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RSC Advances
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DOI: 10.1039/C5RA19151C
ARTICLE
Journal Name
other three catalysts, Pt-1.0FeOx/Al2O3 catalyst exhibits the highest oxidation of formaldehyde. A variety of characterization results
catalytic activity. This might be indicative that more interacting Pt- revealed that the Pt nanoparticles and iron oxides are well
FeOx species are present on the surface of the catalysts, which are dispersed on the surface of γ-Al2O3 support, and there are relatively
easily accessible for reagents. For the catalysts with higher Fe/Pt strong interactions between FeOx and Pt nanoparticles, which are
atom ratios, the excessive FeOx species may cover a portion of able to adjust the redox properties of the Pt-FeOx/Al2O3 catalysts.
active sites located at the boundaries between FeOx and Pt By selecting appropriate Fe/Pt ratios, highly active Pt-1.0FeOx/Al2O3
nanoparticles, thus resulting in the decrease in catalytic activity for catalyst could be obtained, which could achieve complete oxidation
the oxidation of formaldehyde.
of formaldehyde at ambient conditions. The excellent catalytic
Recently, the enhanced role of water on the low-temperature property of Pt-1.0FeOx/Al2O3 catalyst should be mainly attributed to
oxidation of CO over the supported Pt/FeOx catalysts has been the formation of more accessible active sites located at the
discussed by using in situ DRIFT characterization means.33 It was boundaries between Pt nanoparticles and FeOx species.
proposed that introducing water to the reactant stream could be
beneficial to the formation of hydroxylated oxide surface through
Acknowledgement
coadsorption of water and oxygen on the surface of the Pt/FeOx
catalyst, which might be a critical factor in improving the capability
of the supported noble metal catalysts for activating molecular
oxygen. For the oxidation of HCHO, it was reported that the
presence of moisture may promote the conversion of the
intermediates (such as formates) into CO2 and H2O,45-47 thus
resulting in the improvement of HCHO oxidation over some
supported noble metal catalysts.
This work was supported by the National Science Foundation of
China (Grant No. 20973080 and 21473074)
Notes and references
1
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In the present work, it was found that the catalytic activity of
the Pt-FeOx/Al2O3 catalyst for HCHO oxidation can also been
promoted by introducing water vapor into the feed. On the basis of
the previous work mentioned above as well as some related
literatures,38,48,49 it can be proposed that the introduced H2O
molecules are easily transformed to –OH groups by interacting with
the FeOx speices located at the surface of Pt-FeOx/Al2O3 catalysts.
And the resultant –OH groups located at the interface of Pt
nanoparticles and FeOx species (like Fe3+-OH-Pt) may act as
additional active sites for the oxidation of HCHO or the
intermediates (like formates) to produce CO2 and H2O, thus
improving the catalytic activity of the Pt-FeOx/Al2O3 catalyst for low-
temperature oxidation of HCHO. Besides, the presence of water or
surface hydroxyl groups may also be particularly suitable for the
adsorption/activation of HCHO through hydrogen bonding
interaction, which can certainly play a positive role in improving the
catalytic activity of the Pt-FeOx/Al2O3 catalyst. More
characterization work is still required to reveal the reaction
mechanism of formaldehyde oxidation and the concreted role of
water in influencing the catalytic properties of the Pt-FeOx/Al2O3
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4 Conclusions
In this study, Pt-FeOx/Al2O3 catalysts with different Fe/Pt atom
ratios were prepared by using commercial γ-Al2O3 as support, and
their catalytic properties were investigated for the low-temperature
6 | J. Name., 2012, 00, 1-3
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