Nano Si-Doped Ruthenium Oxide Particles from Caged Precursors for High-Performance Acidic Oxygen Evolution

RuO₂ is well known as the benchmark acidic oxygen evolution reaction (OER) catalyst, but its practical application has been impeded by its limited durability. Herein, it is presented that the stability of ruthenium oxide can be significantly improved by pretrapping RuCl₃ precursors within a cage compound possessing 72 aromatic rings, which leads to well carbon-coated RuO_x particles (Si-RuO_x @C) after calcination. The catalyst survives in 0.5 M H₂ SO₄ for an unprecedented period of 100 hours at 10 mA cm^-2 with minimal overpotential change during OER. In contrast, RuO_x prepared from similar non-tied compounds doesn't exhibit such catalytic activity, highlighting the importance of the preorganization of Ru precursors within the cage prior to calcination. In addition, the overpotential at 10 mA cm^-2 in acid solution is only 220 mV, much less than that of commercial RuO₂ . X-ray absorption fine structure (FT-EXAFS) reveals the Si doping through unusual Ru-Si bond, and density functional theory (DFT) calculation reveals the importance of the Ru-Si bond in enhancing both the activity and stability of the catalyst.