Preparation and photocatalytic degradation performance of dual Z-Scheme ZnFe₂O₄/Ag₃PO₄@g-C₃N₄ composite photocatalyst

In the quest for efficient photocatalysts for environmental remediation, the development of multi-component heterojunction systems has garnered significant attention. This study synthesized a ZnFe₂O₄/Ag₃PO₄@g-C₃N₄ ternary photocatalyst by coating a graphitic carbon nitride (g-C₃N₄) layer on the outer surface of ZnFe₂O₄/Ag₃PO₄ microrod catalysts. The photocatalytic activity of the composite material was evaluated through degradation experiments of methylene blue (MB) and bisphenol A (BPA). Additionally, the performance of catalysts with different g-C₃N₄ contents was systematically investigated. The results demonstrates that the ZnFe₂O₄/Ag₃PO₄@g-C₃N₄ composite catalyst exhibits remarkable degradation performance in MB solution. When the g-C₃N₄ content is 10wt.%, the photocatalytic activity reaches its optimum, achieving a degradation rate of up to 96% for MB under visible light irradiation, following pseudo-first-order kinetics. Furthermore, significant stability is observed during cyclic operation. X-ray diffraction (XRD) patterns indicates that no Ag elemental silver is detected in the catalyst. The enhanced mechanism of the ternary photocatalytic performance can be attributed to the synergistic effect of the dual Z-scheme heterostructure formed among the three components, which facilitates the effective separation and transfer of photogenerated carriers, as well as the enhanced adsorption capacity of g-C₃N₄ that strengthens the substrate-catalyst interaction, collectively promoting the improvement of photocatalytic performance.