Comparison of Pt-BaO/Al2O3 and Pt-CeO2/Al2O3 for NOx storage and reduction: Impact of cycling frequency

Zhou, Zhiyu; Harold, Michael P.; Luss, Dan

doi:10.1016/j.apcatb.2019.05.044

Cited by 23 publications

(9 citation statements)

References 62 publications

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“…The NO uptake at 100 °C reveals that additional NO is trapped by the OC, an amount determined to be ∼12 μmoles (Table ). It is known from the NSR literature that NO/NO 2 adsorbs on CeO 2 as nitrites and/or nitrates below 200 °C. ,,− Vacancies in the fluorite crystal structure of ceria provide sites for NO adsorption. Utilizing Raman spectroscopy, Filtschew and Hess proposed that adsorption of NO and NO 2 occurs, forming nitrates and nitrites, as given by reactions –.…”

Section: Resultsmentioning

confidence: 99%

NO_x and Hydrocarbon Trapping and Conversion in a Sequential Three-Zone Monolith: Spatiotemporal Features

2022

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The spatiotemporal features of the multifunctional monolithic lean hydrocarbon NO x trap (LHCNT), for eliminating NO x (x = 1 and 2) and ethylene (C 2 H 4 ), are examined using spatially resolved mass spectrometry (SpaciMS), spanning the sequentially positioned passive NO x adsorber (PNA; Pd/SSZ-13), hydrocarbon trap (HCT; Pd/BEA), and oxidation catalyst (OC; Pt/Al 2 O 3 −CeO 2 ). The overall LHCNT performance is captured in temporal trapping efficiency profiles, which show the integral NO and C 2 H 4 uptake followed by delayed NO release along with NO and ethylene oxidation. Spatially resolved transient concentration profiles spanning uptake, release, and conversion of NO, H 2 , and C 2 H 4 , alone or as mixtures in feeds containing H 2 O, provide detailed insight into the transient coupling not attainable with effluent concentration monitoring alone. The PNA serves as the primary zone for NO uptake, followed by the OC and HCT. NO oxidation to NO 2 occurs during NO uptake in the PNA due to Pd(II) reduction, while more extensive oxidation occurs in the OC at higher temperature. C 2 H 4 uptake and oxidation occur in each of the functions with oxidation occurring the earliest (lowest temperature) in the OC. NO uptake in the PNA and HCT is negligibly affected by H 2 but protracted oxidation of H 2 during the temperature ramp delays NO release, suggesting persistence of NO bound on Pd(I). Both the PNA and HCT exhibit excellent C 2 H 4 uptake, which diminishes in the presence of NO. Spatially resolved concentration data reveal several interesting features, such as high-temperature, sequential NO oxidation (by O 2 to NO 2 ) and C 2 H 4 oxidation (by NO 2 to NO + CO 2 ) in the PNA. Simulated warmup experiments reveal that the LHCNT NO trapping is enhanced with C 2 H 4 addition but that a reduction in space velocity may be needed to improve performance. A previously developed PNA model predicts satisfactorily the main features of spatially resolved NO and NO + C 2 H 4 data.

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Section: Resultsmentioning

confidence: 99%

NO_x and Hydrocarbon Trapping and Conversion in a Sequential Three-Zone Monolith: Spatiotemporal Features

2022

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“…Although ceria addition did not appear to exert a substantial influence on the overall NO x storage capacity, it did have a clearly positive impact on NO x reduction. Zhou et al 150 examined the influence of NO x storage materials (CeO 2 and BaO) on NO x conversion and systematically compared the deNO x performances of Pt/Al 2 O 3 , Pt/CeO 2 /Al 2 O 3 , and Pt/BaO/Al 2 O 3 catalysts. Pt/CeO 2 /Al 2 O 3 and Pt/BaO/Al 2 O 3 exhibit the highest NO x conversion below and above 300 °C, respectively.…”

Section: Application Of Cerium-based Oxide Catalysts To Catalytic Eli...mentioning

confidence: 99%

Construction of cerium-based oxide catalysts with abundant defects/vacancies and their application to catalytic elimination of air pollutants

Gao,

Yu,

Zhou

et al. 2023

J. Mater. Chem. A

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“…Moreover, the electrified NSR over Pt−K/ATO also exhibits a lower T 50 (∼250 °C) than those for the reported thermal NSR over Pt−Ba/Al 2 O 3 (∼400 °C) and Pt-CeO 2 /Al 2 O 3 (∼500 °C) using C 3 H 6 as reductants as well. 7 In order to demonstrate vividly the relation of the NSR cycle to catalyst conductivity, the evolution of inlet and outlet gas concentrations and electric resistances (R) of the catalyst is described in detail under the fuel-lean/fuel-rich switching during the electrified NSR reaction at 4 W corresponding to the temperature of 280 °C at which the largest NO x conversion (63%) is obtained and thus the evolution profile is maximized (Figure 3c, and those at other powers are shown in Figure S6). Compared with the inlet C 3 H 6 and NO x concentrations, the outlet concentrations are greatly decreased.…”

Section: Performance Of Electrified Nsrmentioning

confidence: 99%

Electrification-Enhanced Low-Temperature NO_x Storage–Reduction on Pt and K Co-Supported Antimony-Doped Tin Oxides

Mei,

Xin,

Zhang

et al. 2023

Environ. Sci. Technol.

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Comparison of Pt-BaO/Al2O3 and Pt-CeO2/Al2O3 for NOx storage and reduction: Impact of cycling frequency

Cited by 23 publications

References 62 publications

NO_x and Hydrocarbon Trapping and Conversion in a Sequential Three-Zone Monolith: Spatiotemporal Features

NO_x and Hydrocarbon Trapping and Conversion in a Sequential Three-Zone Monolith: Spatiotemporal Features

Construction of cerium-based oxide catalysts with abundant defects/vacancies and their application to catalytic elimination of air pollutants

Electrification-Enhanced Low-Temperature NO_x Storage–Reduction on Pt and K Co-Supported Antimony-Doped Tin Oxides

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Comparison of Pt-BaO/Al2O3 and Pt-CeO2/Al2O3 for NOx storage and reduction: Impact of cycling frequency

Cited by 23 publications

References 62 publications

NOx and Hydrocarbon Trapping and Conversion in a Sequential Three-Zone Monolith: Spatiotemporal Features

NOx and Hydrocarbon Trapping and Conversion in a Sequential Three-Zone Monolith: Spatiotemporal Features

Construction of cerium-based oxide catalysts with abundant defects/vacancies and their application to catalytic elimination of air pollutants

Electrification-Enhanced Low-Temperature NOx Storage–Reduction on Pt and K Co-Supported Antimony-Doped Tin Oxides

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NO_x and Hydrocarbon Trapping and Conversion in a Sequential Three-Zone Monolith: Spatiotemporal Features

NO_x and Hydrocarbon Trapping and Conversion in a Sequential Three-Zone Monolith: Spatiotemporal Features

Electrification-Enhanced Low-Temperature NO_x Storage–Reduction on Pt and K Co-Supported Antimony-Doped Tin Oxides