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

Abstract

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.