Studies on combustion synthesized ZnO and ZnO@ZrO2 nanocomposites for dye contaminated wastewater treatment

Abstract

In this study, zinc oxide (ZnO) and zinc oxide-zirconium dioxide nanocomposites (ZnO@ZrO₂) were synthesized by a low-cost solution combustion route to study their structural, morphological, optical, and photocatalytic performance. The properties of synthesized nanocomposites were characterized by x-ray diffraction (XRD), UV–vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Phase formation and purity were confirmed using XRD and EDS. Optical absorption spectra revealed that the addition of ZrO₂ significantly affected optical absorption and band gap energy. The band gap energy increased from 3.01 to 3.24 eV with addition of ZrO₂ in ZnO. FTIR spectra confirmed the formation of ZnO and ZnO@ZrO₂. SEM micrographs showed a significant change in the morphology of the ZrO₂ addition in ZnO. BET analysis showed surface area for sample P3 ([email protected]₂) was 28.9 m²/g while for sample P1 (ZnO) was 22.5 m²/g. In addition, the photocatalytic performance of ZnO and ZnO@ZrO₂ for the decomposition of methylene blue (MB) dye was studied for all samples exposed to solar light. The effect of different contents of ZrO₂ in ZnO@ZrO₂ in terms of degradation efficiency and degradation time are described in detail. The sample P3 showed highest photodegradation efficiency of 84.52 % at degradation time of 240 minutes.