Nano preparation of Dy3+ substituted ceria via urea-formaldehyde gel combustion route

Nanocrystalline ceria powders have been synthesised via the gel combustion route, using for the first time urea formaldehyde as fuel for doping of dysprosium oxide. This synthesis route can produce well-crystallised powder within a one step combustion process, eliminating the need for further calcinations. The formation sequences have been described through differential scanning calorimetry-thermo gravimetric analysis study and the crystallinity of the powder was examined using X-ray diffraction, selected area electron diffraction and high resolution patterns. Lattice parameter was found to increase with doping concentration. Very fine grains in the size range of 3-5 nm are found to occur in the form of large and soft agglomerates (50-130 nm). The optical band gap suggests that those powders with low dopant concentration may have useful applications in UV-shielding and in transparent conducting film