Abstract Ruthenium (Ru) has been recognized as a prospective candidate to substitute platinum catalysts in water‐splitting‐based hydrogen production. However, minimizing the Ru contents, optimizing the water dissociation energy of Ru sites, and enhancing the long‐term stability are extremely required, but still face a great challenge. Here, we report on creating tungsten oxide‐anchored Ru clusters (Ru–WOx) with electron‐rich and anti‐corrosive microenvironments for efficient and robust seawater splitting. Benefiting from the abundant oxygen vacancy structure in tungsten oxide support, the Ru–WOx exhibits strong Ru–O and Ru–W bonds at the interface. Our study elucidates that the strong Ru–O bonds in Ru–WOx may accelerate the water dissociation kinetics, and the Ru–W bonds will lead to the strong metal–support interaction and electrons transfer from W to Ru. The optimal Ru–WOx catalysts exhibit a low overpotential of 29 and 218 mV at the current density of 10 mA cm−2 in alkaline and seawater media, respectively. The outstanding long‐term stability discloses that the Ru–WOx catalysts own efficient corrosion resistance in seawater electrolysis. We believe that this work offers new insights into the essential roles of electron‐rich and anti‐corrosive microenvironments in Ru‐based catalysts and provide a new pathway to design efficient and robust cathodes for seawater splitting.
