Aerosol production and crystallization of titanium dioxide from metal alkoxide droplets: Dissertation

Petri Ahonen

Research output: ThesisDissertationCollection of Articles

1 Citation (Scopus)

Abstract

In this experimental study, aerosol methods for producing titanium dioxide powders and increasing our knowledge of particle and crystal formation have been developed. Powders and ultrafine particles of titanium oxide were produced by an aerosol droplet decomposition route in tubular laminar flow reactors in air and nitrogen atmospheres. Reactor temperatures up to 1500°C were used with residence times in the range of 1-50 s. Novel methods were introduced for the production of micron sized powders, investigation of crystallization of anatase in the particles, and for studying the formation of crystal phase and morphology on ultrafine particles at different temperatures. High-resolution transmission electron microscopy, scanning electron microscopy, aerosol measurements by differential mobility analyzer and inertial impactor as well as materials characterization by diffraction and spectroscopic methods were performed. In addition, the production conditions in aerosol reactors were evaluated using computational fluid dynamics calculations. The results showed that titanium dioxide powders can be produced from ultrafine up to micron sized particles via droplet decomposition and in-droplet hydrolysis methods starting from a titanium alkoxide precursor. Crystal phase and crystallite size can be controlled by reactor conditions and by thermal post-annealing. Anatase formation in amorphous particles was observed near surfaces. Investigation of ultrafine particles revealed morphology development of rutile and anatase single crystals. The 60 and 120 nm diameter rutile crystal morphologies development was observed in mobility particle size measurements. The 20 nm diameter anatase particle morphology showed the development of crystallographic {011} and {001} surfaces.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • Aalto University
Supervisors/Advisors
  • Kauppinen, Esko, Supervisor, External person
  • Joubert, Jean-Claude, Supervisor, External person
Award date14 Sep 2001
Place of PublicationEspoo
Publisher
Print ISBNs951-38-5857-X
Electronic ISBNs951-38-5858-8
Publication statusPublished - 2001
MoE publication typeG5 Doctoral dissertation (article)

Fingerprint

alkoxides
titanium oxides
aerosols
crystallization
metals
anatase
reactors
rutile
crystals
decomposition
impactors
crystal morphology
computational fluid dynamics
laminar flow
hydrolysis
analyzers
titanium
routes
nitrogen
atmospheres

Keywords

  • aerosols
  • particles
  • synthesis
  • pyrolysis
  • hydrolysis
  • alkoxides
  • titanium dioxide
  • anatase
  • rutile
  • crystal morphology

Cite this

Ahonen, P. (2001). Aerosol production and crystallization of titanium dioxide from metal alkoxide droplets: Dissertation. Espoo: VTT Technical Research Centre of Finland.
Ahonen, Petri. / Aerosol production and crystallization of titanium dioxide from metal alkoxide droplets : Dissertation. Espoo : VTT Technical Research Centre of Finland, 2001. 59 p.
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title = "Aerosol production and crystallization of titanium dioxide from metal alkoxide droplets: Dissertation",
abstract = "In this experimental study, aerosol methods for producing titanium dioxide powders and increasing our knowledge of particle and crystal formation have been developed. Powders and ultrafine particles of titanium oxide were produced by an aerosol droplet decomposition route in tubular laminar flow reactors in air and nitrogen atmospheres. Reactor temperatures up to 1500°C were used with residence times in the range of 1-50 s. Novel methods were introduced for the production of micron sized powders, investigation of crystallization of anatase in the particles, and for studying the formation of crystal phase and morphology on ultrafine particles at different temperatures. High-resolution transmission electron microscopy, scanning electron microscopy, aerosol measurements by differential mobility analyzer and inertial impactor as well as materials characterization by diffraction and spectroscopic methods were performed. In addition, the production conditions in aerosol reactors were evaluated using computational fluid dynamics calculations. The results showed that titanium dioxide powders can be produced from ultrafine up to micron sized particles via droplet decomposition and in-droplet hydrolysis methods starting from a titanium alkoxide precursor. Crystal phase and crystallite size can be controlled by reactor conditions and by thermal post-annealing. Anatase formation in amorphous particles was observed near surfaces. Investigation of ultrafine particles revealed morphology development of rutile and anatase single crystals. The 60 and 120 nm diameter rutile crystal morphologies development was observed in mobility particle size measurements. The 20 nm diameter anatase particle morphology showed the development of crystallographic {011} and {001} surfaces.",
keywords = "aerosols, particles, synthesis, pyrolysis, hydrolysis, alkoxides, titanium dioxide, anatase, rutile, crystal morphology",
author = "Petri Ahonen",
year = "2001",
language = "English",
isbn = "951-38-5857-X",
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publisher = "VTT Technical Research Centre of Finland",
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Aerosol production and crystallization of titanium dioxide from metal alkoxide droplets : Dissertation. / Ahonen, Petri.

Espoo : VTT Technical Research Centre of Finland, 2001. 59 p.

Research output: ThesisDissertationCollection of Articles

TY - THES

T1 - Aerosol production and crystallization of titanium dioxide from metal alkoxide droplets

T2 - Dissertation

AU - Ahonen, Petri

PY - 2001

Y1 - 2001

N2 - In this experimental study, aerosol methods for producing titanium dioxide powders and increasing our knowledge of particle and crystal formation have been developed. Powders and ultrafine particles of titanium oxide were produced by an aerosol droplet decomposition route in tubular laminar flow reactors in air and nitrogen atmospheres. Reactor temperatures up to 1500°C were used with residence times in the range of 1-50 s. Novel methods were introduced for the production of micron sized powders, investigation of crystallization of anatase in the particles, and for studying the formation of crystal phase and morphology on ultrafine particles at different temperatures. High-resolution transmission electron microscopy, scanning electron microscopy, aerosol measurements by differential mobility analyzer and inertial impactor as well as materials characterization by diffraction and spectroscopic methods were performed. In addition, the production conditions in aerosol reactors were evaluated using computational fluid dynamics calculations. The results showed that titanium dioxide powders can be produced from ultrafine up to micron sized particles via droplet decomposition and in-droplet hydrolysis methods starting from a titanium alkoxide precursor. Crystal phase and crystallite size can be controlled by reactor conditions and by thermal post-annealing. Anatase formation in amorphous particles was observed near surfaces. Investigation of ultrafine particles revealed morphology development of rutile and anatase single crystals. The 60 and 120 nm diameter rutile crystal morphologies development was observed in mobility particle size measurements. The 20 nm diameter anatase particle morphology showed the development of crystallographic {011} and {001} surfaces.

AB - In this experimental study, aerosol methods for producing titanium dioxide powders and increasing our knowledge of particle and crystal formation have been developed. Powders and ultrafine particles of titanium oxide were produced by an aerosol droplet decomposition route in tubular laminar flow reactors in air and nitrogen atmospheres. Reactor temperatures up to 1500°C were used with residence times in the range of 1-50 s. Novel methods were introduced for the production of micron sized powders, investigation of crystallization of anatase in the particles, and for studying the formation of crystal phase and morphology on ultrafine particles at different temperatures. High-resolution transmission electron microscopy, scanning electron microscopy, aerosol measurements by differential mobility analyzer and inertial impactor as well as materials characterization by diffraction and spectroscopic methods were performed. In addition, the production conditions in aerosol reactors were evaluated using computational fluid dynamics calculations. The results showed that titanium dioxide powders can be produced from ultrafine up to micron sized particles via droplet decomposition and in-droplet hydrolysis methods starting from a titanium alkoxide precursor. Crystal phase and crystallite size can be controlled by reactor conditions and by thermal post-annealing. Anatase formation in amorphous particles was observed near surfaces. Investigation of ultrafine particles revealed morphology development of rutile and anatase single crystals. The 60 and 120 nm diameter rutile crystal morphologies development was observed in mobility particle size measurements. The 20 nm diameter anatase particle morphology showed the development of crystallographic {011} and {001} surfaces.

KW - aerosols

KW - particles

KW - synthesis

KW - pyrolysis

KW - hydrolysis

KW - alkoxides

KW - titanium dioxide

KW - anatase

KW - rutile

KW - crystal morphology

M3 - Dissertation

SN - 951-38-5857-X

T3 - VTT Publications

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Ahonen P. Aerosol production and crystallization of titanium dioxide from metal alkoxide droplets: Dissertation. Espoo: VTT Technical Research Centre of Finland, 2001. 59 p.