Abstract: The binder-free porous nanoribbon-interwoven Ir1Ru3/TiOxNy thin-film electrode were fabricated through a combined process of reduced-pressure filtration, ion exchange, thermal nitridation and impregnation reduction. Systematic investigations were conducted to elucidate the effects of microstructure and varying precious metal loadings on the catalytic activity and stability for acidic oxygen evolution reaction (OER). The charge transfer dynamics at the interface and electronic transport mechanisms in the binder-free system were comprehensively analyzed, revealing the intrinsic enhancement mechanism for OER performance. Electrochemical characterization demonstrated that the Ir1Ru3/TiOxNy thin-film electrode with a noble metal loading of 10.5 wt% exhibited outstanding OER activity with overpotentials of 199 mV, 233 mV and 368 mV at current densities of 50, 100, and 500 mA cm-2, respectively. Notably, the electrode showed exceptional stability with a minimal voltage decay rate of 0.265 mV h-1 during a 200-hour durability test at 20 mA cm-2. These performance metrics significantly surpassed those of the binder-containing Ir1Ru3/TiOxNy thin-film electrode with identical precious metal loading (278 mV@50 mA cm-2, 312 mV@100 mA cm-2, 466 mV@500 mA cm-2 and a 100-hour decay rate of 1.7 mV h-1). This study provides novel insights into the rational design of high-performance acidic oxygen evolution reaction electrodes for high current densities.

Key words: Acidic oxygen evolution reaction, Nanoribbon-interwoven structure, Porous structure, High current density