Synthesis of samarium-doped zinc oxide nanoparticles with improved photocatalytic performance and recyclability under visible light irradiation

Abstract

Samarium-doped ZnO nanoparticles (1%, 3%, and 5%) were synthesized by a gel-combustion route and their application as an efficient photocatalyst for the degradation of Malachite green (MG) dye is demonstrated. These nanoparticles were characterized by spectroscopic techniques (UV-vis and photoluminescence), micrograph techniques (SEM and TEM), X-ray diffraction, and energy dispersive X-ray, in order to evaluate their optical and structural properties, particle size distribution, and morphology. The UV-vis spectroscopic studies indicated that Sm doping increased the visible light absorption ability of the Sm-doped ZnO nanoparticles and a redshift for the Sm-doped ZnO nanoparticles appeared when compared to ZnO nanoparticles. An enhancement in the optical absorption of the Sm-doped ZnO nanoparticles indicated that it can be used as an efficient photocatalyst under a visible light irradiation. The effect of tert-butyl alcohol and disodium salt of ethylenediaminetetraacetic acid as the scavengers in the photocatalysis process revealed that hydroxyl radicals (˙OH) and holes (h⁺) were the reactive species responsible for the degradation of MG. The degradation mechanism has been proposed for the degradation of MG dye under the visible light irradiation. The recyclability of the Sm-doped ZnO nanoparticles for the MG dye degradation is also demonstrated.