Low Ru loading RuO₂/(Co,Mn)₃O₄ nanocomposite with modulated electronic structure for efficient oxygen evolution reaction in acid

Oxygen evolution reaction (OER) in acidic media usually requires a catalyst with high content of noble Ir or Ru, becoming a bottleneck for the electrochemical water splitting. To address this issue, here we report the fabrication of a RuO₂/(Co,Mn)₃O₄ nanocomposite with low Ru loading (2.51 wt%) as a highly efficient OER catalyst in acidic media (0.5 M H₂SO₄). Spectroscopic and theoretical studies demonstrate that the introduction of Mn in Co₃O₄ results in redistribution of electrons and the generation of electron-rich Ru species of the RuO₂/(Co,Mn)₃O₄ catalyst. With modulated electronic properties, the adsorption of O on RuO₂/(Co,Mn)₃O₄ is weakened and the rate determining step, formation of OOH*, of the OER process is therefore accelerated. At such a low Ru loading, RuO₂/(Co,Mn)₃O₄ exhibits superior acidic OER activity (η =270 mV at 10 mA/cm²) and long‐term stability to the benchmark RuO₂ catalyst. This work provides a new strategy for the design of cost-effective acidic OER electrocatalysts for energy conversion applications.