Roles of ZrO2 in SO2-poisoned Pd/(Ce-Zr)O2 catalysts for CO oxidation

Ryou, YoungSeok; Lee, Jaeha; Lee, Hyokyoung; Choung, Jin Woo; Yoo, Seungbeom; Kim, Do Heui

doi:10.1016/j.cattod.2015.02.009

Cited by 29 publications

(14 citation statements)

References 54 publications

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“…This phenomenon occurs in most cases of CH 4 oxidation catalysts even with the most effective regeneration treatments, combined with other causes, such as structural loss and active phase transformation. 31,179,194,237,251,261 It should be mentioned that H 2 O has a promoting effect on the desulfation of sulfated CH 4 oxidation catalysts in the reducing CH 4 atmosphere, resembling the findings for sulfated DOC or NSR when H 2 is used as the dominant reductant. 240,249,250 It is proposed that the destabilizing effect of water on aluminum sulfate (which transforms into instable Al 2 O 2 SO(OH) owning lower desorption energy) or on rhodium sulfate (for Rh/ZSM-5) facilitates sulfate removal.…”

Section: Doc Working Architecture/functionalitiessupporting

confidence: 53%

“…125,126,174,265 Combining the sintering caused by sulfur and hydrothermal aging under harsh operational conditions of DOCs, sintering barriers like La 2 O 3 , ZrO 2 , and CeO 2 or highly stable/acidic supports like SiO 2 , Al 2 O 3 , or their mixtures are favored. 194,236,261,266 Specifically, ZrO 2 is a necessary component to strengthen support robustness via Zr−O−M (M = Ce, Al, Si etc.) bond formation with CeO 2 , Al 2 O 3 , and SiO 2 .…”

Section: Doc Working Architecture/functionalitiesmentioning

confidence: 99%

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A Review on the Impact of SO₂ on the Oxidation of NO, Hydrocarbons, and CO in Diesel Emission Control Catalysis

et al. 2021

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A high-efficiency after-treatment technology has been required to meet the increasingly stringent regulations on the emissions of nitrogen oxides (NO x ), hydrocarbons (HCs), and carbon monoxide (CO) exhausts from diesel engine vehicles throughout the world. The diesel oxidation catalyst (DOC) is an indispensable part of a diesel-fueled exhaust system, which mainly functions in the oxidation of unburned HCs and CO to CO2 and H2O (in the case of HCs) and a proportion of NO to NO2. However, the DOC will unavoidably be poisoned by trace gaseous SO2 or accumulated sulfur on the catalyst under real operational conditions and hence impair the overall purification efficiency of the aftertreatment system. There have been significant research efforts from both academia and industry involving sulfur-relevant diesel oxidation chemistry and development of robust sulfur-resistant oxidation catalysts. This Review focuses on recent advances in the study of SO2 effects on the catalytic oxidation of NO, HCs, and CO over DOCs, with particular attention to the fundamentals beneath apparent observations of sulfur influence on PGM-based and non-noble metal-based catalysts in the different oxidation reactions. Regeneration methods and design rationale for sulfur-resistant catalysts are also covered. Several challenges in the future research regarding microscopic insights into the SO2-influencing mechanism and next-generation sulfur-resistant DOC design are highlighted toward real-world practice.

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Section: Doc Working Architecture/functionalitiessupporting

confidence: 53%

Section: Doc Working Architecture/functionalitiesmentioning

confidence: 99%

A Review on the Impact of SO₂ on the Oxidation of NO, Hydrocarbons, and CO in Diesel Emission Control Catalysis

et al. 2021

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“…Platinum group metals (PGMs) are widely used as catalytically active phase in catalyst. Their unique electronic d-band structure allows them to be applied in many kinds of different reactions including CO oxidation, − methane oxidation, − hydrogenation, , and water–gas shift reaction. , PGMs should be well dispersed on supports to increase the cost-effectiveness (catalytic activity/amounts) because of their high price. When PGMs are dispersed on supports, PGM and support interact electronically with each other, which brings about the characteristic physiochemical effects on their catalytic properties .…”

Section: Introductionmentioning

confidence: 99%

How Pt Interacts with CeO₂ under the Reducing and Oxidizing Environments at Elevated Temperature: The Origin of Improved Thermal Stability of Pt/CeO₂ Compared to CeO₂

et al. 2016

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The interaction between Pt and CeO2 under reducing and oxidizing conditions as well as its effect on the thermal stability of Pt/CeO2 were extensively investigated by means of N2 adsorption/desorption, Raman spectroscopy, CO chemisorption, H2 TPR, XRD, and XPS techniques. In situ and ex situ Raman spectroscopy showed that Pt is anchored with the surface oxygen of CeO2 by forming Pt–O–Ce bond during the oxidative treatment of Pt/CeO2. Under the reducing condition, the static CO chemisorption presented that the amount of CO adsorbed on CeO2 is almost equal to that on Pt/CeO2, implying that Pt atom is located on the oxygen vacancy generated on reduced CeO2 surface. Strong Pt–O–Ce bond maintained the textural properties of Pt/CeO2 from oxidative treatment at temperature as high as 800 °C, as evidenced by the XRD patterns and BJH curves of the samples. Selective removal of the surface oxygen of Pt/CeO2 resulted in the decreased thermal stability of Pt/CeO2 due to the loss of Pt–O–Ce bond. Stronger interaction between Pt and CeO2 is observed when the oxidation temperature was increased from 500 to 800 °C, as evidenced by the shift of the surface reduction peak of Pt/CeO2 in H2 TPR to the higher temperature. It is consistent with in situ Raman spectra of Pt/CeO2, which showed that Pt–O–Ce bond became more resistant to the reduction by H2 after the oxidative treatment at 800 °C. Hence, it is concluded that Pt–O–Ce bond plays an important role in improving the thermal stability of Pt/CeO2 upon the oxidative treatment at high temperature. Based on characterization results, the model is proposed to explain the interaction between Pt and CeO2 under the oxidative treatment.

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“…Platinum group metals (PGMs) are known to be catalytically active in many reactions including hydrogenation, , water–gas-shift (WGS) reaction, − CO oxidation, − oxygen reduction reaction, and many others. − One of the primary concerns for the application of PGM catalysts lie in how to attain the high metal dispersion on the support because of the high cost and the scarcity of noble metals. It is well-known that the high PGM dispersion could be obtained when reducible metal oxides, such as ceria or titania, are used as a support, which leads to the strong metal–support interaction between PGMs and reducible metal oxide .…”

Section: Introductionmentioning

confidence: 99%

Influence of the Defect Concentration of Ceria on the Pt Dispersion and the CO Oxidation Activity of Pt/CeO₂

et al. 2018

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The CO oxidation ability can be modulated by controlling the metal− support interaction of Pt/CeO 2 catalysts. The Pt/(800C)CeO 2 sample prepared by the thermal treatment of ceria at 800 °C before loading Pt maintained the much higher Pt dispersion than Pt/γ-Al 2 O 3 after the thermal aging at 800 °C, indicating its excellent thermal resistance against Pt sintering. In addition, the CO oxidation rate of the Pt/ (800C)CeO 2 catalyst was order of magnitude higher than that of the Pt/CeO 2 catalyst. Such enhanced activity is explained by the weakened Pt−ceria interaction in Pt/ (800C)CeO 2 , which is evidenced by the formation of PtO 2 species that interact weakly with ceria rather than that of Pt−O−Ce species interacting strongly with ceria. The presence of PtO 2 species appears to be essential for the high CO oxidation ability.

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Roles of ZrO2 in SO2-poisoned Pd/(Ce-Zr)O2 catalysts for CO oxidation

Cited by 29 publications

References 54 publications

A Review on the Impact of SO₂ on the Oxidation of NO, Hydrocarbons, and CO in Diesel Emission Control Catalysis

A Review on the Impact of SO₂ on the Oxidation of NO, Hydrocarbons, and CO in Diesel Emission Control Catalysis

How Pt Interacts with CeO₂ under the Reducing and Oxidizing Environments at Elevated Temperature: The Origin of Improved Thermal Stability of Pt/CeO₂ Compared to CeO₂

Influence of the Defect Concentration of Ceria on the Pt Dispersion and the CO Oxidation Activity of Pt/CeO₂

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Roles of ZrO2 in SO2-poisoned Pd/(Ce-Zr)O2 catalysts for CO oxidation

Cited by 29 publications

References 54 publications

A Review on the Impact of SO2 on the Oxidation of NO, Hydrocarbons, and CO in Diesel Emission Control Catalysis

A Review on the Impact of SO2 on the Oxidation of NO, Hydrocarbons, and CO in Diesel Emission Control Catalysis

How Pt Interacts with CeO2 under the Reducing and Oxidizing Environments at Elevated Temperature: The Origin of Improved Thermal Stability of Pt/CeO2 Compared to CeO2

Influence of the Defect Concentration of Ceria on the Pt Dispersion and the CO Oxidation Activity of Pt/CeO2

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A Review on the Impact of SO₂ on the Oxidation of NO, Hydrocarbons, and CO in Diesel Emission Control Catalysis

A Review on the Impact of SO₂ on the Oxidation of NO, Hydrocarbons, and CO in Diesel Emission Control Catalysis

How Pt Interacts with CeO₂ under the Reducing and Oxidizing Environments at Elevated Temperature: The Origin of Improved Thermal Stability of Pt/CeO₂ Compared to CeO₂

Influence of the Defect Concentration of Ceria on the Pt Dispersion and the CO Oxidation Activity of Pt/CeO₂