Immobilization and structural transformations of Ir-based oxygen evolution reaction catalysts supported on porous transport electrodes for proton-exchange membrane water electrolysis

The advancement of cost-effective, energy-efficient, and durable proton-exchange membrane water electrolysis (PEMWE) devices is essential for the conversion and utilization of renewable electricity. Currently, the primary contributors to the cost of PEMWE devices are noble metal catalysts and electrochemical cell modules. In this study, we have developed a straightforward method to load metal active components—both noble and non-noble metals—onto a porous titanium mesh, thereby constructing an all-in-one porous transport electrode for the oxygen evolution reaction in PEMWE devices. Utilizing porous titanium mesh as both the transport layer and the support for metal catalysts can significantly reduce the overall cost of PEMWE devices. Moreover, by developing tri-metallic Ir-Au-Sn sites on the titanium mesh, we achieve an exceptionally high specific activity of the iridium catalyst for oxygen evolution reaction (OER) in PEMWE devices, measuring 2.7 A/cm² at 2.0 V with an iridium loading of 0.14 mg/cm². We employ various electron microscopy and spectroscopy characterization techniques to explore the structural evolution of the metal sites under severe operating conditions, providing valuable insights into the nature of the active sites for OER in PEMWE and identifying potential degradation mechanisms of the materials under these conditions.