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

Abstract

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.