Synthesis of La3+ doped nanocrystalline ceria powder by urea–formaldehyde gel combustion route

Nanocrystalline ceria powders doped with various concentrations of lanthanum oxide have been prepared following gel combustion route using for the first time urea–formaldehyde as fuel. The synthesized products were characterized by XRD, FESEM, TEM, PL and UV–vis spectroscopy. Peak positions of XRD were refined and the lattice parameters were obtained by applying Cohenʹs method. Unit cell parameter increases with concentration of La3+ ion and the variation is consistently linear. XRD calculations showed the dependence of crystallite size on dopant concentrations at lower level. TEM observation revealed unagglomerated particles to be single crystals in the average range of 20–30 nm. Band gap of the La3+ doped ceria materials does not change with doping. Spectroscopic experiments proved the existence of Ce3+ in the formed powder.