Characterizations of Ag doped ZnO particles via flame pyrolysis method for degradation of methylene blue

Flame pyrolysis is widely used for the fabrication of particles because of great crystallinity and fine size distribution of the products. In this research, ZnO-Ag particle materials have been favourably made by flame pyrolysis. The impacts of Ag loading varying from 0 to 20 wt% on the photocatalytic activity of ZnO-Ag particle under ultraviolet (UV) and sunlight irradiations were studied. ZnO-Ag particles were fabricated based on zinc acetate dihydrate (Zn(CH₃COO)₂.2H₂O) 0.1 M and silver nitrate (AgNO₃) as a precursor inside a flame reactor. Crystallinity and morphology of ZnO-Ag particles were identified by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. SEM analysis showed that the particles had irregular sphere-like shapes. The XRD patterns showed that the produced ZnO had a wurtzite structure with different crystallite sizes. XRD analysis also confirmed the existence of Ag particles in ZnO-Ag particles after the addition of Ag greater or equal to 5 wt%. The existence of Ag was indicated by the appearance of the XRD peak at 38.1°. The peak at 38.1° increased with the increase of Ag loading. Finally, the photocatalytic activity was evaluated by estimating the degradation of methylene blue aqueous solution under UV and sunlight irradiations. It noted that the most excellent photocatalytic performance was achieved at 5 wt% Ag loading for both irradiations. (paper)