Exploring the Photoluminescence Property, Photocatalytic Efficiency, and Antibacterial Activity of Eu-Doped ZnO/SnO2 Heterostructure

Abstract

In this study, nanocomposites of ZnO–SnO2 doped with Eu ions were synthesized by sol-gel method. The samples show the co-existence of hexagonal ZnO and tetragonal SnO2 crystallographic phases as observed from X-ray diffractometry studies. Eu doping facilitates the grain growth as the average grain size is found to increase with the increase in Eu dopant concentration. Surface morphology of the samples also gets altered with Eu doping with EDAX measurement giving the confirmation of existence of elements like Zn/Sn/Eu. FTIR measurement specifies the appearance of peaks linked with functional groups like Zn–O, Sn–O and O–H. Photoluminescence study shows the evolution of characteristic emissions of Eu ions (5D0→ 7F1, 5D0→ 7F2 and 5D0→ 7F3). Photodegradation of toxic environmental dyes like Congo red and methylene blue was executed and the efficiency of degradation was estimated under visible light illumination. The presence of Eu3+ ions in ZnO/SnO2 helps to enhance the degradation efficiency by facilitating to form Z- scheme heterojunctions between ZnO and SnO2. This allows the delay in recombination rate of the photoinduced electron/hole pairs. The antibacterial behavior of the prepared nanocomposites against E. coli and S. aureus has also been studied in detail which demonstrates improved antibacterial efficiency of the samples.