Cross-Doped Ru-Co Oxides with "Superaerophobic" Surfaces for Highly Efficient and Robust Water Splitting

The sluggish mass and electron transport kinetics, along with the adhesion of in situ formed gas bubbles on the catalyst-electrolyte contact surface, significantly impede the catalytic activity of electrocatalysts for alkaline water electrolysis. Herein, we report a facile synthetic strategy for the fabrication of Ru-Co oxide composites with cross-doped heteroatoms. This composite only requires overpotentials of 11.25±1.54 mV for HER and 193.94 ± 5.84 mV for OER to reach 10 mA cm^-2, respectively, enabling an alkaline electrolyzer at an ultralow cell voltage of 1.47 V to achieve 10 mA cm^-2 for overall water-splitting with long-term stability at mimetic industrial current density (960 h@1000 mA cm^-2). Combined experiments and theoretical calculations reveal that the electron transfer exists between Ru and Co sites across the cross-doped heteroatom, constructing a built-in electric field (BEF) that accelerates charge transport. Meanwhile, the "superaerophobic" surfaces of lotus-leaf-mimicking nanostructures enable a remarkable capability to facilitate the detachment of as-formed gas bubbles and mitigate bubble-induced mass transport limitations. This cross-doping strategy can extend to the material design of other high-performance Ru-based bimetal oxides for large-scale hydrogen production.