Optimized synthesis of ZnO nanostructures by egg-white content ratio manipulation for photocatalytic applications

Abstract

Zinc oxide nanoparticles (ZnO NPs) were prepared through a green egg-white (EW) mediated method and characterized by x-ray diffraction (XRD), Field emission-scanning electron microscopy (FESEM), Photoluminescence (PL), and ultraviolet-visible (UV–vis) spectroscopy studies. Three egg-white content to zinc nitrate ratio were applied to synthesis the ZnO structures. Crystallite size of 48, 42, and 29 nm was obtained for 1:1, 2:1, and 3:1 wt ratio of EW: Zn(NO3)2 which indicated the impact of EW concentration on ZnO NPs size. FESEM shows that EW controls the nucleation, growth, and morphology of ZnO. The sample with 2:1 wt ratio found to be the most efficient photocatalytic performance by degrading almost 99% of methylene blue (MB) within 60 min in water under natural irradiation with a pseudo-first-order rate constant of k = 5.89 × 10−2 min−1. It is demonstrated that morphology, size and surface oxygen vacancy of ZnO NPs are responsible to the efficient photocatalytic activity towards degradation of the MB dye under natural sunlight irradiation.