Construction of ZnCo2O4/Ag3PO4 composite photocatalyst for enhanced photocatalytic performance

In this study, ZnCo₂O₄/Ag₃PO₄ composite catalyst was prepared by the precipitation method, and their performance in the photocatalytic degradation of methyl orange (MO) was studied. The catalysts were characterized by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, selected area electron diffraction, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectroscopy. The results indicate that the 0.1 ZnCo₂O₄/Ag₃PO₄ composite system has good photocatalytic activity in the degradation of methyl orange. Under simulated sunlight conditions, the degradation rate can reach 94% after 30 min. The maximum reaction rate constant of 0.1 ZnCo₂O₄/Ag₃PO₄ was 0.05301 min⁻¹, which is 3 times and 52 times the rate constant of pure Ag₃PO₄ and pure ZnCo₂O₄, respectively. In catalyst recycling experiments, 0.1 ZnCo₂O₄/Ag₃PO₄ still degraded methyl orange at a rate of 84.4% after three cycles. Trapping experiments showed that holes and superoxide radicals mostly contributed to the photocatalytic degradation of methyl orange by the catalyst, while hydroxyl radicals played a partial role. The energy level structure of ZnCo₂O₄/Ag₃PO₄ is conducive to the effective separation of photogenerated electrons and holes, improving the lifespan of photogenerated charges. In the investigated catalyst series, 0.1 ZnCo₂O₄/Ag₃PO₄ demonstrated the best photocatalytic performance.