Abstract
In this paper we report on the photocatalytic behavior in gas phase
propane oxidation of well-defined TiO2 nanoparticle (NP) coatings
prepared via Supersonic Cluster Beam Deposition (SCBD) on Si-wafers and
quartz substrates. The temperature dependent crystal phase of the
coatings was analyzed by Raman spectroscopy, and the morphology by High
Resolution-Scanning Electron Microscopy.
SCBD deposition in the presence of oxygen enables the in situ synthesis
of TiO2 layers of amorphous NP at room temperature. Adapting the
deposition temperature to 500 degrees C or 650 degrees C leads to
Anatase crystals of variable size ranges, and layers showing significant
porosity. At 800 degrees C mainly Rutile is formed. Post annealing by
wafer heating of the amorphous NP prepared at room temperature results
in comparable temperature dependent phases and morphologies.
Photocatalytic activity in propane oxidation was dependent on the
morphology of the samples: the activity decreases as a function of
increasing particle size. The presence of water vapor in the propane
feed generally increased the activity of the wafer-heated samples,
suggesting OH groups are not profoundly present on SCBD synthesized
layers. In addition, a remarkable effect of the substrate (Si or Quartz)
was observed: strong interaction between Si and TiO2 is largely
detrimental for photocatalytic activity.
The consequences of these findings for the application of SCBD to
synthesize samples for fundamental (spectroscopic) study of
photocatalysis are discussed. (C) 2013 Elsevier B.V. All rights
reserved.
Lingua originale | English |
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pagine (da-a) | S467-S471 |
Numero di pagine | 5 |
Rivista | Journal of Alloys and Compounds |
Volume | 615 |
DOI | |
Stato di pubblicazione | Pubblicato - 2014 |
Keywords
- Catalysis
- Nanostructured materials
- Surfaces and interfaces
- Titanium dioxide