Controlled doping through solubility product constant dependent Ostwald ripening for screening highly active hollow ceria nanoparticles

Hollowing and doping are two important technologies to improve the performance of nanoparticles. Ideally, doping the hollow nanoparticles can generate synergistic effect of these two technologies. However, this strategy is challenged by low doping content and/or loss of hollow structure. Herein, a method following Ostwald ripening pathway is developed to synthesize hollow ceria nanoparticles. Sixteen ions are selected to dope the nanoparticles with aim to find out how the Ostwald ripening is modulated by these ions. The results demonstrate that the solid nanoparticles formation and the central parts dissolution processes involved in the Ostwald ripening are highly dependent on the negative logarithm solubility product constant ( p K sp ) values of the doping ions. The low p K sp ions can not be easily incorporated into the solid nanoparticles thus their doping contents are low even they do not impair the central parts dissolution of the nanoparticles. In contrast, the high p K sp ions can be readily incorporated into the solid nanoparticles resulting in high doping contents, but these ions can delay the dissolution of the central parts leading to the formation of yolk-shell structures in the nanoparticles. The revealed mechanisms provide very useful information to construct doping platform for screening highly active hollow ceria nanoparticles.