Investigation of Oxide‐type Oxidation Catalysts by Reactions of Oxygen Isotopic Exchange

Боресков, Г. К.; Muzykantov, V.S.

doi:10.1111/j.1749-6632.1973.tb51065.x

Cited by 90 publications

(59 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The initial RS spectrum after calcination in 16 O 2 is also characterized by three Raman peaks at 1030, 1010, and 880 cm -1 . These Raman peaks decrease in intensity after reducing the sample with butane, followed by recalcination in 18 O 2 at 450°C.…”

Section: Resultsmentioning

confidence: 99%

“…The spectrum obtained after calcination in 16 O 2 is shown in Figure 2. The spectrum is dominated by three strong Raman peaks at 1030, 1010, and 880 cm -1 , which were previously assigned to terminal CrdO vibrations of monochromate (1030 cm -1 ) and terminal CrdO and bridging Cr-O-Cr vibrations of polychromate species (1010 and 880 cm -1 ), respectively.…”

Section: Resultsmentioning

confidence: 99%

“…The present oxygen-18 isotopic exchange experiments provide fundamental information about the number of terminal CrdO bonds, mono-oxo versus di-oxo (see Figure 1), present in the isolated and polymerized surface chromium oxide species. For the supported chromium oxide catalysts containing comparable amounts of the two oxygen isotopes, a mono-oxo should give rise to two strong vibrations, Crd 16 O and Crd 18 O, and a di-oxo structure should exhibit three strong vibrations, 16 OdCrd 16 O, 18 OdCrd 18 O, and 16 OdCrd 18 O, the latter is expected to be predominant. Furthermore, a Raman peak [ 16 For the isolated surface chromium oxide species, two weak Raman peaks are observed at 1030 and 990 cm -1 , and the third band for a di-oxo structure would be expected at around 1010 cm -1 .…”

Section: Resultsmentioning

confidence: 99%

“…The oxygen-18-exchanged RS spectra of the 5 wt % CrO 3 /Al 2 O 3 catalyst, obtained after successive butane reduction-18 O 2 oxidation cycles are also very similar (not shown for brevity). The initial RS spectrum after calcination in 16 In addition, 18 O 2 reoxidizes the reduced Cr n+ species (obtained after reduction with butane) on the support, according to with n indicating oxidation state (n < 6) and s, surface.…”

Section: Resultsmentioning

confidence: 99%

“…

…”

mentioning

confidence: 99%

See 4 more Smart Citations

In SituRaman Spectroscopy of Supported Chromium Oxide Catalysts: ¹⁸O₂−¹⁶O₂Isotopic Labeling Studies

Weckhuysen

Wachs

1997

J. Phys. Chem. B

View full text Add to dashboard Cite

The isothermal isotopic exchange reaction of 18 O 2 with 16 O of chromium(VI) oxide supported on zirconia, alumina, and titania has been investigated with in situ laser Raman spectroscopy. The isotopic exchange reaction is dependent on the support type, the Cr loading, and the reaction temperature. Complete isotopic exchange of chromium(VI) oxide with 18 O 2 is difficult to achieve and requires several successive butane reduction-18 O 2 oxidation cycles at relatively high temperatures. The efficiency of the isothermal isotopic exchange reaction increases from alumina over titania to zirconia and with increasing Cr loading and reduction temperature. The observed Raman shifts upon isotopic labeling are consistent with a mono-oxo surface chromium oxide(VI) species.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…

…”

mentioning

confidence: 99%

See 3 more Smart Citations

In SituRaman Spectroscopy of Supported Chromium Oxide Catalysts: ¹⁸O₂−¹⁶O₂Isotopic Labeling Studies

Weckhuysen

Wachs

1997

J. Phys. Chem. B

View full text Add to dashboard Cite

show abstract

High‐temperature Corrosion of Metals by Gases

Grabke

Holzäpfel

2003

Encyclopedia of Electrochemistry

View full text Add to dashboard Cite

The sections in this article are Introduction Determination of Thermodynamic Data Measurements of Gibbs Energies Measurement and Control of Partial Pressures and Activities Nonstoichiometry and Defect Structure of Oxides and Other Corrosion Products Cation‐deficient Oxides Ni O Co O Fe O Cu 2 O Cation‐excess Oxides Zn O Ti O 2 and Zr O 2 Chromia and Alumina Cr 2 O 3 Al 2 O 3 Sulfides Manganous Sulfide Ag 2 S Fe S and Ni S Mechanisms and Kinetics of High‐temperature Scale Formation Surface Reaction Control (Linear Rate Law) Linear Oxidation in CO 2 – CO Mixtures Linear Oxidation in H 2 O  H 2 Mixtures Linear Oxidation in O 2 Linear Sulfidation in H 2 S  H 2 Bulk Diffusion Control–Parabolic Kinetics Transition from Linear to Parabolic Kinetics Wagner's Theory of Oxidation Diffusion‐controlled Growth of Some Oxides Validity Range of Wagner's Theory Theory of Thin Film Growth Theory of Cabrera and Mott Field Caused by Chemisorption Field Effect on the Reactions at the Metal/Oxide and Gas/Oxide Interfaces Interfacial Reactions During Scale Growth Evidence on the Reactions at the Scale/Metal Interface Local Cell Action in High‐temperature Corrosion

show abstract

Generation of Reactive Oxygen Species on Au/TiO₂ after Treatment with Hydrogen: Testing the Link to Ethanol Low‐Temperature Oxidation

2011

View full text Add to dashboard Cite

The gold catalyzed aerobic oxidation of alcohols is currently of great interest for the following reasons: 1) biomass-derived alcohols are a promising, renewable organic feedstock; 2) they use cheap, green oxidants, such as molecular oxygen (air); and 3) gold catalysts show extraordinarily high activities under mild conditions. [1][2][3][4] The mechanistic aspects of gold catalyzed oxidation reactions of CO, H 2 , and other small molecules have been extensively studied, [1,[5][6] but a generally accepted oxidation mechanism for alcohols under similar conditions has not yet been formulated (however, see references [7][8][9][10]). Notably, the efficient low-temperature (50-120 8C) gold catalyzed oxidation of alcohols is known to proceed only in the liquid phase during the course of a long-term batch reaction with high oxygen pressure or intensive O 2 flow. [1][2][3][4] On the other hand, we recently found that metallic gold nanoparticles supported on TiO 2 gave rise to "double peak" catalytic activity in the gasphase oxidation of ethanol to acetaldehyde. [11] The temperature, at which the first peak of activity occurred, 120 8C, was unusually low for the gas-phase reaction of primary alcohols. In contrast, gold supported on Al 2 O 3 and SiO 2 showed more usual behaviors, which were analogous to the second peak activity of Au/TiO 2 at temperatures above 200 8C. [11] To account for these results, we proposed that specific active oxygen species form on the Au/TiO 2 surface under mild reaction conditions and suggested hydrogen as a probable cofactor in their generation. Indeed, H 2 can be produced concurrently as a result of ethanol anaerobic dehydrogenation and can thus participate in catalytic activity. [11][12][13] In the present work, our efforts were focused on the role of hydrogen in the catalytic activity of gold supported on TiO 2 , Al 2 O 3 , and SiO 2 matrixes to provide insights into the different profiles of ethanol oxidation. [11] For this purpose, the O 2 iso-tope exchange technique was applied in order to estimate the relative activity of the surface oxygen species.Oxygen isotope exchange (OIE) is a very sensitive direct method for evaluating the reactivity of surface oxygen atoms, which is a subject of primary interest in heterogeneous oxidation catalysis. Usually, as in the case of metal oxides, OIE is observed at 220-700 8C, although some metal oxides induce OIE at low temperatures after calcination and cooling in a vacuum. [14] A highly reactive oxygen species, so called aoxygen, is generated on the Fe-ZSM5 zeolite surface after treatment with N 2 O. These species readily oxidize organics (benzene, methane, etc.) as well as perform OIE at room temperature. [15] A special but relevant case, although photoinduced, is the OIE over TiO 2 , which also occurs at room temperature due to the involvement of reactive oxygen species, probably O À anion radicals. [16] Notably, a correlation was found between the TiO 2 activity for the photoinduced OIE and the oxidation of isobutane, methanol, and ethanol over ...

show abstract

Investigation of Oxide‐type Oxidation Catalysts by Reactions of Oxygen Isotopic Exchange

Cited by 90 publications

References 10 publications

In SituRaman Spectroscopy of Supported Chromium Oxide Catalysts: ¹⁸O₂−¹⁶O₂Isotopic Labeling Studies

In SituRaman Spectroscopy of Supported Chromium Oxide Catalysts: ¹⁸O₂−¹⁶O₂Isotopic Labeling Studies

High‐temperature Corrosion of Metals by Gases

Generation of Reactive Oxygen Species on Au/TiO₂ after Treatment with Hydrogen: Testing the Link to Ethanol Low‐Temperature Oxidation

Contact Info

Product

Resources

About

Investigation of Oxide‐type Oxidation Catalysts by Reactions of Oxygen Isotopic Exchange

Cited by 90 publications

References 10 publications

In SituRaman Spectroscopy of Supported Chromium Oxide Catalysts: 18O2−16O2Isotopic Labeling Studies

In SituRaman Spectroscopy of Supported Chromium Oxide Catalysts: 18O2−16O2Isotopic Labeling Studies

High‐temperature Corrosion of Metals by Gases

Generation of Reactive Oxygen Species on Au/TiO2 after Treatment with Hydrogen: Testing the Link to Ethanol Low‐Temperature Oxidation

Contact Info

Product

Resources

About

In SituRaman Spectroscopy of Supported Chromium Oxide Catalysts: ¹⁸O₂−¹⁶O₂Isotopic Labeling Studies

In SituRaman Spectroscopy of Supported Chromium Oxide Catalysts: ¹⁸O₂−¹⁶O₂Isotopic Labeling Studies

Generation of Reactive Oxygen Species on Au/TiO₂ after Treatment with Hydrogen: Testing the Link to Ethanol Low‐Temperature Oxidation