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A dopant-mediated recombination mechanism in Fe-doped TiO2 nanoparticles for the photocatalytic decomposition of nitric oxide

Paper ID Volume ID Publish Year Pages File Format Full-Text
54291 47004 2014 6 PDF Available
Title
A dopant-mediated recombination mechanism in Fe-doped TiO2 nanoparticles for the photocatalytic decomposition of nitric oxide
Abstract

•Presence of Fe dopant in TiO2 strongly suppresses photo-oxidation of NO to NO2.•Fe3+ is photo-reduced to Fe2+, providing a favorable adsorption site for NO.•Photo-generated hydroxyl radicals re-oxidize Fe and trigger release of NO.•Dopant-mediated recombination can enhance selectivity of photocatalysts.•A new IR band at 1805 cm−1 is observed for Fe:TiO2 and attributed to Fe2+(NO)2.

The photon-assisted adsorption and catalytic decomposition of nitric oxide (NO) over undoped and Fe-doped TiO2 nanoparticles have been investigated by in situ diffuse reflectance infrared Fourier transformed (DRIFT) spectroscopy, in situ X-ray photoelectron spectroscopy (XPS) and on-line NOx analysis. The DRIFT spectra and on-line NOx analysis reveal that the usual photo-oxidation of NO to NO2 is strongly suppressed by the Fe dopant. This is found to be caused by the photo-reduction of Fe3+ to Fe2+, which is an effective adsorption site for nitric oxide species. The DRIFT spectra indeed reveal a new band at 1805 cm−1, which is assigned to the NO stretch vibration in a Fe2+(NO)2 complex. Instead of producing NO2, photo-generated hydroxyl radicals oxidize the Fe2+ back to Fe3+. This causes the NO to desorb again, effectively closing an NO-mediated recombination loop. These results support the recently proposed reaction mechanisms for the photocatalytic decomposition of NO over undoped and Fe-doped TiO2, and provide new insights for the development of highly selective photocatalysts based on doped metal oxides.

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Keywords
Photocatalysis; TiO2; Nanoparticles; Fe-doping; Nitric oxide; IR spectroscopy
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A dopant-mediated recombination mechanism in Fe-doped TiO2 nanoparticles for the photocatalytic decomposition of nitric oxide
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 225, 15 April 2014, Pages 96–101
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us