Combustion synthesis and characterization of visible-light-driven Tm-doped ZnO nanoparticles used for photodegradation of methylene blue

Abstract

Tm-doped ZnO nanoparticles were synthesized by a tartaric acid-assisted combustion method and followed by calcination at 600oC for 2 h. Phase and morphology of as-synthesized ZnO with and without Tm dopant were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The analytical results certified that Tm3+ ions were incorporated in hexagonal wurtzite ZnO structure. The particle size of ZnO was decreased with increasing in the weight content of Tm3+ dopant because the grain boundary growth of ZnO was hindered by Tm3+ dopant. The particle sizes of ZnO, 1% Tm-doped ZnO, 3% Tm-doped ZnO and 5% Tm-doped ZnO nanoparticles are 72.09 ± 17.37 nm, 32.77 ± 11.08 nm, 23.08 ± 4.61 nm and 25.27 ± 6.03 nm, respectively. The photocatalytic activity of as-synthesized ZnO with and without Tm dopant was evaluated through the degradation of methylene blue (MB) under visible light irradiation. In this research, 3% Tm-doped ZnO nanoparticles have the highest photocatalytic activity of 97.75% under visible light irradiation within 100 min. Active spices used for degradation of MB photocatalyzed by 3% Tm-doped ZnO nanoparticles were also investigated.