One-pot synthesis of Au@TiO₂ yolk-shell nanoparticles with enhanced photocatalytic activity under visible light

Natural biological systems often use hollow structures to decrease reflection and achieve high solar light utilization. Herein, bio-inspired Au@TiO₂ yolk-shell nanoparticles (NPs) have been designed to combine the advantages of noble metal coupling and hollow structures, and subsequently synthesized via a facile one-pot hydrothermal approach. The Au@TiO₂ yolk-shell NPs not only exhibit reduced reflectance by multiple reflections and scattering within the hollow NPs, but also show enhanced photocatalytic activity in Rhodamine B (RhB) degradation by simultaneously improving light harvesting, charge separation and reaction site accessibility. Specifically, compared to the commercial TiO₂ (P25), Au/TiO₂ hybrid and Au@TiO₂ core-shell NPs, the Au@TiO₂ yolk-shell NPs demonstrate lower reflectance over a broader range and superior photocatalytic activity with more than 98.1% of RhB decomposed within 4h under visible light. The bio-inspired nanostructure, as well as the facile and scalable fabrication approach, will open a new avenue to the rational design and preparation of efficient photocatalysts for pollutant removal.