Amplified Interfacial Effect in an Atomically Dispersed RuOx‐on‐Pd 2D Inverse Nanocatalyst for High‐Performance Oxygen Reduction

Abstract Atomically dispersed oxide‐on‐metal inverse nanocatalysts provide a blueprint to amplify the strong oxide–metal interactions for heterocatalysis but remain a grand challenge in fabrication. Here we report a 2D inverse nanocatalyst, RuO x ‐on‐Pd nanosheets, by in situ creating atomically dispersed RuO x /Pd interfaces densely on ultrathin Pd nanosheets via a one‐pot synthesis. The product displays unexpected performance toward the oxygen reduction reaction (ORR) in alkaline medium, which represents 8.0‐ and 22.4‐fold enhancement in mass activity compared to the state‐of‐the‐art Pt/C and Pd/C catalysts, respectively, showcasing an excellent Pt‐alternative cathode electrocatalyst for fuel cells and metal–air batteries. Density functional theory calculations validate that the RuO x /Pd interface can accumulate partial charge from the 2D Pd host and subtly change the adsorption configuration of O 2 to facilitate the O−O bond cleavage. Meanwhile, the d‐band center of Pd nanosubstrates is effectively downshifted, realizing weakened oxygen binding strength.