A Facile Approach to Well-Dispersible CeO2Nanoparticles

18 nm CeO2 with surface being functionalized by nitrate groups were prepared to yield a stable suspension in acidic aqueous solution. Different from the bare ones, these suspensions precipitated rapidly when the solution became basic. Further tuning the solution back to acidic led to a stable suspension again. This phenomenon was explained in terms of the electrostatic repulsion of electrical double layers of intensive surface bound nitrate groups and acidic medium.