Correlating surface potential stability with enhanced acidic oxygen evolution reaction durability in hollow TiO2-supported Ir-Re nanocatalysts

초록

Achieving both high activity and long-term stability in the acidic oxygen evolution reaction is critical for advancing proton exchange membrane water electrolyzers (PEMWE). Here, we present an electrocatalyst comprising rhenium (Re)-doped iridium nanoparticles anchored on hollow titanium dioxide nanospheres (HT-RIO). While the hollow architecture facilitates rapid mass transport, Re doping serves as a vital electronic modulator. Through X-ray photoelectron spectroscopy, Kelvin probe force microscopy, and in-situ electrochemical atomic force microscopy, we demonstrate that Re effectively prevents the over-oxidation of Ir into unstable high-valent species, thereby mitigating surface reconstruction. Consequently, the HT-RIO catalyst exhibits superior intrinsic activity and durability, maintaining stable operation for over 160 h in 0.1 M HClO4, significantly outperforming Re-free counterparts. When integrated into a single-cell PEMWE, the HT-RIO anode achieves exceptional current densities with reduced interfacial resistance. This work establishes a dual-engineering strategy, combining structural design with electronic tuning, to overcome the intrinsic degradation of iridium-based catalysts.

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