Boosting electron transfer by coupling Ag NPs and direct Z-scheme heterojunction in Fe3O4@SiO2@ZnO-PDA-Ag for enhanced photocatalysis

Coupling Ag NPs and direct Z-scheme heterojunction in Fe 3 O 4 @SiO 2 @ZnO-PDA-Ag photocatalysts (FSZ-PDA-Ag) were constructed via the self-polymerization of dopamine. The effects of the loading amounts of Ag NPs on the structure, morphologies, and properties of the photocatalysts were investigated. Under ultraviolet and visible light irradiation, FSZ-PDA-Ag5 exhibited superior photocatalytic activity for tetracycline degradation. Direct Z-scheme ZnO-PDA heterojunction formed in FSZ-PDA-Ag could promote the transfer efficiency of electrons, and then inhibit the recombination of photo-generated charges. Meanwhile, the appropriate load of Ag NPs acted as another conductive channel to further facilitate the electrons transfer , which could extend the lifetime of the photo-generated charges. Thus, the multiple pathways of electrons transfer resulted in the enhanced photocatalytic activity , the degradation mechanism of FSZ-PDA-Ag5 was explored in detail. Moreover, this photocatalyst possessed superior cycling stability and reusability for the wastewater purification. This study may provide a reference for designing efficient and stable photocatalysts.