Hydrous ruthenium oxide triggers template-free and spontaneous growth of metal nanostructures.

Intrinsically conductive ruthenium oxide is an excellent material for energy storage and conversion. Herein, we present hydrous RuO 2 (H-RuO 2 ) as a potent reducing agent to achieve spontaneous growth of multiple noble metals at room temperature. Self-assembled gold and platinum, comprising small-sized nanoparticles, are generated on the surface of H-RuO 2 without the need for additional templates. Structural analysis reveals that the disordered structure and the presence of oxygen vacancies trigger interfacial redox reactions between H-RuO 2 and oxidative metal salts. The resulting integrated nanostructures, consisting of a metal oxide and different metals (H-RuO 2 @metal), are subsequently used to treat inflammatory bowel diseases. In addition to biomedical applications, our developed synthetic strategy, using reactive oxides to spontaneously generate multicomponent nanostructures, also holds great significance for other catalysis-based applications.