Lead is a very useful element that has found application in batteries, construction, bullets and hunting ammunition, it is part of solder and various alloys. It is especially used in piezoelectrics and as a shield against radiation. Unfortunately, lead is a potent neurotoxin that accumulates in soft tissues and bones over time. Therefore, it is of great interest to control Pb mobility and bio-accessibility by its immobilization in a suitable crystal structure. Ceria with fluorite structure could play essential roles in lead immobilization.
Nanosized Pb-doped ceria (Ce1-xPbxO2-d) powders (0.1 ≤ x ≤ 0.3)  were obtained by self-propagating room temperature reaction. The solid solubility of Pb into ceria lattice was the highest reported so far. X-ray diffraction analysis and field emission scanning microscopy results showed that the doped samples are single phase solid solutions with fluorite-type structure and all prepared powders were nanometric in size. The average size of Ce1-xPbxO2-d particles lies at about 4 nm. Raman spectra revealed an increase in the amount of oxygen vacancies with the increase of Pb concentration. The thermal stability of solid solution was followed by XRD. Microstructure development was studied by scanning electron microscopy. The mass of Pb [ppm] in the solution with different percentage of Pb in the doped ceria after its dissolution in different time intervals at pH 3, pH pH 7 and pH 11 was measured by means of Inductively coupled plasma spectroscopy (ICP). The TEM investigation showed that pattern of CeO2 before and after leaching confirms that samples are single phase CeO2. The elemental composition and change of Pb content before and after teaching is investigated by EDS. Beside the change of Pb content observed in EDS spectrum of the sample, the change of interplanar distance of (111) plane from 0.331 to 0.327 nm is also observed, confirming that the Pb cations are leached out from CeO2 structure.