Details
| Original language | English |
|---|---|
| Article number | 112112 |
| Journal | Journal of Photochemistry and Photobiology A: Chemistry |
| Volume | 386 |
| Early online date | 26 Sept 2019 |
| Publication status | Published - 1 Jan 2020 |
Abstract
In this work, transient absorption spectroscopy studies in the microsecond time scale were carried out to investigate the dynamics of photogenerated electron-hole pairs in TiO 2-rGO nanocomposites, prepared by a hydrothermal method, under different atmospheres: N 2, O 2, and N 2 saturated in CH 3OH. Under N 2 atmosphere, the transient absorption signal detected in the region between 450 and 700 nm dropped as the rGO mass concentration in the composite was raised. The electron transfer from TiO 2 to rGO was confirmed by using a model based on fractal surfaces which describes the decay kinetics. In the presence of methanol as hole acceptor, P25-rGO 0.5% and 1% were able to reach the maximum transient absorption faster than the other studied nanocomposites. However, after 10 μs, the P25-rGO 0.1% nanocomposite yielded the highest transient absorption signal and the best conversion and initial reaction rate in the photocatalytic degradation of dichloroacetic acid in aqueous suspensions. The effect of rGO on free electrons was investigated by detecting the transient signal at 980 nm under N 2 saturated in CH 3OH, for the different samples. It was found that the measured signals followed the same response than at 660 nm further evincing the electron transfer process. No sensitization effect of rGO was observed when the samples were excited at 450 nm.
Keywords
- Charge carrier dynamics, Fractal kinetic model, Reduced graphene oxide, TiO -rGO, Transient absorption spectroscopy
ASJC Scopus subject areas
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In: Journal of Photochemistry and Photobiology A: Chemistry, Vol. 386, 112112, 01.01.2020.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - TiO2-reduced graphene oxide nanocomposites
T2 - Microsecond charge carrier kinetics
AU - Tolosana-Moranchel, A.
AU - Faraldos, M.
AU - Bahamonde, A.
AU - Pascual, L.
AU - Sieland, F.
AU - Schneider, J.
AU - Dillert, R.
AU - Bahnemann, D.W.
N1 - Funding Information: This work has been supported by the Spanish Plan Nacional de I+D+i through the project CTM2015-64895-R. Alvaro Tolosana-Moranchel thanks to Ministerio de Educación, Cultura y Deporte for his FPU grant ( FPU14/01605 ) and ( EST16/00065 ). The authors are also grateful to Technical Research Support Unit of Instituto de Catálisis y Petroleoquímica (CSIC).
PY - 2020/1/1
Y1 - 2020/1/1
N2 - In this work, transient absorption spectroscopy studies in the microsecond time scale were carried out to investigate the dynamics of photogenerated electron-hole pairs in TiO 2-rGO nanocomposites, prepared by a hydrothermal method, under different atmospheres: N 2, O 2, and N 2 saturated in CH 3OH. Under N 2 atmosphere, the transient absorption signal detected in the region between 450 and 700 nm dropped as the rGO mass concentration in the composite was raised. The electron transfer from TiO 2 to rGO was confirmed by using a model based on fractal surfaces which describes the decay kinetics. In the presence of methanol as hole acceptor, P25-rGO 0.5% and 1% were able to reach the maximum transient absorption faster than the other studied nanocomposites. However, after 10 μs, the P25-rGO 0.1% nanocomposite yielded the highest transient absorption signal and the best conversion and initial reaction rate in the photocatalytic degradation of dichloroacetic acid in aqueous suspensions. The effect of rGO on free electrons was investigated by detecting the transient signal at 980 nm under N 2 saturated in CH 3OH, for the different samples. It was found that the measured signals followed the same response than at 660 nm further evincing the electron transfer process. No sensitization effect of rGO was observed when the samples were excited at 450 nm.
AB - In this work, transient absorption spectroscopy studies in the microsecond time scale were carried out to investigate the dynamics of photogenerated electron-hole pairs in TiO 2-rGO nanocomposites, prepared by a hydrothermal method, under different atmospheres: N 2, O 2, and N 2 saturated in CH 3OH. Under N 2 atmosphere, the transient absorption signal detected in the region between 450 and 700 nm dropped as the rGO mass concentration in the composite was raised. The electron transfer from TiO 2 to rGO was confirmed by using a model based on fractal surfaces which describes the decay kinetics. In the presence of methanol as hole acceptor, P25-rGO 0.5% and 1% were able to reach the maximum transient absorption faster than the other studied nanocomposites. However, after 10 μs, the P25-rGO 0.1% nanocomposite yielded the highest transient absorption signal and the best conversion and initial reaction rate in the photocatalytic degradation of dichloroacetic acid in aqueous suspensions. The effect of rGO on free electrons was investigated by detecting the transient signal at 980 nm under N 2 saturated in CH 3OH, for the different samples. It was found that the measured signals followed the same response than at 660 nm further evincing the electron transfer process. No sensitization effect of rGO was observed when the samples were excited at 450 nm.
KW - Charge carrier dynamics
KW - Fractal kinetic model
KW - Reduced graphene oxide
KW - TiO -rGO
KW - Transient absorption spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=85073011549&partnerID=8YFLogxK
U2 - 10.1016/j.jphotochem.2019.112112
DO - 10.1016/j.jphotochem.2019.112112
M3 - Article
VL - 386
JO - Journal of Photochemistry and Photobiology A: Chemistry
JF - Journal of Photochemistry and Photobiology A: Chemistry
SN - 1010-6030
M1 - 112112
ER -