Preferential CO oxidation in a H2-rich stream on Pt-ReO x/SiO2: Catalyst structure and reaction mechanism

Tatsuya Ebashi; Yoichi Ishida; Yoshinao Nakagawa; Shin Ichi Ito; Takeshi Kubota; Keiichi Tomishige

doi:10.1021/jp911908c

Preferential CO oxidation in a H₂-rich stream on Pt-ReO _x/SiO₂: Catalyst structure and reaction mechanism

Tatsuya Ebashi, Yoichi Ishida, Yoshinao Nakagawa, Shin Ichi Ito, Takeshi Kubota, Keiichi Tomishige

Research output: Contribution to journal › Article › peer-review

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Abstract

Modification of Pt/SiO₂ with ReO_x species enhanced the catalytic activity of the CO oxidation with O₂ in the presence of H₂. The amount of Re modifier on Pt-ReO_x/SiO₂ was optimized to be Re/Pt = 0.5 on the molar basis. The promoting effect of Re species appeared after the reduction above 673 K. Characterization of the reduced Pt-ReO_x/SiO₂ catalyst by means of EXAFS, XANES, temperature-programmed reduction, and CO adsorption measurements suggested the formation of the ReO_x clusters on the surface of Pt metal particles with the average valence of Re of +2.7. The CO adsorption on Pt-ReO _x/SiO₂ gave a higher wavenumber then that on Pt/SiO ₂ at the same CO coverage, showing the weakened interaction between CO and the Pt surface, which is also supported by the desorption profile of the adsorbed CO. The CO coverage on Pt-ReO_x/SiO₂ during the preferential CO oxidation was much smaller than that in the absence of H ₂, suggesting that an oxygen-containing species was coadsorbed on the reduced catalyst. The pulse reaction showed that the reduced Pt-ReO _x/SiO₂ can activate O₂ even when the catalyst surface is saturated with CO. These tendencies can be explained by the mechanism where the reduced ReO_x species activates O₂ and the oxidizing species is spilled over from the ReO_x species to the Pt surface.

Original language	English
Pages (from-to)	6518-6526
Number of pages	9
Journal	Journal of Physical Chemistry C
Volume	114
Issue number	14
DOIs	https://doi.org/10.1021/jp911908c
Publication status	Published - 2010 Apr 15
Externally published	Yes

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Energy(all)
Physical and Theoretical Chemistry
Surfaces, Coatings and Films

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10.1021/jp911908c

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title = "Preferential CO oxidation in a H2-rich stream on Pt-ReO x/SiO2: Catalyst structure and reaction mechanism",

abstract = "Modification of Pt/SiO2 with ReOx species enhanced the catalytic activity of the CO oxidation with O2 in the presence of H2. The amount of Re modifier on Pt-ReOx/SiO2 was optimized to be Re/Pt = 0.5 on the molar basis. The promoting effect of Re species appeared after the reduction above 673 K. Characterization of the reduced Pt-ReOx/SiO2 catalyst by means of EXAFS, XANES, temperature-programmed reduction, and CO adsorption measurements suggested the formation of the ReOx clusters on the surface of Pt metal particles with the average valence of Re of +2.7. The CO adsorption on Pt-ReO x/SiO2 gave a higher wavenumber then that on Pt/SiO 2 at the same CO coverage, showing the weakened interaction between CO and the Pt surface, which is also supported by the desorption profile of the adsorbed CO. The CO coverage on Pt-ReOx/SiO2 during the preferential CO oxidation was much smaller than that in the absence of H 2, suggesting that an oxygen-containing species was coadsorbed on the reduced catalyst. The pulse reaction showed that the reduced Pt-ReO x/SiO2 can activate O2 even when the catalyst surface is saturated with CO. These tendencies can be explained by the mechanism where the reduced ReOx species activates O2 and the oxidizing species is spilled over from the ReOx species to the Pt surface.",

author = "Tatsuya Ebashi and Yoichi Ishida and Yoshinao Nakagawa and Ito, {Shin Ichi} and Takeshi Kubota and Keiichi Tomishige",

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T2 - Catalyst structure and reaction mechanism

AU - Ebashi, Tatsuya

AU - Ishida, Yoichi

AU - Nakagawa, Yoshinao

AU - Ito, Shin Ichi

AU - Kubota, Takeshi

AU - Tomishige, Keiichi

PY - 2010/4/15

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N2 - Modification of Pt/SiO2 with ReOx species enhanced the catalytic activity of the CO oxidation with O2 in the presence of H2. The amount of Re modifier on Pt-ReOx/SiO2 was optimized to be Re/Pt = 0.5 on the molar basis. The promoting effect of Re species appeared after the reduction above 673 K. Characterization of the reduced Pt-ReOx/SiO2 catalyst by means of EXAFS, XANES, temperature-programmed reduction, and CO adsorption measurements suggested the formation of the ReOx clusters on the surface of Pt metal particles with the average valence of Re of +2.7. The CO adsorption on Pt-ReO x/SiO2 gave a higher wavenumber then that on Pt/SiO 2 at the same CO coverage, showing the weakened interaction between CO and the Pt surface, which is also supported by the desorption profile of the adsorbed CO. The CO coverage on Pt-ReOx/SiO2 during the preferential CO oxidation was much smaller than that in the absence of H 2, suggesting that an oxygen-containing species was coadsorbed on the reduced catalyst. The pulse reaction showed that the reduced Pt-ReO x/SiO2 can activate O2 even when the catalyst surface is saturated with CO. These tendencies can be explained by the mechanism where the reduced ReOx species activates O2 and the oxidizing species is spilled over from the ReOx species to the Pt surface.

AB - Modification of Pt/SiO2 with ReOx species enhanced the catalytic activity of the CO oxidation with O2 in the presence of H2. The amount of Re modifier on Pt-ReOx/SiO2 was optimized to be Re/Pt = 0.5 on the molar basis. The promoting effect of Re species appeared after the reduction above 673 K. Characterization of the reduced Pt-ReOx/SiO2 catalyst by means of EXAFS, XANES, temperature-programmed reduction, and CO adsorption measurements suggested the formation of the ReOx clusters on the surface of Pt metal particles with the average valence of Re of +2.7. The CO adsorption on Pt-ReO x/SiO2 gave a higher wavenumber then that on Pt/SiO 2 at the same CO coverage, showing the weakened interaction between CO and the Pt surface, which is also supported by the desorption profile of the adsorbed CO. The CO coverage on Pt-ReOx/SiO2 during the preferential CO oxidation was much smaller than that in the absence of H 2, suggesting that an oxygen-containing species was coadsorbed on the reduced catalyst. The pulse reaction showed that the reduced Pt-ReO x/SiO2 can activate O2 even when the catalyst surface is saturated with CO. These tendencies can be explained by the mechanism where the reduced ReOx species activates O2 and the oxidizing species is spilled over from the ReOx species to the Pt surface.

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Preferential CO oxidation in a H₂-rich stream on Pt-ReO _x/SiO₂: Catalyst structure and reaction mechanism

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