Ultrafast synthesis of vacancy-rich IrO₂/TiO₂ for acidic oxygen evolution reaction

Supported catalysts are an effective approach in proton exchange membrane water electrolysis (PEMWE) owing to their enhanced metal-support interfacial interaction. We propose a novel high-temperature shock (HTS) technique by Joule-heating to construct an electronic coupling interface between IrO₂ nanoclusters catalysts and TiO₂ support (IrO₂/TiO₂-HTS). The HTS strategy features an ultrafast heating rate and compresses the synthesis time from hours to seconds (2 h to 60 s). The as-prepared catalyst features uniformly embedding the ultrafine IrO₂ nanoclusters enrich oxygen vacancies within the redox-active metal oxide matrix, yielding exceptional mass activity and ultrastable performance. The mass activity of the catalyst is 1081 A/g_Ir at 1.6 V vs. RHE, 13 times higher than of commercial IrO₂, and it demonstrates operation time for over 1100 h at 10 mA/cm² with a voltage decay rate of only 40 μV/h. This HTS strategy offers a scalable route to accelerate vacancy engineering and strong metal oxide-support interaction (SMOSI) formation, enabling high activity at reduced Ir loading and long-term stability under acidic conditions. The approach is general and can be extended to other supported binary oxides, opening opportunities for the development of additional high‑performance OER catalysts and PEM‑relevant electrolysis systems.