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

Abstract

Three-dimensional plasmonic Ag–AgCl/γ-TaON composites have been successfully synthesized by anchoring Ag–AgCl nanocrystals on the surfaces of monoclinic γ-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 γ-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/γ-TaON composites were systematically investigated. Inspiringly, the hierarchical AgCl/Ag/γ-TaON hollow composite photocatalyst in the Z-scheme system has the superior photocatalytic performance than γ-TaON hollow spheres and conventional β-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 Ag0 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