Structured catalytic nanoparticles and method of preparation

A method for forming a structured doped cerium oxide nanoparticle including the steps of forming a first aqueous cerium(lll) reaction mixture, with optional metal/s other than cerium, a base, and a stabilizer; introducing an oxidant to singly oxidize cerium (III), followed by thermal formation of a doped cerium oxide nanoparticle core; then providing a second reaction mixture of one or more metal ions other than cerium, and optionally cerium (III) ions and sufficient cerium (III) oxidant, followed by thermally converting the mixture into a shell around the doped cerium oxide nanoparticle core, wherein the ratio of metal ions in the core differs from the ratio of metal ions in the shell. The disclosed structured doped cerium oxide nanoparticle may exhibit cubic fluorite crystal structure and possess a diameter in the range 1 nm-20 nm. A dispersion of the developed nanoparticle may be used as a fuel additive.