Marked addition effect of Re upon the water gas shift reaction over TiO2 supported Pt, Pd and Ir catalysts

Satô, Yasushi; Terada, Keisuke; Soma, Yoshinori; Miyao, Toshihiro; Naito, Shuichi

doi:10.1016/j.catcom.2005.08.009

Cited by 26 publications

(27 citation statements)

References 9 publications

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“…The activation barrier calculated from the Arrhenius plots is 56.4 ± 5.0 kJ/mol. The sizes of Pd and Pt nanoparticles in current studies are similar to the sizes reported in literatures [16,[40][41][42][43][44]. Therefore it is reasonable to directly compare the apparent activation energy of Pd and Pt nanoparticles supported on a-MnO 2 to Pd and Pt supported on TiO 2 and CeO 2 reported in literatures.…”

Section: Resultssupporting

confidence: 71%

“…Obviously, not all of the surface Pd or Pt atoms participate in the WGS reaction; therefore the calculated TOF values were underestimated. Compared to the TOF of H 2 generation on CeO 2 and TiO 2 based WGS catalysts [40,41] represented in Table 4, as well as activation energies in Table 1, Pd/a-MnO 2 and Pt/a-MnO 2 catalysts exhibit a comparable activity. It is noted that pure a-MnO 2 nanorod isn't active at all for WGS reaction upon the same pretreatment in H 2 .…”

Section: Resultsmentioning

confidence: 90%

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Water–Gas Shift on Pd/α-MnO2 and Pt/α-MnO2

et al. 2015

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Low temperature water-gas shift (WGS) catalysts, Pd nanoparticles supported on a-MnO 2 nanorods termed Pd/a-MnO 2 and Pt nanoparticles supported on aMnO 2 nanorods termed Pt/a-MnO 2 were synthesized by introducing Pd or Pt precursor to well-prepared a-MnO 2 nanorods through precipitation deposition with a following annealing at 300°C. They are quite active for WGS in the temperature range of 140-350°C. Activation energies for WGS on Pd/a-MnO 2 and Pt/a-MnO 2 are 45.3 and 56.4 kJ/mol respectively, comparable to precious metal supported on CeO 2 and TiO 2 for WGS. Surface chemistries of the two catalysts during WGS were tracked with ambient pressure X-ray photoelectron spectroscopy. Different from the preservation of the surface and bulk phase of other oxide support such as CeO 2 , TiO 2 in CeO 2 -or TiO 2 -based WGS catalysts, both surface and bulk of aMnO 2 nanorods of Pd/a-MnO 2 and Pt/a-MnO 2 are transited to MnO during WGS. In-situ studies identified oxygen vacancies of the formed MnO support during WGS and the metallic state of Pd and Pt nanoparticles supported on the nonstoichiometric MnO. Graphical Abstract

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Section: Resultssupporting

confidence: 71%

Section: Resultsmentioning

confidence: 90%

Water–Gas Shift on Pd/α-MnO2 and Pt/α-MnO2

et al. 2015

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“…However, in contrast to the Pt/CeO 2 catalyst, deactivation due to Pt sintering at high temperatures during the WGS reaction has been observed for Pt/ TiO 2 catalysts [10]. Addition of Re to the Pt/TiO 2 inhibits this deactivation and improves the activity for the WGS reaction [10,[15][16][17]. In order to meet the requirement of high space velocity operation to reduce the reactor volume for onboard and small scale H 2 production, further increases in both activity and stability of the Pt/TiO 2 are highly desired.…”

Section: Introductionmentioning

confidence: 90%

“…Pt/ZrO 2 is stable for the WGS reaction, but its activity is much lower than Pt/CeO 2 [10], even though significant improvement has been achieved by addition of alkali metals [11]. Increasing attention has been paid to Pt/TiO 2 catalysts for WGS, because it shows similar or greater activity compared to Pt/ CeO 2 [10,[12][13][14][15][16][17]. However, in contrast to the Pt/CeO 2 catalyst, deactivation due to Pt sintering at high temperatures during the WGS reaction has been observed for Pt/ TiO 2 catalysts [10].…”

Section: Introductionmentioning

confidence: 97%

Significant Improvement in Activity and Stability of Pt/TiO2 Catalyst for Water Gas Shift Reaction Via Controlling the Amount of Na Addition

et al. 2008

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Na promoted Pt/TiO 2 catalysts have been studied under high severity, near equilibrium, conditions for use as a single stage WGS catalyst. Addition of 3 wt% Na to a 1 wt% Pt/TiO 2 catalyst has been found to improve water gas shift activity significantly compared to Pt/TiO 2 , Pt/CeO 2 , and Pt-Re/TiO 2 catalysts. This catalyst is stable when the reaction temperature is higher than 250°C. Deactivation occurred when the reaction temperature was lower than 250°C, however, returning the temperature to higher than 250°C fully recovered activity. TEM observations revealed that addition of Na inhibited Pt particle sintering. These results suggest that Na promoted Pt/TiO 2 is a promising single stage water gas shift catalyst for small scale hydrogen production.

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“…Precious metal monolithic catalysts have been proven successfully in automotive emission control catalysts and various other environmental applications [5]. Several attempts have been made to increase the precious metal-containing catalyst activity by using promoters [6][7][8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Effect of Mo and Re Promoters on the Activity and Stability of a Pt/ZrO2 Water-Gas Shift Catalyst (Part 1)

Ruettinger¹,

Liu²,

Xu³

et al. 2008

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The activity and stability of Pt catalysts for the water-gas shift (WGS) reaction can be profoundly influenced by the presence of promoters. We present the results on the promotion of a Pt/doped ZrO 2 catalyst by Mo and Re. The CO conversion rate of the catalysts is approximately 3-times higher in the presence of the promoters after reduction at temperatures higher than 325°C. The stability of the catalysts against sintering under reaction conditions is significantly enhanced by the promoters as well. The active phase is unstable in the presence of steam, even in presence of hydrogen at temperatures as high as 300°C but is re-formed at higher temperatures in reformate. A detailed FTIR investigation reveals that Pt-Re-Mo alloy is the active phase for the material under investigation. The alloy decomposes reversibly below 300°C, but reforms in reformate above 325°C restoring catalytic activity.

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Marked addition effect of Re upon the water gas shift reaction over TiO2 supported Pt, Pd and Ir catalysts

Cited by 26 publications

References 9 publications

Water–Gas Shift on Pd/α-MnO2 and Pt/α-MnO2

Water–Gas Shift on Pd/α-MnO2 and Pt/α-MnO2

Significant Improvement in Activity and Stability of Pt/TiO2 Catalyst for Water Gas Shift Reaction Via Controlling the Amount of Na Addition

Effect of Mo and Re Promoters on the Activity and Stability of a Pt/ZrO2 Water-Gas Shift Catalyst (Part 1)

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