Heterostructured MgO/ZnO photocatalysts: Synthesis, Characterization and UV Light-Induced Photocatalytic Activity Using Model Pollutant 2,6-dichlorophenol

ZnO and MgO/ZnO (mass ratio 2: 5, 5: 5 and 8: 5) heterostructure photocatalysts (Mg2Zn5, Mg5Zn5 and Mg8Zn5, respectively) were successfully synthesized via co-precipitation method. MgO/ZnO composites were characterized by scanning electron microscopy (SEM), X-Ray diffraction and low temperature nitrogen adsorption-desorption isotherm. According to SEM images all composites consisted of spherical granules with particle sizes of 30-50 nm. The band gap value of ZnO was found to be lower than that of MgO/ZnO composites as observed during the optical studies. Pure ZnO showed lower photocatalytic activity (38%) in the degradation of 2,6-dichlorophenol (2,6-DCP) than MgO/ZnO composites. Mg5Zn5 composite with a higher concentration of defects in crystallites was more active in the photocatalytic degradation (79.5%) than Mg8Zn5 (61.2%) and Mg2Zn5 (63.5%). High-resolution mass spectrometry-and UV-Vis spectroscopic analysis of the by-products, derived from model pollutant 2,6-DCP, proved the successful photocatalytic performance of Mg5Zn5 under the UV light. The synthesized composites are future candidates against other potential environmental pollutants.