TY - JOUR
T1 - Improved high-temperature stability and sun-light-driven photocatalytic activity of sulfur-doped anatase TiO2
AU - Periyat, Pradeepan
AU - Pillai, Suresh C.
AU - McCormack, Declan E.
AU - Colreavy, John
AU - Hinder, Steven J.
PY - 2008/5/22
Y1 - 2008/5/22
N2 - Of the various forms of titania (anatase, rutile, and brookite), anatase is reported to be the best photocatalyst. The anatase-to-rutile transformation in pure synthetic titania usually occurs at a temperature range of 600-700 °C. High-temperature (≥800°C) stable anatase titania photocatalyst is required for antibacterial applications in building materials. A simple methodology to extend the anatase phase stability by modifying the titanium isopropoxide precursor with sulfur modification using sulfuric acid is presented. Various TTIP/H2SO4 molar ratios such as 1:1, 1:2, 1:4, 1:8, and 1:16 were prepared, and these samples were characterized by XRD, DSC, Raman spectroscopy, XPS, and BET surface area analysis. Sulfur-modified samples showed extended anatase phase stability up to 900°C, while the control sample prepared under similar conditions completely converted to rutile at 800°C. Stoichiometric modification up to 1:4 TTIP/H 2SO4 composition (TS4) was found to be most effective in extending the anatase-to-rutile phase transformation by 200°C compared to that of the control sample and showed 100% anatase at 800°C and 20% anatase at 900°C. The TS4 composition calcined at various temperatures such as 700, 800, 850 and 900°C showed significantly higher photocatalytic activity compared to the control sample. The TS4 composition calcined at 850°C showed visible light (sunlight) photocatalytic activity, and it decolorized the rhodamine 6G dye within 35 min (rate constant, 0.069 min-1), whereas the control sample prepared under identical conditions decolorized the dye only after 3.5 h (rate constant, 0.007 min-1). It was also observed that the optimal size for the highest photocatalytically active anatase crystal is ∼15 nm. XPS studies indicated that the retention of the anatase phase at high temperatures is due to the existence of small amounts of sulfur up to 900°C.
AB - Of the various forms of titania (anatase, rutile, and brookite), anatase is reported to be the best photocatalyst. The anatase-to-rutile transformation in pure synthetic titania usually occurs at a temperature range of 600-700 °C. High-temperature (≥800°C) stable anatase titania photocatalyst is required for antibacterial applications in building materials. A simple methodology to extend the anatase phase stability by modifying the titanium isopropoxide precursor with sulfur modification using sulfuric acid is presented. Various TTIP/H2SO4 molar ratios such as 1:1, 1:2, 1:4, 1:8, and 1:16 were prepared, and these samples were characterized by XRD, DSC, Raman spectroscopy, XPS, and BET surface area analysis. Sulfur-modified samples showed extended anatase phase stability up to 900°C, while the control sample prepared under similar conditions completely converted to rutile at 800°C. Stoichiometric modification up to 1:4 TTIP/H 2SO4 composition (TS4) was found to be most effective in extending the anatase-to-rutile phase transformation by 200°C compared to that of the control sample and showed 100% anatase at 800°C and 20% anatase at 900°C. The TS4 composition calcined at various temperatures such as 700, 800, 850 and 900°C showed significantly higher photocatalytic activity compared to the control sample. The TS4 composition calcined at 850°C showed visible light (sunlight) photocatalytic activity, and it decolorized the rhodamine 6G dye within 35 min (rate constant, 0.069 min-1), whereas the control sample prepared under identical conditions decolorized the dye only after 3.5 h (rate constant, 0.007 min-1). It was also observed that the optimal size for the highest photocatalytically active anatase crystal is ∼15 nm. XPS studies indicated that the retention of the anatase phase at high temperatures is due to the existence of small amounts of sulfur up to 900°C.
UR - http://www.scopus.com/inward/record.url?scp=53349128360&partnerID=8YFLogxK
U2 - 10.1021/jp0774847
DO - 10.1021/jp0774847
M3 - Article
AN - SCOPUS:53349128360
SN - 1932-7447
VL - 112
SP - 7644
EP - 7652
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 20
ER -