Wide-Temperature/concentration-adaptive oxygen evolution reaction catalysis on integrated hierarchical FeCoNi (Oxy)hydroxide nanotubes on Ni foam grown by a single-step process

Developing cost-effective, robust oxygen evolution reaction (OER) catalysts for water electrolysis under harsh conditions remains challenging. Here, we report a one-step scalable synthesis of monolithic hierarchical FeCoNi (oxy)hydroxide nanotubes on Ni foam (H-FCNO(OH)@NF). This integrated electrode achieves exceptional OER robustness across a wide-temperature range (25-90 °C) and concentrated alkaline electrolytes (5–30 wt% KOH), delivering a low overpotential of 310 mV at 100 mA cm −2 and maintaining > 12 h stability at 100 mA cm −2 . Mechanistic studies reveal that Fe 3+ /thiourea co-mediates nanotube formation, while Co dopant-driven crystallization directs vertical nanosheet assembly. A full characterization on the catalyst after activation confirms preserved nanotube morphology, directly correlating structural integrity with catalytic durability. This work provides a facile, scalable route toward industrial-compatible OER electrodes for sustainable hydrogen production.