Low-Iridium Containing Ir–Ru–W Nanocomposite for Acidic Oxygen Evolution Reaction: The Role of Tungsten on Its Activity and Stability

Iridium oxide-based electrocatalysts are widely considered as the most practical anodic catalysts for proton exchange membrane water electrolysis (PEMWE) due to their high activity as well as their exceptional stability in the acidic oxygen evolution reaction (OER). However, their use on a large scale is limited by the high cost and limited reserves of iridium metal. Herein, we present a IrRuW-based mixed oxide material containing a relatively modest iridium content of 23 atom % with respect to the total metal amount. The morphological, structural, and textural properties of the freshly prepared material were investigated by X-ray diffraction (XRD), N2 physisorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) techniques. The material, tested in rotating disk electrode (RDE) half-cell experiments, exhibited improved OER electrocatalytic performance in HClO4 0.1 M (i.e., −80 mV potential at 10 mA/cm2) compared to IrO2 and IrRuOx, respectively, used as benchmark catalysts. The electrocatalytic performances of the trimetallic system were then studied in a lab-scale and up-scaled industrial PEMWE cell setup, confirming its applicability in real flow-cell setups: a stable 2.05 V for over 500 h of utilization at 0.8 A/cm2 was registered. XRD, TEM, and inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis of the postcatalysis IrRuWOx and IrRuOx systems, respectively, pointed out the beneficial effect of the presence of tungsten on the final structural stability/durability of the material, together with no Ru leaching for the trimetallic system.