H2WO4•H2O/Ag/AgCl Composite Nanoplates: A Plasmonic Z-Scheme Visible-Light Photocatalyst

The Z-scheme has been proven to be an effective strategy to develop a high-efficiency visible-light photocatalyst. However, the visible-light-responding active component in the Z-scheme system is usually restricted to semiconductor materials sensitive to visible light. On the other hand, noble-metal nanoparticles (such as Ag) can act as an active component for the design of high-efficiency plasmonic photocatalysts due to their strong absorption in the visible light region. In this study, H2WO4 center dot H2O/Ag/AgCl composite nanoplates were prepared by a one-step ionic reaction between Ag8W4O16/Ag nanorods and HCl aqueous solution. The photocatalytic activity experiments indicated that the H2WO4 H2O/Ag/AgCl composite nanoplates exhibited a much higher photocatalytic activity than the one-component (H2WO4 center dot H2O) or two-component (such as Ag/AgCl and H2WO4 center dot H2O/Ag) photocatalysts. On the basis of photocatalytic activity and band structure analysis, a plasmonic Z-scheme photocatalytic mechanism is proposed; namely, two-step visible-light absorption is caused by the localized surface plasmon resonance of metallic Ag nanoparticles and the band gap photoexcitation of H2WO4 center dot H2O. The present results suggest that metallic Ag nanoparticles can act as an effective active component for the construction of a Z-scheme visible-light photocatalyst. Considering the versatility and flexibility of noble-metal nanoparticles and semiconductors, this work may provide some insight into the design of novel and highly efficient Z-scheme visible-light photocatalysts.