Double-Hollow Au@CdS Yolk@Shell Nanostructures as Superior Plasmonic Photocatalysts for Solar Hydrogen Production

Structural engineering has proven effective in tailoring the photocatalytic properties of semiconductor nanostructures. In this work, a sophisticated double-hollow yolk@shell nanostructure composed of a plasmonic, mobile, hollow Au nanosphere (HGN) yolk and a permeable, hollow CdS shell is proposed to achieve remarkable solar hydrogen production. The shell thickness of HGN@CdS is finely adjusted from 7.7, 18.4 to 24.5 nm to investigate its influence on the photocatalytic performance. Compared with pure HGN, pure CdS, a physical mixture of HGN and CdS, and a counterpart single-hollow cit-Au@CdS yolk@shell nanostructure, HGN@CdS exhibits superior hydrogen production under visible light illumination (λ = 400–700 nm). The apparent quantum yield of hydrogen production reaches 8.2% at 320 nm, 6.2% at 420 nm, and 4.4% at 660 nm. The plasmon-enhanced activity at 660 nm is exceptional, surpassing the plasmon-induced photoactivities of the state-of-the-art plasmonic photocatalysts ever reported. The superiority of HGN@CdS originates from the creation of charge separation state at HGN/CdS heterojunction, the considerably long-lived hot electrons of plasmonic HGN, the magnified electric field, and the advantageous features of double-hollow yolk@shell nanostructures. The findings can provide a guideline for the rational design of versatile double-hollow yolk@shell nanostructures for widespread photocatalytic applications.