Optical application of Er-doped ZnO nanoparticles for photodegradation of direct red - 31 dye

Nowadays, growing world increasing demands of synthetic organic dyes which are widely used in food, leather and textile industries. This paper reports the simple rapid synthesis of Er doped ZnO nanoparticles by simple combustion method. Herein, different concentrations of Er (2.0 at. wt%, 2.5 at. wt %, 3.0 at. wt%, 3.5 at. wt%) were used as dopants. The synthesized nanoparticles were characterized in term of structural, morphological, optical and kinetic properties. These detailed characterization study confirmed that the prepared nanoparticles are well crystalline. It was observed that different concentration of Er greatly influences morphology, band gap and photocatalytic activity on ZnO nanoparticles. The prepared Er doped samples were used as photocatalyst for photodegradation of direct red 31 (DR-31) dye. From the photocatalytic experiment it was observed that the degradation percentage increases with increasing Er concentration up to 2.5 at. wt% and thereafter photocatalytic degradation was decreased. Thus the optimum concentrations of prepared nanoparticles (2.5 at. wt%) are exhibiting almost complete degradation only in 60 min under UV irradiation. Kinetic studied revealed that all the samples follows first order rate constant.