Control of Particle Morphology and Size in Vapor-Phase Synthesis of Titania, Silica and Alumina Nanoparticles †

Previous studies on vapor-phase synthesis of titania (TiO2), silica (SiO2), and alumina (Al2O3) nanoparticles were reviewed. Interactions between physicochemical phenomena involved in the particle growth and the operating variables were investigated. Strategies to produce non-aggregated spherical particles of the metal oxides are discussed. Model predictions based on the sintering laws without any adjustments in the sintering parameters rarely agreed with experimental data. There remains more to be understood in reaction and nucleation kinetics, sintering, and fragmentation mechanisms until the technology is developed to the stage of designing reactors for mass production of non-aggregated spherical particles for titania, silica and alumina