Amplified Interfacial Effect on Atomically Dispersed RuOx-on-Pd 2D Inverse Nanocatalysts for High-Performance Oxygen Reduction.

Atomically dispersed oxide-on-metal inverse nanocatalysts provide a practicable blueprint to amplify the strong oxide-metal interactions for heterocatalysis but remain a grand challenge in fabrication. Here we report a 2D inverse nanocatalyst, named RuOx-on-Pd nanosheets, by in-situ creating atomically dispersed RuOx/Pd interfaces densely on ultrathin Pd nanosheets via a one-pot synthesis. The products deliver unexpected performance toward oxygen reduction reaction (ORR) in alkaline, which represents 8.0- and 22.4-fold enhancements in mass activity compared to the state-of-the-art Pt/C and Pd/C, respectively, showcasing an excellent Pt-alternative cathode electrocatalyst for fuel cells and metal-air batteries. Density functional theory calculations validate that the RuOx/Pd interfaces can accumulate partial charge from the 2D Pd hosts and subtly change the adsorption configuration of O2 to facilitate the O-O bond fracture. Meanwhile, the d-band center of Pd nanosubstrates is factually down-shifted for weakening the oxygen binding strength, tandemly motivating the excellent ORR catalysis on the RuOx-on-Pd nanosheets.