Activating RuO2 nanofibers through precise Re doping toward promoted alkaline water electrolysis under high current density exceeding 1 A cm−2

Ruthenium dioxide (RuO 2 ) stands out as a versatile catalyst for acidic oxygen evolution reactions (OER), yet it falls short in alkaline conditions, and its hydrogen evolution reaction (HER) activity is generally lacking. This poses a significant challenge in engineering a robust bifunctional electrocatalyst capable of excelling in both alkaline HER and OER through manipulating the electronic structure of RuO 2 . Here, we have developed a nanofibrous rhenium (Re)-doped RuO 2 electrocatalyst via an electrospinning-calcination process, tailored for comprehensive water splitting applications. By finely tuning the Re doping content, the optimized Re-doped RuO 2 catalyst achieves overpotentials of merely 386 mV for OER and 157 mV for HER at a current density of 1 A cm −2 in 1 M KOH, significantly outperforming the conventional RuO 2 and Pt/C catalysts in their respective reactions. This bifunctional Re-doped RuO 2 catalyst showcases unparalleled efficiency in overall water splitting, demanding an impressively low power consumption of 6.36 kWh m −3 H 2 at the elevated current density of 1 A cm −2 , which substantially surpasses the performance of the benchmark Pt/C||RuO 2 system. Moreover, it maintains excellent stability under such demanding high current density conditions. Our research provides profound insights into the design of highly efficient RuO 2 -based catalysts, paving the way for their deployment in practical industrial water electrolysis technologies