S-doped Yttrium Ruthenate Pyrochlore catalyst for Efficient Electrocatalytic Oxygen Evolution in Acidic Media

The sulfur-doped yttrium ruthenate pyrochlore catalysts was synthesized by simple hydrothermal method and exhibits excellent OER activity and stability under acidic conditions. Remarkably, the Y₂Ru₂O₇S-0.17 catalyst reaches a current density of 10 mA cm⁻² with only 237 mV and remains stable during 30 hours of electrolysis. In contrast, the original Y₂Ru₂O₇ and commercial RuO₂ require 282 mV and 365 mV, respectively. The introduction of sulfur into the internal lattice, replacing a portion of oxygen ions, creates vacancies that enhance the surface adsorption of oxygen. Furthermore, density functional theory calculations expose that S-doping alters the hybridization between the Ru 4d center and O 2p orbitals, significantly decreasing the energy barrier of the rate-determining step of the OER (O*–OOH*). Consequently, the intrinsic activity of the catalyst is greatly enhanced.