Exploring the Photoluminescence Property, Photocatalytic Efficiency, and Antibacterial Activity of Eu-Doped ZnO/SnO 2 Heterostructure

Abstract

In this study, nanocomposites of ZnO–SnO 2 doped with Eu ions were synthesized by sol-gel method. The samples show the co-existence of hexagonal ZnO and tetragonal SnO 2 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 ( 5 D 0 → 7 F 1 , 5 D 0 → 7 F 2 and 5 D 0 → 7 F 3 ). 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 Eu 3+ ions in ZnO/SnO 2 helps to enhance the degradation efficiency by facilitating to form Z- scheme heterojunctions between ZnO and SnO 2 . 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. Successful preparation of Eu doped hybrid nanocomposite of ZnO–SnO 2 by sol-gel route Eu 3+ doping induced structural changes without the formation of any impurity phases Characteristic red emission linked with Eu ions are observed in PL spectra Eu-ZnO/SnO 2 shows enhanced photodegradation properties in decomposing 98.44 % and 97.33 % of methylene blue and Congo red dyes respectively in 180 minutes Superior charge separation and prohibition of e-h recombination is achieved in the heterostructure The nanocomposites also show improved antibacterial efficiency towards inhibition of E. coli and S. aureus