Preferential CO oxidation in hydrogen-rich stream over Pt catalysts modified with alkali metals

Tanaka, Hisanori; Kuriyama, Masatoshi; Ishida, Yōichi; Ito, Shin‐ichi; Tomishige, Keiichi; Kunimori, Kimio

doi:10.1016/j.apcata.2008.03.030

Cited by 53 publications

(36 citation statements)

References 37 publications

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“…Grabow et al 29 studied water-gas shift reaction by density functional theory (DFT) calculations and suggested that the reaction path could be limited by the low concentration of surface OH. Tanaka et al 45 suggested that the coadsorbed species originating from H 2 and O 2 (e.g., the OH species) under the PROX condition can promote the CO oxidation. Xu et al 46 provided direct evidence for the interfacial CO ads + OH ads reaction to produce CO 2 at the platinum-oxide interface at low temperatures.…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

Microkinetic Study of CO Oxidation and PROX on Ir−Fe Catalyst

Li¹,

Wang²,

Zhang³

et al. 2011

Ind. Eng. Chem. Res.

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A microkinetic analysis of the preferential oxidation of CO in H 2 over Ir-Fe/SiO 2 catalyst is reported. Based on the results of in situ diffuse reflectance infrared spectroscopy, microcalorimetry, Mössbauer spectroscopy, and steady-state kinetic experiments in a microreactor, a microkinetic model is proposed that predicts the experimental results well. The model suggests that the reaction between adsorbed H and O for the formation of OH is rate-limiting for the PROX reaction, whereas the surface reaction between adsorbed CO and O is rate-determining for CO oxidation. In addition, the model predicts that the oxidation of adsorbed CO by surface OH is the dominant pathway for the PROX reaction. The surface coverages of different intermediates are also predicted by the model. According to this model, we can conclude that the presence of H 2 increases the surface concentration of OH and, hence, lowers the activation energy and increases the rate of the PROX reaction.

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Section: Simulation Results and Discussionmentioning

confidence: 99%

Microkinetic Study of CO Oxidation and PROX on Ir−Fe Catalyst

Li¹,

Wang²,

Zhang³

et al. 2011

Ind. Eng. Chem. Res.

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“…Noble metals including Pt, Rh, Pd and Au as active catalysts have been proposed for PROX of CO [2][3][4][5][6]. However, precious metal catalysts have disadvantages of high cost and limited availability.…”

Section: Introductionmentioning

confidence: 99%

Effect of Cobalt on the Activity of CuO/CeO2 Catalyst for the Selective Oxidation of CO

et al. 2010

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In this work effect of cobalt on catalyst CuO/ CeO 2 activity in selective CO oxidation in H 2 -containing gases mixture was investigated. Catalysts were prepared by wet impregnation and calcination at 673 K, characterized by ICP, H 2 -TPR, XRD, TEM, BET and XPS. The addition of cobalt to Cu/CeO 2 catalyst improved the catalytic activity and selectivity for CO oxidation. Discussion of the results showed that the synergistic effect is correlated to better dispersion and reducibility of copper in the presence of the cobalt metal additive. More precisely, cobalt enhanced the segregation of copper phase towards the catalyst surface and copper enhanced CO oxidation at the expense of H 2 combustion.

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“…158 Interestingly, it seems that the promotional effect of K is more pronounced on the inert-oxidesupported Pt catalysts than that on the reducible-oxidesupported ones. Tanaka et al 162 observed that K−Pt/Al 2 O 3 and K−Pt/SiO 2 exhibited a much higher CO conversion and CO 2 (Figure 3a). Therefore, the desorption of CO from the surface or the adsorption of O 2 is proposed as the rate-determining step on the nonpromoted PGM catalysts.…”

Section: Promoted Pgm Catalysts For the Proxmentioning

confidence: 99%

Recent Advances in Preferential Oxidation of CO Reaction over Platinum Group Metal Catalysts

2012

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Preferential oxidation of CO (PROX) is an important reaction for removing small amounts of CO to a parts-per-million level from the hydrogen-rich stream, which will be ultimately supplied as a fuel to polymer−electrolyte membrane fuel cells. The key to the application of PROX is to develop a highly active and selective catalyst that operates well in a wide temperature window (e.g., 80−180°C) and has good resistance to CO 2 and steam. In the past decades, various catalyst formulations have been developed, among which platinum group metal catalysts, including Pt, Ru, and Irin particular, those modified with promoters such as alkali metals and reducible metal oxideshave received a great deal of attention for their significantly improved catalytic activities in the low-temperature range. In this minireview, the recent advances of the platinum group metal catalysts for the PROX reaction are summarized, including performances of unpromoted and promoted catalysts, reaction mechanisms, and kinetics. In addition, the important roles of hydroxyl groups in the PROX reaction are also discussed.

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Preferential CO oxidation in hydrogen-rich stream over Pt catalysts modified with alkali metals

Cited by 53 publications

References 37 publications

Microkinetic Study of CO Oxidation and PROX on Ir−Fe Catalyst

Microkinetic Study of CO Oxidation and PROX on Ir−Fe Catalyst

Effect of Cobalt on the Activity of CuO/CeO2 Catalyst for the Selective Oxidation of CO

Recent Advances in Preferential Oxidation of CO Reaction over Platinum Group Metal Catalysts

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