Synthesis and characterization of photocatalytic zinc oxide/titanium oxide (core/shell) nanocomposites

In this project, core/shell ZnO/TiO2 nanocomposite samples were prepared using the sol-gel method at different time spans. Characterization of the samples was done using X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM), as well as Raman spectroscopy. The optical properties were evaluated using UV-Vis diffuse reflectance and photoluminescence spectroscopies. The photocatalytic ability of all samples in the degradation of methylene blue (MB) dye by the radiation of Hydrargyrum medium-arc iodide (HMI) lamp was determined. The amount of charge carriers in the samples was calculated using the Mott-Schottky test. The XRD results showed that as the sol-gel preparation time increased, so did the TiO2 shell thickness and its crystallite size. The FE-SEM results revealed the spherical morphology of the samples. The sample prepared in the 15-min time span (ZnTi15) proved as the optimal sample, exhibiting 3 times more photocatalytic activity in comparison to the ZnO control sample. Also, the charge carrier density of the ZnTi15 sample was about 5 times more than that of the ZnO sample. Furthermore, the photoelectrochemical test showed a photocurrent density twice larger for the ZnTi15 sample, which could be attributed to the formation of the heterojunction at the ZnO/TiO2 interface. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this study, core/shell ZnO/TiO2 nanocomposite samples were prepared using the sol-gel method at different time spans. The sample prepared in the 15-minute time span (ZnTi15) exhibited the highest photocatalytic activity and charge carrier density, making it the optimal sample. The formation of a heterojunction at the ZnO/TiO2 interface could be attributed to the increased photocurrent density observed for the ZnTi15 sample.