Three-dimensional Z-scheme AgCl/Ag/γ-TaON heterostructural hollow spheres for enhanced visible-light photocatalytic performance

Three-dimensional plasmonic Ag-AgCl/gamma-TaON composites have been successfully synthesized by anchoring Ag-AgCl nanocrystals on the surfaces of monoclinic gamma-TaON hollow urchin-like spheres via the deposition-precipitation method and photo-reduction process. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, Brunauer-Emmett-Teller analysis, X-ray photoelectron spectra and UV-vis diffuse reflectance spectrum. The interleaved nanoneedles assembled in the hierarchical floriated gamma-TaON hollow spheres contributed to the stable deposition of Ag/AgCl nanocrystals and the formation of effective nanojunctions. The effects of the amount of Ag-AgCl nanocrystals and the photo-reduction time upon the photocatalytic properties for the Ag-AgCl/gamma-TaON composites were systematically investigated. Inspiringly, the hierarchical AgCl/Ag/gamma-TaON hollow composite photocatalyst in the Z-scheme system has the superior photocatalytic performance than gamma-TaON hollow spheres and conventional beta-TaON nanocrystals over the degradation of rhodamine B and acid orange 7 dyes and the reduction of aqueous Cr(VI), which is attributed to the effective charge transfer from plasmon-excited Ag nanocrystal to TaON, leading to the low recombination rates of the photoinduced electron-hole pairs. X-ray photoelectron spectroscopy analyses indicated that both AgCl and Ag-0 components coexist in the system, and the as-prepared composite is relatively stable. This work could provide new insights into the fabrication of hierarchically plasmonic photocatalysts with high performance and facilitate their practical application in environmental issues (c) 2013 Elsevier B.V. All rights reserved.