Formation Studies on the Nonaqueous Synthesis of Metal Oxide Nanoparticles in a 1.5 L Reactor System

In the last years, the nonaqueous synthesis has been demonstrated as a highly versatile method for the simple synthesis of highly crystalline metal oxide nanoparticles and nanomaterials. Thereby, we have presented the synthesis of a multitude of different metal oxides (e.g., TiO2, ZrO2, BaTiO3, Fe3O4). The mechanisms of particle formation as well as the influence of process parameters on the particle properties however remain largely unknown so far, as the molecular mechanisms are rather complex. In this paper, we show that the synthesis of metal oxide nanoparticles is feasible also on a multi-gram reactor scale on the example of anatase TiO2 nanoparticles. Using a reactor system equipped with a sampling system for withdrawal of samples at different stages of the reaction, the kinetics of particle formation could be determined and compared to the formation of organic side products and water. Additionally, insights into the influence of different process parameters on the particle properties are shown and can be utilized to tailor size and morphology of the product nanoparticles.