Preparation of magnetic CuO/Fe3O4/ZnO photocatalyst for complete degradation of methylene blue under natural sunlight irradiation

A ternary CuO/Fe3O4/ZnO photocatalyst was successfully produced using a low-temperature hydrothermal method. Subsequently, the prepared photocatalyst was used to degrade Methylene Blue (MB) dye under natural sunlight irradiation. In this system, the catalyst gained magnetic properties by incorporating Fe3O4 in the ZnO nanostructure. However, the resulting photocatalytic performance was reduced, compared to the bare ZnO. To remedy this issue, a p-type CuO semiconductor was coupled to form a p-n junction between CuO and ZnO. The optimal content of CuO was 0.3 mole percent. The ternary CuO/Fe3O4/ZnO composite enhanced the removal efficiency (100%), while the mineralization was about 51.4% within 50 min under sunlight irradiation in a neutral medium. The as-prepared catalyst retained its efficiency to degrade MB dye and remained highly stable, even after six consecutive cycles. The degradation mechanism was investigated based on identifying the degradation products using liquid chromatography-mass spectrometry.