Effect of high temperature annealing on the electronic structure and antioxidant properties of ablated Cerium dioxide nanoparticles

Purpose . Study of the dependence of the electronic structure and antioxidant properties of ablated cerium dioxide nanoparticles on the annealing temperature under photocatalytic reaction conditions in the presence of titanium dioxide nanoparticles. Methods . Nanoparticles of cerium dioxide were obtained by laser ablation. The average sizes of ablated nanoparticles of cerium dioxide subjected to centrifugation and high-temperature annealing were calculated from AFM images. A change in the electronic structure of annealing was detected by spectrophotometry, and sedimentation of annealed nanoparticles was studied. Also, the dependence of the antioxidant activity of cerium dioxide nanoparticles on the annealing temperature in the photocatalysis process was determined using a spectrophotometer. Results . The average sizes of ablated annealed centrifuged cerium dioxide nanoparticles were determined to be in the range from 46,3±0,5 nm to 82,8±0,5 nm. The studies revealed a bathochromic shift in the energy position of the 4f0 states of Ce4+ ions in the bandwidth of the bandgap of annealed cerium dioxide nanoparticles after annealing, and its effect on the sedimentation process of nanoparticles was not revealed. It was found that during the photocatalytic reaction in the presence of ablated annealed cerium dioxide nanoparticles, the degradation rate of the methylene blue dye increases, i.e., the antioxidant activity of CeO2 nanoparticles decreases. Conclusion : From the results of the studies presented in this paper it follows that under the influence of high-temperature annealing the physicochemical properties of ablated cerium dioxide nanoparticles change, in particular, their antioxidant activity decreases, but the sedimentation rate of nanoparticles in an aqueous solution remains constant.