Electricity-driven water splitting (2H2O → 2H2 + O2) is of importance to facilitate the storage of electrical energy in the form of hydrogen fuel (H2), which is considered especially promising for global decarbonization. Despite its prospect, hydrogen production via water splitting still faces several fundamental challenges that limit the costeffectiveness. Asthe anodic half reaction, the oxygen evolution reaction (OER) isthe major bottleneck due to its sluggish kinetics and lack of active catalysts with long-lasting stability.