Hierarchical Ag3PO4@ZnIn2S4 nanoscoparium: An innovative Z-scheme photocatalyst for highly efficient and predictable tetracycline degradation

Z-scheme photocatalyst preserved with superior oxidicability is an innovative photocatalyst system that can be used for efficient photocatalytic detoxification of antibiotics. In this study, Z-scheme Ag3PO4@ZnIn2S4 photocatalyst was constructed by decorating Ag3PO4 nanoparticles on ZnIn2S4 nanoscopariums. ZnIn2S4 nanoscopariums were prepared by self-templated strategy and given hierarchical structures. The hierarchical Ag3PO4@ZnIn2S4 provides more active sites for generating photogenerated carriers and large surface area for capturing tetracycline. The study results show that Ag3PO4@ZnIn2S4 performed excellently well in the photocatalytic degradation of tetracycline and also in protecting Ag3PO4 nanoparticles from photo-corrosion. The highest removal efficiency (up to 92.3%) was achieved from the optimal composites of Ag3PO4 and ZnIn2S4. In stability tests, Ag3PO4@ZnIn2S4 did not reduce the photocatalytic activity of degrading tetracycline after five successive runs. Active radical identification proves that the transfer behavior of electron and hole over Ag3PO4@ZnIn2S4 follows a direct Z-scheme mechanism. Furthermore, the transformation pathway for degrading tetracycline was proposed by combining the Fukui index prediction with Mass Spectra identification of intermediates. This work presents in-depth sights into a regulated degradation pathway from theoretical prediction and practical identification based on innovative Z-scheme photocatalyst.