Controlled growth of AgI nanoparticles on hollow WO3 hierarchical structures to act as Z-scheme photocatalyst for visible-light photocatalysis

Controllable fabrication of nanomaterials with hierarchical architecture have received much attention in the field of photocatalysis due to their enhanced light-harvesting efficiency. Moreover, fabricating direct Z-scheme heterojunctions have   been   proven to be effective way to enhance the photocatalytic performance of photocatalysts . Herein, hierarchically hollow WO 3 nanoflower was successfully synthesized by a simple hydrothermal treatment of tungsten chloride (WCl 6 ) in ethanol solution. Decoration of the obtained WO 3 with AgI nanoparticles in situ can form the Z-scheme AgI/WO 3 hollow hierarchical nanoflowers (AgI/WO 3 HHNFs). The AgI/WO 3 HHNFs exhibited excellent photocatalytic activity and remarkable stability for the degradation of tetracycline hydrochloride (TC-HCl) and Eosin B (EB) under the irradiation of a low energy consume light (LED lamp, 5 W). Interestingly, compared to pure AgI nanoparticles , 3D hollow WO 3 nanoflowers and AgI/WO 3 nanosheets , the AgI/WO 3 HHNFs revealed conspicuously enhanced photocatalytic activity . This   phenomenon could be associated to three aspects, namely the high light-harvesting efficiency, increased light trapping and scattering capability and strongly coupled Z-scheme heterointerface, which effectively improved the photoelectron-hole sepreation efficiency. Our work therefore provide a novel insight for the fabrication of 3D hollow hierarchical structures.