Role of oxygen vacancies on photo-catalytic activities of green synthesized ceria nanoparticles in Cydonia oblonga miller seeds extract and evaluation of its cytotoxicity effects

Ceria nanoparticles (CN) were produced via green route in Cydonia oblonga miller (Corn) seeds extract as capping and stabilizing agent. They were characterized by a variety of physico-chemical methods such as XRD, FT-IR, UV-Vis, FESEM, TGA/DTA, and photoluminescence (PL). Crystalline size of CN was increased with ascending the calcination temperature while band gap energy of them was descending from 2.4 to 3.1 eV. Cell viability was determined by MIT assay and results showed that CN had no significance toxicity on A549 cell line. Also, antioxidant effect of CN on the same cell line was performed via 2',7' -dichlorofluorescin diacetate (DCFDA). All concentration of CN specially 15.6 mu g/ml could neutralize the oxygen reactive species (ROS). Photo-catalytic study was performed to evaluate dyes degradation ability of CN under UV-A irradiation. Results illustrated that samples calcined in lower temperature showed better photo-catalytic activity. Also, PL study showed that the photoluminescence emission intensity of samples was diminished with increasing the calcination temperature. In conclusion, enhance the photocatalytic activity and photoluminescence emission was related to presence of oxygen defects in CN structure which were increased in lower calcination temperature and responsible for improving the optical properties of CN. (C) 2019 Elsevier B.V. All rights reserved.