Yi, Gyu Seong Jeong, Hui-Yun Oh, Jinho Yoo, Sung Jong Sung, Yung-Eun Park, Hyun S. 2026-05-11T09:30:06Z 2026-05-11T09:30:06Z 2026-05-07 2026-09 0926-3373 https://pubs.kist.re.kr/handle/201004/154735 The high cost and limited availability of iridium restrict large-scale deployment of proton-exchange-membrane water electrolyzers (PEMWEs). Addressing this challenge requires maintaining electronic connectivity and catalytic activity at low Ir loadings. This study introduces an ionomer-free, iridium nanotube (IrNT) network that forms a contiguous one-dimensional electronic scaffold coated onto a titanium porous transport layer. IrNTs reach electrical percolation at an order-of-magnitude lower loading than IrO2 nanoparticles (Lc = 31.3 vs. 350.1 µg cm⁻²), boosting current distribution and Ir utilization at ultralow loadings. This enables mass activity to maximize at 50 µg cm−2, reaching 79.03 A mg−1. Durability testing up to 960 h identifies a two-step degradation pathway: (i) nanotube-to-nanoparticle morphological deformation that primarily elevates mass-transport resistance, followed by (ii) rapid failure via catalyst detachment once the entangled network collapses. Importantly, a distinct mechanical percolation threshold (≥125 µg cm−2) is required to suppress detachment. A practical loading window near 300 µg cm−2 balances utilization and longevity (45.5 µV h⁻¹ over 720 h at 1 A cm⁻²). These results establish electronic and mechanical percolation thresholds as quantitative descriptors for PEMWE catalyst layers and reveal design principles—junction-rich 1D networks, sufficient aspect ratio, and controlled wall thickness—to achieve Ir-lean, durable PEMWE anodes. English Elsevier BV Percolation-driven iridium nanotube network linking utilization and durability for oxygen evolution electrode in proton exchange membrane water electrolysis Article 10.1016/j.apcatb.2026.126744 1 Applied Catalysis B: Environment and Energy, v.393 Applied Catalysis B: Environment and Energy 393 Y scie scopus 001738410400001 2-s2.0-105034632208 Chemistry, Physical Engineering, Environmental Engineering, Chemical Chemistry Engineering Article OXIDE LOADINGS PERFORMANCE IRO2 GAS CONDUCTIVITY ANODES SILVER FILMS Proton exchange membrane water electrolysis (PEMWE) Oxygen evolution reaction (OER) Iridium nanotube network Electronic and mechanical percolation Ionomer-free anode Ir utilization-durability trade-off