Details
| Original language | English |
|---|---|
| Pages (from-to) | 70536-70545 |
| Number of pages | 10 |
| Journal | RSC Advances |
| Volume | 5 |
| Issue number | 86 |
| Publication status | Published - 11 Aug 2015 |
Abstract
The sol-gel technique followed by conventional (TiO 2-1) and hydrothermal (TiO 2-2) thermal treatment was employed to prepare TiO 2-based photocatalysts with distinct particle sizes and crystalline structures. The as prepared metal oxides were evaluated as photocatalysts for gaseous HCHO degradation, methanol, and dye oxidation reactions. Additionally, metallic platinum was deposited on the TiO 2 surfaces and H 2 evolution measurements were performed. The photocatalytic activities were rationalized in terms of morphologic parameters along with the electron/hole dynamics obtained from transient absorption spectroscopy (TAS). TiO 2-2 exhibits smaller particle size, poorer crystallinity, and higher surface area than TiO 2-1. Moreover the hydrothermal treatment leads to formation of the metastable brookite phase, while TiO 2-1 exhibits only the anatase phase. TAS measurements show that the electron/hole recombination of TiO 2-2 is faster than that of the latter. Despite that, TiO 2-2 exhibits higher photonic efficiencies for photocatalytic oxidation reactions, which is attributed to its larger surface area that compensates for the decrease of the surface charge carrier concentration. For H 2 evolution, it was found that the surface area has only a minor effect and the photocatalyst performance is controlled by the efficiency of the electron transfer to the platinum islands. This process is facilitated by the higher crystallinity of TiO 2-1, which exhibits higher photonic efficiency for H 2 evolution than that observed for TiO 2-2. The results found here provide new insights into the correlations between thermal treatment conditions and photocatalytic activity and will be useful for the design of high performance photocatalysts.
ASJC Scopus subject areas
- Chemistry(all)
- General Chemistry
- Chemical Engineering(all)
- General Chemical Engineering
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In: RSC Advances, Vol. 5, No. 86, 11.08.2015, p. 70536-70545.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Charge carrier dynamics and photocatalytic behavior of TiO2 nanopowders submitted to hydrothermal or conventional heat treatment
AU - Patrocinio, A.O.T.
AU - Schneider, J.
AU - França, M.D.
AU - Santos, L.M.
AU - Caixeta, B.P.
AU - Machado, A.E.H.
AU - Bahnemann, D.W.
N1 - Publisher Copyright: © The Royal Society of Chemistry 2015. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2015/8/11
Y1 - 2015/8/11
N2 - The sol-gel technique followed by conventional (TiO 2-1) and hydrothermal (TiO 2-2) thermal treatment was employed to prepare TiO 2-based photocatalysts with distinct particle sizes and crystalline structures. The as prepared metal oxides were evaluated as photocatalysts for gaseous HCHO degradation, methanol, and dye oxidation reactions. Additionally, metallic platinum was deposited on the TiO 2 surfaces and H 2 evolution measurements were performed. The photocatalytic activities were rationalized in terms of morphologic parameters along with the electron/hole dynamics obtained from transient absorption spectroscopy (TAS). TiO 2-2 exhibits smaller particle size, poorer crystallinity, and higher surface area than TiO 2-1. Moreover the hydrothermal treatment leads to formation of the metastable brookite phase, while TiO 2-1 exhibits only the anatase phase. TAS measurements show that the electron/hole recombination of TiO 2-2 is faster than that of the latter. Despite that, TiO 2-2 exhibits higher photonic efficiencies for photocatalytic oxidation reactions, which is attributed to its larger surface area that compensates for the decrease of the surface charge carrier concentration. For H 2 evolution, it was found that the surface area has only a minor effect and the photocatalyst performance is controlled by the efficiency of the electron transfer to the platinum islands. This process is facilitated by the higher crystallinity of TiO 2-1, which exhibits higher photonic efficiency for H 2 evolution than that observed for TiO 2-2. The results found here provide new insights into the correlations between thermal treatment conditions and photocatalytic activity and will be useful for the design of high performance photocatalysts.
AB - The sol-gel technique followed by conventional (TiO 2-1) and hydrothermal (TiO 2-2) thermal treatment was employed to prepare TiO 2-based photocatalysts with distinct particle sizes and crystalline structures. The as prepared metal oxides were evaluated as photocatalysts for gaseous HCHO degradation, methanol, and dye oxidation reactions. Additionally, metallic platinum was deposited on the TiO 2 surfaces and H 2 evolution measurements were performed. The photocatalytic activities were rationalized in terms of morphologic parameters along with the electron/hole dynamics obtained from transient absorption spectroscopy (TAS). TiO 2-2 exhibits smaller particle size, poorer crystallinity, and higher surface area than TiO 2-1. Moreover the hydrothermal treatment leads to formation of the metastable brookite phase, while TiO 2-1 exhibits only the anatase phase. TAS measurements show that the electron/hole recombination of TiO 2-2 is faster than that of the latter. Despite that, TiO 2-2 exhibits higher photonic efficiencies for photocatalytic oxidation reactions, which is attributed to its larger surface area that compensates for the decrease of the surface charge carrier concentration. For H 2 evolution, it was found that the surface area has only a minor effect and the photocatalyst performance is controlled by the efficiency of the electron transfer to the platinum islands. This process is facilitated by the higher crystallinity of TiO 2-1, which exhibits higher photonic efficiency for H 2 evolution than that observed for TiO 2-2. The results found here provide new insights into the correlations between thermal treatment conditions and photocatalytic activity and will be useful for the design of high performance photocatalysts.
UR - http://www.scopus.com/inward/record.url?scp=84940403653&partnerID=8YFLogxK
U2 - 10.1039/c5ra13291f
DO - 10.1039/c5ra13291f
M3 - Article
VL - 5
SP - 70536
EP - 70545
JO - RSC Advances
JF - RSC Advances
SN - 2046-2069
IS - 86
ER -