Photocatalysis with Chromium-Doped TiO2: Bulk and Surface Doping

The photocatalytic properties of TiO2 modified by chromium are usually found to depend strongly on the preparation method. To clarify this problem, two series of chromium‐doped titania with a chromium content of up to 1.56 wt % have been prepared under hydrothermal conditions: the first series (Cr:T...

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Bibliographic Details
Published in:ChemSusChem 2014-05, Vol.7 (5), p.1361-1371
Main Authors: Ould-Chikh, Samy, Proux, Olivier, Afanasiev, Pavel, Khrouz, Lhoussain, Hedhili, Mohamed N., Anjum, Dalaver H., Harb, Moussab, Geantet, Christophe, Basset, Jean-Marie, Puzenat, Eric
Format: Article
Language:English
Subjects:
Catalysis
Chromium
Chromium - chemistry
doping
Formates - chemistry
Microprocessors
Microscopy, Electron, Transmission
Oxidation-Reduction
Photocatalysis
Photochemical Processes
photochemistry
Spectrophotometry, Atomic
Spectrum Analysis, Raman
surface chemistry
Surface Properties
titanium
Titanium - chemistry
X-Ray Absorption Spectroscopy
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Summary:The photocatalytic properties of TiO2 modified by chromium are usually found to depend strongly on the preparation method. To clarify this problem, two series of chromium‐doped titania with a chromium content of up to 1.56 wt % have been prepared under hydrothermal conditions: the first series (Cr:TiO2) is intended to dope the bulk of TiO2, whereas the second series (Cr/TiO2) is intended to load the surface of TiO2 with Cr. The catalytic properties have been compared in the photocatalytic oxidation of formic acid. Characterization data provides evidence that in the Cr/TiO2 catalysts chromium is located on the surface of TiO2 as amorphous CrOOH clusters. In contrast, in the Cr:TiO2 series, chromium is mostly dissolved in the titania lattice, although a minor part is still present on the surface. Photocatalytic tests show that both series of chromium‐doped titania demonstrate visible‐light‐driven photo‐oxidation activity. Surface‐doped Cr/TiO2 solids appear to be more efficient photocatalysts than the bulk‐doped Cr:TiO2 counterparts. It's classified! The photocatalytic properties of TiO2 modified by chromium depend strongly on the preparation method. To clarify this problem, two types of modified titania are discussed: one with CrIII doped in the bulk and one with CrOOH clusters on the TiO2 surface (see picture). Both series show visible‐light‐driven photo‐oxidation activity. However, surface modification appears to be a more efficient strategy.
ISSN:1864-5631
1864-564X
DOI:10.1002/cssc.201300922