Synthesis of ZnWO4/Ag3PO4: p-n heterojunction photocatalyst with enhanced visible-light degradation performance of RhB

A precipitation process was used to produce Ag3PO4 with an irregular small polyhedral structure and an average size of 200-300 nm. Furthermore, using a simple dissolution precipitation technique, polyhedral Ag3PO4 was successfully deposited on the surface of ZnWO4. XRD, SEM, TEM, XPS, UV-Vis DRS, and FT-IR spectroscopy were employed to analyze ZnWO4/Ag3PO4 composites. The photocatalytic oxidation ability of composites was assessed using Rhodamine B dye degradation model. The results revealed that ZnWO4/Ag3PO4 composite material displayed improved visible-light photocatalytic activity, with 7% ZnWO4/Ag3PO4 exhibiting the maximum photocatalytic activity. The degradation rate of RhB was 94.0% after 120 min of visible-light irradiation. Nyquist plot indicates that 7% ZnWO4/Ag3PO4 composites show the smallest diameter, suggesting a more effective separation of photogenerated electron-hole pairs and faster interface charge transfer. The photocatalytic activity of ZnWO4/Ag3PO4 composites does not deteriorate considerably after four cycles, indicating their high stability. The active species capture tests show that h(+) and center dot OH are possible reactive species in the degradation reaction. Finally, the p-n heterojunction mechanism is proved by the discussion of the band structure. This study demonstrates that ZnWO4/Ag3PO4 photocatalytic composites can be utilized to degrade contaminants.