Manganese-doped ceria nanoparticles grain growth kinetics

Grain growth kinetics of nanosized ceria, pure and doped with 10, 20 and 30% of manganese, were investigated. Hydrothermally produced nanoparticles were isothermally annealed at temperatures in a range between 500 and 700 degrees C for different annealing times. The average nanoparticle crystallite sizes were determined using X-ray diffraction data via the Scherrer equation and compared to grain size gained by using transmission electron microscopy. On the basis of obtained data, the kinetics of ceria nanoparticles grain growth was studied using an isothermal and a non-isothermal model. It was shown that the presence of manganese inhibits ceria grain growth by reducing the grain growth rate. Activation energy for ceria grain growth, between 226 and 229 kJ mol(-1) for pure and 114 and 130 kJ mol(-1) for doped samples were obtained. Although doped samples show lesser grain growth activation energies, they also have lesser pre-exponential constant and thus increased thermal stability.