The preparation temperature influences the physicochemical nature and activity of nanoceria

Beilstein Journal of Nanotechnology

article

Robert A. Yokel¹  Wendel Wohlleben²  Johannes Georg Keller²  Matthew L. Hancock³  Jason M. Unrine⁴  D. Allan Butterfield⁵  Eric A. Grulke³ 

[1] Pharmaceutical Sciences, University of Kentucky;BASF;Chemical and Materials Engineering, University of Kentucky;Plant and Soil Sciences, University of Kentucky;Chemistry, University of Kentucky

关键词: cerium;    dissolution;    nanoparticles;    physicochemical properties;    valence state;   

DOI  :  10.3762/bjnano.12.43

学科分类：环境监测和分析

来源: Beilstein - Institut zur Foerderung der Chemischen Wissenschaften

【 摘 要 】

Cerium oxide nanoparticles, so-called nanoceria, are engineered nanomaterials prepared by many methods that result in productswith varying physicochemical properties and applications. Those used industrially are often calcined, an example is NM-212. Othernanoceria have beneficial pharmaceutical properties and are often prepared by solvothermal synthesis. Solvothermally synthesizednanoceria dissolve in acidic environments, accelerated by carboxylic acids. NM-212 dissolution has been reported to be minimal.To gain insight into the role of high-temperature exposure on nanoceria dissolution, product susceptibility to carboxylic acid-accelerated dissolution, and its effect on biological and catalytic properties of nanoceria, the dissolution of NM-212, a solvothermallysynthesized nanoceria material, and a calcined form of the solvothermally synthesized nanoceria material (ca. 40, 4, and 40 nm diameter, respectively) was investigated. Two dissolution methods were employed. Dissolution of NM-212 and the calcinednanoceria was much slower than that of the non-calcined form. The decreased solubility was attributed to an increased amount ofsurface Ce4+ species induced by the high temperature. Carboxylic acids doubled the very low dissolution rate of NM-212.Nanoceria dissolution releases Ce3+ ions, which, with phosphate, form insoluble cerium phosphate in vivo. The addition of immobilized phosphates did not accelerate nanoceria dissolution, suggesting that the Ce3+ ion release during nanoceria dissolution wasphosphate-independent. Smaller particles resulting from partial nanoceria dissolution led to less cellular protein carbonyl formation,attributed to an increased amount of surface Ce3+ species. Surface reactivity was greater for the solvothermally synthesized nanoceria, which had more Ce3+ species at the surface. The results show that temperature treatment of nanoceria can produce significant differences in solubility and surface cerium valence, which affect the biological and catalytic properties of nanoceria.

【 授权许可】

CC BY