Effect of alloy composition on dispersion stability and catalytic activity for NO oxidation over alumina-supported Pt–Pd catalysts

Graham, George W.; Jen, Hung-Wen; Ezekoye, Obiefune K.; Kudla, Robert; Wang, Chun; Pan, Xiaoqing; McCabe, Robert W.

doi:10.1007/s10562-007-9124-7

Cited by 82 publications

(92 citation statements)

References 16 publications

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“…Pd was selected as the precious metal owing to its low cost in comparison with Pt and Rh, which provides a strong incentive for its use in commercial applications. However, while Pd is reasonably active for NO x reduction, it is possesses poor activity for NO oxidation [22,23]. However, if Pd can be augmented by a base metal such as Mn, which is active in NO oxidation, then the opportunity might exist to decrease or even eliminate the use of Pt in LNT catalysts.…”

Section: Introductionmentioning

confidence: 99%

NO storage and reduction properties of model manganese-based lean NO trap catalysts

Zhang

Chen

Wang

et al. 2015

Applied Catalysis B: Environmental

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a b s t r a c tIn order to study the role of manganese in LNT catalysis, model Pd/Mn/Ba/Al, Pd/Mn/Al and Pd/Ba/Al catalysts were prepared and characterized. Both Mn-containing catalysts exhibited higher activity for NO oxidation to NO 2 than the Pd/Ba/Al reference catalyst, although NO x -TPD experiments showed that adsorbed NO x species were weakly bound on Pd/Mn/Al. Consequently, the presence of Ba was essential for high storage capacity. Compared to the Pd/Ba/Al reference, Pd/Mn/Ba/Al showed significantly improved NO x conversion under lean-rich cycling conditions as a consequence of its increased activity for NO oxidation and hence, superior NO x storage efficiency. In addition, the presence of Mn greatly lessened the inhibiting effects of H 2 O and CO 2 on cycle-averaged NO x conversion, this being due to the facile decomposition of manganese carbonate at low temperatures as evidenced by DRIFTS. Significantly, the Pd/Mn/Ba/Al catalyst displayed comparable activity to a traditional LNT catalyst of the Pt/Ba/Al type, showing the promising prospect of such new type of LNT catalysts.

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Section: Introductionmentioning

confidence: 99%

NO storage and reduction properties of model manganese-based lean NO trap catalysts

Zhang

Chen

Wang

et al. 2015

Applied Catalysis B: Environmental

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“…The design of task-specific ionic liquids is highly emphasized, and series task-specific ionic liquids have been synthesized in recent years [9][10][11][12]. The acidic ionic liquids are of great value because of their potential to replace the traditional acidic catalyst in industry [13]. The BrØnsted acidic ionic liquids display fine characteristic in catalytic reactions, moreover, the -SO 3 H functionalized acidic ionic liquids are more effective than other BrØnsted acidic ionic liquids in esterification, etherification, Pinacol rearrangement reactions, and some other reactions [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Density functional theory study on the –SO3H functionalized acidic ionic liquids

2009

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In this work, the structures of the -SO 3 H functionalized acidic ionic liquid 1-(3-sulfonic acid) propyl-3-methylimidazolium hydrogen sulfate ([C 3 SO 3 Hmim]HSO 4 ), including its precursor compound (zwitterion), cation, and cation-anion ion-pairs, were optimized systematically by the DFT theory at B3LYP/6-311??G** level, and their most stable geometries were obtained. The calculation results indicated that a great tendency to form strong intramolecular hydrogen bonds was present in the zwitterion, and this tendency was weakened in the cation that was the protonation product of zwitterion. The intramolecular hydrogen bonds and intermolecular hydrogen bonds coexisted in the ionic liquid, and they played an important role in the stability of the systems. The strongest interaction in the ionic liquid was found between the anion and the functional group. The transition state research and the intrinsic reaction coordinate analysis of the hydrogen transfer reaction showed that, when the cation and the anion interacted near the functional group by double O-HÁÁÁO hydrogen bonds, the ionic liquid was inclined to exist in a form of the zwitterion and H 2 SO 4 .

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“…In the Pt-Pd catalyst system, it has been reported that the noble metal components, namely, platinum oxide and palladium oxide, were converted to bimetallic particles or Pd-Pt core-shell structured grains by aging after annealing at high temperature, and these particles/ grains were larger than their initial sizes. (22)(23)(24)27) In the Pt, Pd, Au/SnO 2 gas sensor system, the aging and local heat generated from VOC oxidation would induce the grain growth of Pt and Pd. Thus, the VOC sensing properties of the Pt, Pd, Au/SnO 2 system would depend on the dispersibilities of the noble metal particles.…”

Section: Results Of Tpre Analysismentioning

confidence: 99%

Analysis of Recovery Time of Pt-, Pd-, and Au-Loaded SnO2 Sensor Material with Nonanal as Large-Molecular-Weight Volatile Organic Compounds

2016

Sensors and Materials

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We investigated the recovery times of Pt-, Pd-, and Au-loaded SnO 2 (Pt, Pd, Au/SnO 2 ) semiconductor gas sensors after their exposure to nonanal as large-molecular-weight volatile organic compounds. The sensors were characterized by their response and temperature-programmed reaction (TPRe), and by transmission electron microscopy (TEM) observation. Sensors pretreated by sufficient aging showed good response but poor resistance recovery with nonanal, whereas good resistance recovery was observed with isoprene. The TPRe analysis revealed that aldehyde gas molecules were oxidized to carboxylic acids on the sensors at the sensor working temperature. In sufficiently aged Pt, Pd, and Au/SnO 2 sensors, the loaded Pt, Pd, and Au catalysts were observed to aggregate by TEM. From these results, we suggest different dispersion states of the loaded Pt, Pd, and Au noble metal particles, the mechanism of oxidation and adsorption of nonanal molecules on SnO 2 grain surface, and their relationship to the recovery time after exposure to nonanal.

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Effect of alloy composition on dispersion stability and catalytic activity for NO oxidation over alumina-supported Pt–Pd catalysts

Cited by 82 publications

References 16 publications

NO storage and reduction properties of model manganese-based lean NO trap catalysts

NO storage and reduction properties of model manganese-based lean NO trap catalysts

Density functional theory study on the –SO3H functionalized acidic ionic liquids

Analysis of Recovery Time of Pt-, Pd-, and Au-Loaded SnO2 Sensor Material with Nonanal as Large-Molecular-Weight Volatile Organic Compounds

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