Investigation of ultrafine titanium dioxide aerosol size and structure during anatase-to-rutile transformation

Petri Ahonen, Anna Moisala, Olivier Richard, David Brown, Jorma Jokiniemi, Unto Tapper, Esko Kauppinen, Jean-Claude Joubert, Jean Deschanvres

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific


    We have studied the ultrafine TiO2 particle morphology and phase transformation from anatase to rutile in aerosol reactor. The particles were prepared via aerosol decomposition of titanium tetraisopropoxide (TTIP) droplets. Aerosol was produced by dispersing precursor solution by aerosol nebulizer and subsequently evaporating the propanol solvent. The TTIP droplets were size selected using a differential mobility analyzer (DMA). The 45 nm mobility size fraction was transported to a tube reactor in air carrier gas with a flow rate of 1.0 lpm. Experimental runs were made between 600 and 900 °C. In the flow reactor the TTIP droplets were thermolyzed to TiO2 particles. The particle size was measured with a second DMA downstream of the flow reactor. Particle microstructure was investigated with transmission electron microscope (TEM). Computer simulations of the reactor temperature and flow fields were made. The tandem-DMA results show how particle size is reduced during the aerosol decomposition and subsequently by TiO2 densification and phase change. The original TTIP droplet size is reduced by 30 % at 700 °C reactor temperature and finally by 35 % at 900 °C to reach 30 nm rutile particle size. The high resolution TEM (HR-TEM) and electron diffraction (ED) results of the nanosized TiO2 particles reveal the crystallite size and phase transformation at different reactor temperatures.
    Original languageEnglish
    Title of host publicationAIChE 2000 annual meeting
    PublisherAmerican Institute of Chemical Engineers (AIChE)
    Publication statusPublished - 2000
    MoE publication typeB3 Non-refereed article in conference proceedings
    Event2000 AIChE Annual Meeting - Los Angeles, United States
    Duration: 12 Nov 200017 Nov 2000


    Conference2000 AIChE Annual Meeting
    Country/TerritoryUnited States
    CityLos Angeles


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