A Functionally Stable RuMn Electrocatalyst for Oxygen Evolution Reaction in Acid

Abstract Proton exchange membrane water electrolysis (PEMWE) is a key technology to solve the serious energy and environmental problems. However, the poor durability of electrocatalysts in acidic oxygen evolution reaction (OER) environment hinders the large‐scale application of PEMWE. Herein, a robust RuMn electrochemical catalyst with a remarkable durability within 20 000 cyclic voltammetry cycles is reported. Furthermore, RuMn is stable for 720 h at 10 mA cm –2 current density in 0.5 M H 2 SO 4 solution with <100 mV overpotential increase, outperforming the most electrocatalysts reported to date, by far. An amorphous RuO x shell is detected after the OER test, indicating a surface reconstruction process on the catalyst that inhibits steady‐state dissolution. Further study demonstrates that the excellent durability of RuMn realized by protective RuO x can be attributed to strong bond strength of Ru, which is supported by density functional theory calculations with high dissolution voltage. Thus, improving the bond strength of Ru extends the design strategy for the Ru‐based alloy catalysts with considerable stability.