Synthesis of Pr-doped ZnO nanomaterials and their photocatalytic application for methylene blue degradation

Abstract

Praseodymium (Pr)-doped ZnO nanoparticles were successfully synthesised via a precipitation method and calcined at 900, 1000, and 1100°C to investigate their photocatalytic activity for the degradation of methylene blue (MB) under sunlight. The properties of the doped ZnO nanoparticles were determined using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FESEM), and UV-Vis absorption spectroscopy. FTIR and XRD analyses confirmed the presence of Pr-O bonds with wurtzite ZnO as the major phase and Pr6O11 as the dispersed phase. FESEM observations showed that the nanoparticles were smaller than 100 nm; however, particle aggregation still occurred after calcination. The photocatalytic efficiency of both pure ZnO and Pr-doped ZnO nanoparticles decreased as the calcination temperature increased from 900 to 1100°C. ZnO doped with 0.5 wt.% Pr and calcined at 900°C exhibited the highest photocatalytic activity, achieving 99.0% MB degradation after 5 h of solar irradiation. These findings demonstrate that Pr doping is an effective strategy for improving the photocatalytic activity of ZnO nanoparticles under solar irradiation.