Details
| Original language | English |
|---|---|
| Pages (from-to) | 142-151 |
| Number of pages | 10 |
| Journal | Journal of Photochemistry and Photobiology A: Chemistry |
| Volume | 366 |
| Early online date | 3 Feb 2018 |
| Publication status | Published - 1 Nov 2018 |
Abstract
Building materials employing TiO 2 as photocatalyst usually contain several additives. The interplay of the additives and the photocatalytic NO degradation has been rarely investigated, although it is of utmost importance for the design of new highly active materials. Hence, in the present study the effects of such additives (BaSO 4, CaCO 3, and Na 2CO 3) on the photocatalytic activity and on the charge carrier dynamics have been evaluated. The degradation of nitric oxide (NO) was studied employing a standardized photocatalytic activity test (ISO 22197-1) and the charge carrier kinetics were observed by transient absorption spectroscopy. TiO 2-additive powder samples were obtained by grinding pure anatase TiO 2 with a single additive with varying volume composition. Overall, the obtained apparent quantum yields of the samples correlated well with the charge carrier concentration. Moreover, BaSO 4 has proven its chemically inert character. However, the optical properties of the powder samples containing BaSO 4 lead to relatively high photonic efficiencies even with low TiO 2 content. TiO 2-BaSO 4 samples with only 25% TiO 2 showed nearly the same quantum yield for the NO degradation as the pure photocatalyst. The reason for the high photocatalytic activity is the strong absorption of UV-light caused by the scattering inside the powder samples. The charge carrier kinetics of TiO 2 after the addition of Na 2CO 3 and CaCO 3 revealed two different chemical effects of the additives. Na 2CO 3 reduced the apparent quantum yield of the TiO 2 samples due to the fast recombination of charge carriers (identified by a fractal kinetics fit). On the other hand, the presence of CaCO 3 had a beneficial influence on the stabilization of trapped charge carriers in TiO 2.
Keywords
- Barium sulfate, Carbonate, Charge carrier dynamics, Kinetics, Nitric oxide degradation, Photocatalysis, Semiconductor, Transient absorption spectroscopy
ASJC Scopus subject areas
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In: Journal of Photochemistry and Photobiology A: Chemistry, Vol. 366, 01.11.2018, p. 142-151.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Influence of inorganic additives on the photocatalytic removal of nitric oxide and on the charge carrier dynamics of TiO2 powders
AU - Sieland, F.
AU - Duong, N.A.-T.
AU - Schneider, J.
AU - Bahnemann, D.W.
N1 - Funding information: We would like to thank Dr. Dillert, Prof. Patrocinio and Dr. Dorfs for helpful discussion. F. Sieland acknowledges support from the Foundation of German Business (sdw). Furthermore, financial support from the Federal Ministry of Education and Research (BMBF) Project “PureBau” No. 13N13350 and supply of TiO 2 materials from KRONOS International, Inc. is acknowledged.
PY - 2018/11/1
Y1 - 2018/11/1
N2 - Building materials employing TiO 2 as photocatalyst usually contain several additives. The interplay of the additives and the photocatalytic NO degradation has been rarely investigated, although it is of utmost importance for the design of new highly active materials. Hence, in the present study the effects of such additives (BaSO 4, CaCO 3, and Na 2CO 3) on the photocatalytic activity and on the charge carrier dynamics have been evaluated. The degradation of nitric oxide (NO) was studied employing a standardized photocatalytic activity test (ISO 22197-1) and the charge carrier kinetics were observed by transient absorption spectroscopy. TiO 2-additive powder samples were obtained by grinding pure anatase TiO 2 with a single additive with varying volume composition. Overall, the obtained apparent quantum yields of the samples correlated well with the charge carrier concentration. Moreover, BaSO 4 has proven its chemically inert character. However, the optical properties of the powder samples containing BaSO 4 lead to relatively high photonic efficiencies even with low TiO 2 content. TiO 2-BaSO 4 samples with only 25% TiO 2 showed nearly the same quantum yield for the NO degradation as the pure photocatalyst. The reason for the high photocatalytic activity is the strong absorption of UV-light caused by the scattering inside the powder samples. The charge carrier kinetics of TiO 2 after the addition of Na 2CO 3 and CaCO 3 revealed two different chemical effects of the additives. Na 2CO 3 reduced the apparent quantum yield of the TiO 2 samples due to the fast recombination of charge carriers (identified by a fractal kinetics fit). On the other hand, the presence of CaCO 3 had a beneficial influence on the stabilization of trapped charge carriers in TiO 2.
AB - Building materials employing TiO 2 as photocatalyst usually contain several additives. The interplay of the additives and the photocatalytic NO degradation has been rarely investigated, although it is of utmost importance for the design of new highly active materials. Hence, in the present study the effects of such additives (BaSO 4, CaCO 3, and Na 2CO 3) on the photocatalytic activity and on the charge carrier dynamics have been evaluated. The degradation of nitric oxide (NO) was studied employing a standardized photocatalytic activity test (ISO 22197-1) and the charge carrier kinetics were observed by transient absorption spectroscopy. TiO 2-additive powder samples were obtained by grinding pure anatase TiO 2 with a single additive with varying volume composition. Overall, the obtained apparent quantum yields of the samples correlated well with the charge carrier concentration. Moreover, BaSO 4 has proven its chemically inert character. However, the optical properties of the powder samples containing BaSO 4 lead to relatively high photonic efficiencies even with low TiO 2 content. TiO 2-BaSO 4 samples with only 25% TiO 2 showed nearly the same quantum yield for the NO degradation as the pure photocatalyst. The reason for the high photocatalytic activity is the strong absorption of UV-light caused by the scattering inside the powder samples. The charge carrier kinetics of TiO 2 after the addition of Na 2CO 3 and CaCO 3 revealed two different chemical effects of the additives. Na 2CO 3 reduced the apparent quantum yield of the TiO 2 samples due to the fast recombination of charge carriers (identified by a fractal kinetics fit). On the other hand, the presence of CaCO 3 had a beneficial influence on the stabilization of trapped charge carriers in TiO 2.
KW - Barium sulfate
KW - Carbonate
KW - Charge carrier dynamics
KW - Kinetics
KW - Nitric oxide degradation
KW - Photocatalysis
KW - Semiconductor
KW - Transient absorption spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=85042183316&partnerID=8YFLogxK
U2 - 10.1016/j.jphotochem.2018.01.036
DO - 10.1016/j.jphotochem.2018.01.036
M3 - Article
VL - 366
SP - 142
EP - 151
JO - Journal of Photochemistry and Photobiology A: Chemistry
JF - Journal of Photochemistry and Photobiology A: Chemistry
SN - 1010-6030
ER -