Interface Charge Engineering of Ternary RuCoMo Oxide Nanofibers toward High-Current-Density Water Electrolysis

Abstract

The efficacy of RuO2 as a bifunctional electrocatalyst for alkaline water electrolysis is usually constrained by its sluggish hydrogen evolution kinetics and poor stability. Herein, we report the fabrication of ternary RuCoMoOx nanofibers (NFs) incorporating oxide heterojunctions, which address these issues through interfacial charge engineering. The electron redistribution induced by the constructed interface optimizes the local electronic environment, endowing the catalyst with superior activity and stability for both the hydrogen and oxygen evolution reactions (HER/OER). The RuCoMoOx NFs achieve ultralow overpotentials of 274.8 mV for HER and 367.9 mV for OER to deliver a high current density of 1 A cm−2, surpassing commercial Pt/C and RuO2 benchmarks. Moreover, the catalyst possesses superior operational stability for both HER and OER at 1 A cm–2 compared to Pt/C and RuO2, respectively. In a practical electrolyzer, the assembled symmetric RuCoMoOx NFs||RuCoMoOx NFs system delivers a much lower working voltage than Pt/C||RuO2 and maintains stable operation at 1 A cm−2 for 60 h. This work validates interfacial charge engineering as a key strategy for creating high-performance noble‑metal‑lean electrocatalysts for industrial water electrolysis.