Comprehensive evolved gas analysis (EGA) of amorphous precursors for S-doped titania by in situ TG-FTIR and TG/DTA-MS in air: Part 2. Precursor from thiourea and titanium(IV)-n-butoxide

J. Madarász, Ana Brǎileanu, Maria Crişan, G. Pokol

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24 Citations (Scopus)

Abstract

Thermal decomposition of an amorphous precursor for sulfur-doped titania (S:TiO2) nanopowders, prepared by controlled sol-gel hydrolysis-condensation of titanium(IV) tetrabutoxide and thiourea in aqueous butanol, has been studied in situ up to 850 °C in flowing air by simultaneous thermogravimetric and differential thermal analysis coupled online with quadrupole mass spectrometer (TG/DTA-MS) and FTIR spectrometric gas cell (TG-FTIR) for analysis of gases and their evolution dynamics in order to explore and simulate thermal annealing processes of fabrication techniques aimed S:TiO2 photocatalysts with photocatalytic activities under visible light. The studied S-doped precursor's decomposition course remembers to that of non-doped xerogel from Ti(IV)-n-butoxide, which seems to retard a considerable amount of organics in the solid phase even at high temperature, probably in polymeric forms, proven by evolution of CO2 in several temperature regions of decomposition stages. The incorporation form of thiourea in the original xerogel seems to be chemically bounded, resulting lower decomposition temperature than that of pure thiourea, and producing evolution of carbonyl sulfide (COS) already between 120 and 190 °C. Nevertheless, evolution of SO2, and that of CO2 is also observed above 500 °C by both EGA detection methods. The latter observation implies that the blackish grey samples obtained even at 750 °C might be simultaneously S- and C-doped ones.

Original languageEnglish
Pages (from-to)549-556
Number of pages8
JournalJournal of Analytical and Applied Pyrolysis
Volume85
Issue number1-2
DOIs
Publication statusPublished - May 2009

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Thiourea
Gas fuel analysis
Thioureas
Titanium
Differential thermal analysis
Xerogels
Decomposition
Air
Gases
Butanols
Mass spectrometers
Photocatalysts
Butenes
Sulfur
Temperature
Sol-gels
Condensation
Hydrolysis
Pyrolysis
Annealing

Keywords

  • Anatase
  • Evolved gas analysis (EGA)
  • FTIR-spectroscopic gas cell
  • Mass spectrometry (MS)
  • Simultaneous thermogravimetry (TG) and differential thermal analysis (DTA)
  • Thiourea
  • Titania precursor
  • Titanium(IV)-n-butoxide

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Chemistry(all)

Cite this

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title = "Comprehensive evolved gas analysis (EGA) of amorphous precursors for S-doped titania by in situ TG-FTIR and TG/DTA-MS in air: Part 2. Precursor from thiourea and titanium(IV)-n-butoxide",
abstract = "Thermal decomposition of an amorphous precursor for sulfur-doped titania (S:TiO2) nanopowders, prepared by controlled sol-gel hydrolysis-condensation of titanium(IV) tetrabutoxide and thiourea in aqueous butanol, has been studied in situ up to 850 °C in flowing air by simultaneous thermogravimetric and differential thermal analysis coupled online with quadrupole mass spectrometer (TG/DTA-MS) and FTIR spectrometric gas cell (TG-FTIR) for analysis of gases and their evolution dynamics in order to explore and simulate thermal annealing processes of fabrication techniques aimed S:TiO2 photocatalysts with photocatalytic activities under visible light. The studied S-doped precursor's decomposition course remembers to that of non-doped xerogel from Ti(IV)-n-butoxide, which seems to retard a considerable amount of organics in the solid phase even at high temperature, probably in polymeric forms, proven by evolution of CO2 in several temperature regions of decomposition stages. The incorporation form of thiourea in the original xerogel seems to be chemically bounded, resulting lower decomposition temperature than that of pure thiourea, and producing evolution of carbonyl sulfide (COS) already between 120 and 190 °C. Nevertheless, evolution of SO2, and that of CO2 is also observed above 500 °C by both EGA detection methods. The latter observation implies that the blackish grey samples obtained even at 750 °C might be simultaneously S- and C-doped ones.",
keywords = "Anatase, Evolved gas analysis (EGA), FTIR-spectroscopic gas cell, Mass spectrometry (MS), Simultaneous thermogravimetry (TG) and differential thermal analysis (DTA), Thiourea, Titania precursor, Titanium(IV)-n-butoxide",
author = "J. Madar{\'a}sz and Ana Brǎileanu and Maria Crişan and G. Pokol",
year = "2009",
month = "5",
doi = "10.1016/j.jaap.2008.10.017",
language = "English",
volume = "85",
pages = "549--556",
journal = "Journal of Analytical and Applied Pyrolysis",
issn = "0165-2370",
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TY - JOUR

T1 - Comprehensive evolved gas analysis (EGA) of amorphous precursors for S-doped titania by in situ TG-FTIR and TG/DTA-MS in air

T2 - Part 2. Precursor from thiourea and titanium(IV)-n-butoxide

AU - Madarász, J.

AU - Brǎileanu, Ana

AU - Crişan, Maria

AU - Pokol, G.

PY - 2009/5

Y1 - 2009/5

N2 - Thermal decomposition of an amorphous precursor for sulfur-doped titania (S:TiO2) nanopowders, prepared by controlled sol-gel hydrolysis-condensation of titanium(IV) tetrabutoxide and thiourea in aqueous butanol, has been studied in situ up to 850 °C in flowing air by simultaneous thermogravimetric and differential thermal analysis coupled online with quadrupole mass spectrometer (TG/DTA-MS) and FTIR spectrometric gas cell (TG-FTIR) for analysis of gases and their evolution dynamics in order to explore and simulate thermal annealing processes of fabrication techniques aimed S:TiO2 photocatalysts with photocatalytic activities under visible light. The studied S-doped precursor's decomposition course remembers to that of non-doped xerogel from Ti(IV)-n-butoxide, which seems to retard a considerable amount of organics in the solid phase even at high temperature, probably in polymeric forms, proven by evolution of CO2 in several temperature regions of decomposition stages. The incorporation form of thiourea in the original xerogel seems to be chemically bounded, resulting lower decomposition temperature than that of pure thiourea, and producing evolution of carbonyl sulfide (COS) already between 120 and 190 °C. Nevertheless, evolution of SO2, and that of CO2 is also observed above 500 °C by both EGA detection methods. The latter observation implies that the blackish grey samples obtained even at 750 °C might be simultaneously S- and C-doped ones.

AB - Thermal decomposition of an amorphous precursor for sulfur-doped titania (S:TiO2) nanopowders, prepared by controlled sol-gel hydrolysis-condensation of titanium(IV) tetrabutoxide and thiourea in aqueous butanol, has been studied in situ up to 850 °C in flowing air by simultaneous thermogravimetric and differential thermal analysis coupled online with quadrupole mass spectrometer (TG/DTA-MS) and FTIR spectrometric gas cell (TG-FTIR) for analysis of gases and their evolution dynamics in order to explore and simulate thermal annealing processes of fabrication techniques aimed S:TiO2 photocatalysts with photocatalytic activities under visible light. The studied S-doped precursor's decomposition course remembers to that of non-doped xerogel from Ti(IV)-n-butoxide, which seems to retard a considerable amount of organics in the solid phase even at high temperature, probably in polymeric forms, proven by evolution of CO2 in several temperature regions of decomposition stages. The incorporation form of thiourea in the original xerogel seems to be chemically bounded, resulting lower decomposition temperature than that of pure thiourea, and producing evolution of carbonyl sulfide (COS) already between 120 and 190 °C. Nevertheless, evolution of SO2, and that of CO2 is also observed above 500 °C by both EGA detection methods. The latter observation implies that the blackish grey samples obtained even at 750 °C might be simultaneously S- and C-doped ones.

KW - Anatase

KW - Evolved gas analysis (EGA)

KW - FTIR-spectroscopic gas cell

KW - Mass spectrometry (MS)

KW - Simultaneous thermogravimetry (TG) and differential thermal analysis (DTA)

KW - Thiourea

KW - Titania precursor

KW - Titanium(IV)-n-butoxide

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U2 - 10.1016/j.jaap.2008.10.017

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M3 - Article

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VL - 85

SP - 549

EP - 556

JO - Journal of Analytical and Applied Pyrolysis

JF - Journal of Analytical and Applied Pyrolysis

SN - 0165-2370

IS - 1-2

ER -