A Bi-doped RuO2 catalyst for efficient and durable acidic water oxidation

Ruthenium oxide-based electrocatalysts have been regarded as promising alternatives to the state-of-the-art Iridium oxide (IrO 2 ) towards acidic oxygen evolution reaction (OER). However, their practical applications of proton exchange membrane water electrolyzer (PEMWE) are severely limited by the lack of efficient strategy to balance the seesaw relation between stability and activity of ruthenium oxide (RuO 2 )-based catalysts. Herein, we report that both the activity and stability of RuO 2 can be significantly boosted though bismuth (Bi) doping. We find that the introduction of Bi can increase the initial valance state of Ru in Bi 0.15 Ru 0.85 O 2 , which can promote the activation of Ru active sites, and facilitate the reaction kinetics of acidic OER. Besides, the presence of Bi can strengthen the electron interaction to maintain the structure stability and improve the electrocatalytic performance by reducing the energy barriers and avoiding the overoxidation of active species. The obtained Bi 0.15 Ru 0.85 O 2 catalyst shows a low overpotential of 200.0 mV to reach a current density of 10 mA cm –2 under acidic media, and a long-term stability for over 100 hours. Our work provides an important inspiration to rational design RuO 2 -based electrocatalysts with high activity and durability toward acidic OER.