Surface-Diffusion-Induced Amorphization of Pt Nanoparticles over Ru Oxide Boost Acidic Oxygen Evolution.

Phase transformation offers an alternative strategy for the synthesis of nanomaterials with unconventional phases, allowing us to further explore their unique properties and promising applications. Herein, we first observed the amorphization of Pt nanoparticles on the RuO 2 surface by in situ scanning transmission electron microscopy. Density functional theory calculations demonstrate the low energy barrier and thermodynamic driving force for Pt atoms transferring from the Pt cluster to the RuO 2 surface to form amorphous Pt. Remarkably, the as-synthesized amorphous Pt/RuO 2 exhibits 14.2 times enhanced mass activity compared to commercial RuO 2 catalysts for the oxygen evolution reaction (OER). Water electrolyzer with amorphous Pt/RuO 2 achieves 1.0 A cm -2 at 1.70 V and remains stable at 200 mA cm -2 for over 80 h. The amorphous Pt layer not only optimized the *O binding but also enhanced the antioxidation ability of amorphous Pt/RuO 2 , thereby boosting the activity and stability for the OER.