RuO₂/CoMo₂O_x Catalyst with Low Ruthenium Loading for Long-Term Acidic Oxygen Evolution

Abstract

We must urgently synthesize highly efficient and stable oxygen-evolution reaction (OER) catalysts for acidic media. Herein, we constructed a series of Ti mesh (TM)-supported RuO₂/CoMo_yO_x catalysts (RuO₂/CoMo_yO_x/TM) with heterogeneous structures. By optimizing the ratio of Co to Mo, RuO₂/CoMo₂O_x/TM with low Ru loading (0.079 mg/cm²) achieves remarkable OER performance (η = 243 mV at 10 mA/cm²) and high stability (300 h @ 10 mA/cm²) in 0.5 mol/L H₂SO₄ electrolyte. The activity of RuO₂/CoMo_yO_x/TM can be maintained for 50 h at 100 mA/cm², and a water electrolyzer with RuO₂/CoMo₂O_x/TM as anode can operate for 40 h at 100 mA/cm², suggesting the remarkable OER durability of RuO₂/CoMo_yO_x/TM in acidic electrolyte. Owing to the heterogeneous interface between CoMo₂O_x and RuO₂, the electronic structure of Ru atoms was optimized and electron-rich Ru was formed. With modulated electronic properties, the dissociation energy of H₂O is weakened, and the OER barrier is lowered. This study provides the design of low-cost noble metal catalysts with long-term stability in an acidic environment.

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