Manipulating Ru oxidation within electrospun carbon nanofibers to boost hydrogen and oxygen evolution for electrochemical overall water splitting

Abstract

Developing bifunctional electrocatalysts with high efficiency and prominent durability toward overall water splitting is a fascinating way to produce hydrogen for clean energy applications. In this work, partially oxidized Ru nanoparticles integrated within electrospun carbon nanofibers (RuO₂/Ru-CNFs) are prepared via a convenient electrospinning–carbonization–oxidation process. Benefitting from the small size of the active nanoparticles, the formation of a RuO₂/Ru heterostructure and the introduction of a carbon substrate, the optimized RuO₂/Ru-CNFs-350 catalyst delivers excellent OER and HER performances with ultralow overpotentials of 203 mV and 21 mV at 10 mA cm⁻², respectively, along with remarkable long-term stabilities under alkaline conditions. Moreover, we constructed an alkaline overall water splitting electrolyzer with RuO₂/Ru-CNFs-350 as both the anode and cathode, achieving a low working voltage of 1.452 V at 10 mA cm⁻², superior to that of the benchmark Pt/C||RuO₂ couple (1.560 V). This work provides a convenient and promising route to fabricate high-performance bifunctional electrocatalysts toward water electrolysis.