Size composition, structure and antioxidant properties of Cerium dioxide nanoparticles obtained by autoclave synthesis

Purpose of the study . To characterize the size composition, atomic and electronic structure, and antioxidant activity of Cerium dioxide nanoparticles synthesized by the hydrothermal method in an autoclave. Methods . Cerium dioxide nanoparticles were synthesized in an autoclave at 150°C. The size composition of the nanoparticles was characterized by small-angle X-ray scattering diffractometry. The structural and phase composition was studied using X-ray diffractometry. Scanning electron microscopy with an energy-dispersive X-ray analysis attachment was used to analyze the elemental composition of the samples. Antioxidant activity was studied in the photochemical degradation reaction of methylene blue dye under irradiation with a diode source with a wavelength of 660 nm. The residual concentration of methylene blue in the process of photodegradation was determined using spectrophotometry. Results . Pure Cerium dioxide nanoparticles measuring 10-25 nm were synthesized using hydrothermal synthesis in an autoclave at 150°C. In the presence of the obtained cerium dioxide nanoparticles, the process of photodegradation of the methylene blue dye under the influence of red laser radiation slows down by 80%. The addition of ammonium citrate-stabilized Cerium dioxide nanoparticles leads to a slowdown in the process of photodegradation of methylene blue under irradiation with red light due to antioxidant activity, which increases with increasing concentration of nanoparticles. Maximum antioxidant activity is manifested at a molar ratio of ammonium citrate to CeO 2 of no more than 2:1. Conclusion . The hydrothermal synthesized CeO 2 nanoparticles stabilized by ammonium citrate exhibit pronounced antioxidant activity. The results obtained can be used to develop selective antitumor photosensitizers based on Cerium dioxide nanoparticles.