The effect of platinum on the reducibility of Rh oxides on CeZr modified alumina supported automotive catalysts

Polvinen, R.; Vippola, Minnamari; Valden, M.; Lepistö, Toivo; Suopanki, Aslak; Härkönen, Matti

doi:10.1002/sia.1752

Cited by 18 publications

(25 citation statements)

References 19 publications

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“…The synergism exerted on account of bimetallic Pt-Rh formation is similar with the already reported results. 18,20 As, all the catalysts exhibit 100% conversion between 400 and 550 o C, they may posses coke tolerance; even at low Pt-Rh composition, well-separated solo metallic particles also confer coke tolerance to the catalyst.…”

Section: Resultsmentioning

confidence: 99%

“…15 The effect of bimetallic Pt-Rh alloy formation depicts that Pt oxidizes hydrocarbons and byproducts, formed during combustion while rhodium reduces nitric oxides to nitrogen. Therefore, in our study, we synthesized bimetallic Pt-Rh and trimetallic Pt-Rh-Pd catalyst and investigated methane combustion.…”

Section: Introductionmentioning

confidence: 99%

“…Previous reports on bimetallic alloy, 18,19 rendered that the metal composition as well as the metal-support interaction influence alloy formation which perhaps alters the catalytic activity. 20 Taking this into account, we tried various combinations of noble metal composition to obtain binary and ternary alloys of Pt, Rh and Pd on different supports for methane combustion. The effect of catalytic supports such as Al2O3, TiO2 and ZrO2 in alloy formation and its impact on combustion was also explored.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Bimetallic Pt-Rh and Trimetallic Pt-Pd-Rh Catalysts for Low Temperature Catalytic Combustion of Methane

Bhagiyalakshmi¹,

Anuradha²,

Park³

et al. 2010

Bulletin of the Korean Chemical Society

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Monometallic, bimetallic and trimetallic particles consisting of different weight compositions of Pt-Pd-Rh over pure alumina wash coats have been synthesized and their catalytic performance on methane conversion was studied from 150 to 600 o C. Different catalyst formulations with variable Pt, Pd and Rh contents for bimetallic and trimetallic systems were tried and Pt(1.5)Rh(0.3)/Al2O3 and Pt(1.0)Pd(1.0)Rh(0.3)/Al2O3 shows low T50 and T90 temperatures. Bimetallic and trimetallic particle synergism acts as three way catalysts and therefore, all the catalysts show 100% methane conversion. The effect of supports such as ZrO2 and TiO2 on methane combustion was investigated; from T50 and T90 results both Al2O3 and ZrO2 are suitable supports for low temperature methane combustion.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Bimetallic Pt-Rh and Trimetallic Pt-Pd-Rh Catalysts for Low Temperature Catalytic Combustion of Methane

Bhagiyalakshmi¹,

Anuradha²,

Park³

et al. 2010

Bulletin of the Korean Chemical Society

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“…A high Rh content has been reported to reduce PM particle growth, presumably due to the lower vapor pressure of Rh 2 O 3 than PtO 2 [6,9,15]. These two catalyst formulations had identical amounts of Pt and Rh initially separated in different washcoat layers but have drastically different particle size and composition distributions following identical aging treatments.…”

Section: Discussionmentioning

confidence: 97%

“…The average PM particle sizes for Ptonly and Pt-Rh catalysts were found to be larger in support materials containing CeO 2 and Al 2 O 3 compared to Al 2 O 3 alone [6]. Ceria has been reported to promote PM particle growth in the presence of water vapor [7].…”

Section: Introductionmentioning

confidence: 98%

Comparative Analytical Study of Two Pt–Rh Three-way Catalysts

Hangas

Chen

2006

Catal Lett

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Pt-Rh three-way catalysts (TWCs) of two formulations were examined by electron probe microanalysis (EPMA) and cross sectional transmission electron microscopy (TEM), in order to study the effect of accelerated aging on microstructure. Both formulations have Pt and Rh applied in separate washcoat layers, Rh in a zirconia-rich outer layer and Pt in an alumina-rich inner layer(s). Microstructural analyses show that in spite of the initial separation, the precious metals inter-diffuse between the washcoat layers and alloy during aging. Following dynamometer aging the two formulations exhibited significant differences in the precious metal (PM) particle size distributions and the correlation between PM particle size and composition. These differences are attributed to the increased transport of Pt due to the presence of ceria and zirconia in the alumina-rich inner washcoat of one formulation, compared to other formulation. The presence or absence of porosity > 1lm in diameter and differences in initial Pt distributions in the inner washcoat were also noted as possibly contributing to the PM particle growth. The transition alumina of one formulation, containing Ba, partially transformed to corundum during aging. The other formulation utilized a La-stabilized alumina which did not transform to corundum after aging.

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Hydroxyl Assisted Rhodium Catalyst Supported on Goethite Nanoflower for Chemoselective Catalytic Transfer Hydrogenation of Fully Converted Nitrostyrenes

Liu

et al. 2019

Adv Synth Catal

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Control of chemoselectivity is a special challenge for the reduction of nitroarenes bearing one or more unsaturated groups. Here, we report a flower‐like Rh/α‐FeOOH catalyst for the chemoselective hydrogenation of nitrostyrene to vinylaniline over full conversion, which benefits the new functionalized aminostyrene because the multisubstituted aminostyrenes are usually commercially unavailable. This catalyst does not only show desirable selectivity for the vinylanilines, but also exhibits the inertness to various other reducible groups over wide reaction duration. The catalytic selectivity for the reduction of the nitro group towards vinyl group was investigated by the control experiments and FT‐IR analysis. We have found that the abundant hydroxyl groups in the α‐FeOOH may contribute to the improvement of catalytic activity and selectivity. Furthermore, the catalyst exhibits excellent stability and keeps its catalytic performance even after 6 cycles.

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The effect of platinum on the reducibility of Rh oxides on CeZr modified alumina supported automotive catalysts

Cited by 18 publications

References 19 publications

Effect of Bimetallic Pt-Rh and Trimetallic Pt-Pd-Rh Catalysts for Low Temperature Catalytic Combustion of Methane

Effect of Bimetallic Pt-Rh and Trimetallic Pt-Pd-Rh Catalysts for Low Temperature Catalytic Combustion of Methane

Comparative Analytical Study of Two Pt–Rh Three-way Catalysts

Hydroxyl Assisted Rhodium Catalyst Supported on Goethite Nanoflower for Chemoselective Catalytic Transfer Hydrogenation of Fully Converted Nitrostyrenes

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