Efficient and durable OER electrocatalysts through vacancy engineering and core-shell structure design in acidic environment

Abstract

The electrocatalytic conversion of water into green hydrogen energy through overall water splitting advances sustainable energy goals. However, it is limited by the slow kinetics of the oxygen evolution reaction (OER) and durability challenges at high potentials. Here, we rationally develop a series of Mn-doped RuO2-coated Ru (Mn-Ru@RuO2) catalysts involving unique core-shell structures and abundant lattice distortions induced by oxygen defects. The optimal Mn-Ru@RuO2 sample demonstrated robust activity, achieving a low overpotential of 220 mV at 10 mA cm−2. Notably, this sample exhibited minimal degradation after 220 h and a 25.5-fold increase in mass activity (1.37 A mgRu−1) compared to commercial RuO2 at an overpotential of 300 mV. These results suggest that regulated oxygen deficiencies and optimal Ru3+/Ru4+ ratios facilitate the lattice oxygen oxidation (LOM) mechanism and the formation of a high concentration of ∗OH radicals, enhancing acidic OER performance. Additionally, the unique core-shell structures effectively prevent over-oxidation of the RuO2 shell, ensuring superior durability. This research not only breaks the trade-off of electrochemical activity and durability, but also provides valuable insights into the design of highly efficient and stable electrocatalysts.