Synthesis and characterization of metal oxide nanoparticles

TiO2 nanoparticles were prepared from titanium isopropoxide in aqueous solution, and the particle size and size distribution were determined as a function of time and temperature. We also prepared ZnO nanoparticles using precipitation from Zn(Ac)(2), Zn(ClO4)(2) and ZnBr2 in isopropanol. In both cases, nucleation and growth were fast, and coarsening and aggregation were the main factors in determining the particle size and distribution. We show that coarsening of ZnO and TiO2 nanoparticles follows the Lifshitz-Slyozov-Wagner rate law for diffusion controlled coarsening originally derived for colloidal systems with micron size particles, where the average particle size cubed is proportional to time. We show that the dominant parameters controlling the coarsening kinetics are solvent, precursor salt, and temperature.