancing the prospects for robust OER performance in PEMWE systems.