NO reduction by CO over copper catalyst supported on mixed CeO2 and Fe2O3: Catalyst design and activity test

Cheng, Xingxing; Zhang, Xingyu; Su, Dexin; Wang, Zhiqiang; Chang, Jiang; Ma, Chunyuan

doi:10.1016/j.apcatb.2018.08.054

Cited by 205 publications

(120 citation statements)

References 52 publications

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“…The peaks at 465-469 • C (peak β) and 759 • C (peak δ) are attributed to the ceria surface oxygen and bulk oxygen reduction, respectively, while the peaks at~377-390 • C (peak α) and 581-599 • C (peak γ) are ascribed to the iron species reduction, namely Fe 2 O 3 → Fe 3 O 4 and Fe 3 O 4 → Fe 0 , respectively [40,44]. In particular, the two aforementioned peaks could be referring to dispersed and clustered Fe 2 O 3 , accordingly [64]. Interestingly, the high-temperature peak δ (759 • C) that corresponds to ceria bulk oxygen reduction remains unaffected by the addition of iron, which can be attributed to the preferred existence of iron at the outermost shell of the nanoparticles [50].…”

Section: Redox Properties (H 2 -Tpr)mentioning

confidence: 99%

Facet-Dependent Reactivity of Fe2O3/CeO2 Nanocomposites: Effect of Ceria Morphology on CO Oxidation

et al. 2019

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Ceria has been widely studied either as catalyst itself or support of various active phases in many catalytic reactions, due to its unique redox and surface properties in conjunction to its lower cost, compared to noble metal-based catalytic systems. The rational design of catalytic materials, through appropriate tailoring of the particles’ shape and size, in order to acquire highly efficient nanocatalysts, is of major significance. Iron is considered to be one of the cheapest transition metals while its interaction with ceria support and their shape-dependent catalytic activity has not been fully investigated. In this work, we report on ceria nanostructures morphological effects (cubes, polyhedra, rods) on the textural, structural, surface, redox properties and, consequently, on the CO oxidation performance of the iron-ceria mixed oxides (Fe2O3/CeO2). A full characterization study involving N2 adsorption at –196 °C, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), temperature programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS) was performed. The results clearly revealed the key role of support morphology on the physicochemical properties and the catalytic behavior of the iron-ceria binary system, with the rod-shaped sample exhibiting the highest catalytic performance, both in terms of conversion and specific activity, due to its improved reducibility and oxygen mobility, along with its abundance in Fe2+ species.

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Section: Redox Properties (H 2 -Tpr)mentioning

confidence: 99%

Facet-Dependent Reactivity of Fe2O3/CeO2 Nanocomposites: Effect of Ceria Morphology on CO Oxidation

et al. 2019

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“…Meanwhile, it could be noticed that there were no distinguishable reduction peaks corresponds to cerium species. According to previous research [43], the typical reduction peaks at around 450 °C and 740 °C could be associated with the surface Ce 4+ converting to Ce 3+ and the bulk Ce 4+ transforming to Ce 3+ , respectively. In this work, the reduction peaks of cerium species were very weak due to the low-quality content of cerium.…”

Section: H 2 -Temperature-programmed Reduction (H 2 -Tpr) Analysismentioning

confidence: 56%

Structure–Activity Relationship Study of Mn/Fe Ratio Effects on Mn−Fe−Ce−Ox/γ-Al2O3 Nanocatalyst for NO Oxidation and Fast SCR Reaction

et al. 2018

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A series of Mn−Fe−Ce−Ox/γ-Al2O3 nanocatalysts were synthesized with different Mn/Fe ratios for the catalytic oxidation of NO into NO2 and the catalytic elimination of NOx via fast selective catalytic reduction (SCR) reaction. The effects of Mn/Fe ratio on the physicochemical properties of the samples were analyzed by means of various techniques including N2 adsorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H2-temperature-programmed reduction (TPR), NH3-temperature-programmed desorption (TPD) and NO-TPD, meanwhile, their catalytic performance was also evaluated and compared. Multiple characterizations revealed that the catalytic performance was highly dependent on the phase composition. The Mn15Fe15−Ce/Al sample with the Mn/Fe molar ratio of 1.0 presented the optimal structure characteristic among all tested samples, with the largest surface area, increased active components distributions, the reduced crystallinity and diminished particle sizes. In the meantime, the ratios of Mn4+/Mnn+, Fe2+/Fen+ and Ce3+/Cen+ in Mn15Fe15−Ce/Al samples were improved, which could enhance the redox capacity and increase the quantity of chemisorbed oxygen and oxygen vacancy, thus facilitating NO oxidation into NO2 and eventually promoting the fast SCR reaction. In accord with the structure results, the Mn15Fe15−Ce/Al sample exhibited the highest NO oxidation rate of 64.2% at 350 °C and the broadest temperature window of 75–350 °C with the NOx conversion >90%. Based on the structure–activity relationship discussion, the catalytic mechanism over the Mn−Fe−Ce ternary components supported by γ-Al2O3 were proposed. Overall, it was believed that the optimization of Mn/Fe ratio in Mn−Fe−Ce/Al nanocatalyst was an extremely effective method to improve the structure–activity relationships for NO pre-oxidation and the fast SCR reaction.

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“…While the transformation from Mn 2 O 3 to MnO was apt to happen at higher reaction temperatures [34], well coinciding with the temperature value of R3 peak. For Ce-containing sample, the typical CeO x reduction process usually presented two separated peaks, the one of approximately [35]. Therefore, the fourth wide reduction peak (R4) in the Mn−Ce/TiO 2 nanocatalyst was related to the reduction processes of Mn 3 O 4 to MnO and CeO 2 s to Ce 2 O 3 s simultaneously, and the fifth peak (R5) at around 717 • C was potentially associated with the CeO 2 b reduction reaction.…”

Section: Reducibility Propertiesmentioning

confidence: 99%

“…340 peak. For Ce-containing sample, the typical CeOx reduction process usually presented two 341 separated peaks, the one of CeO2 s converting to Ce2O3 s on the catalyst surface occurred at about 450 342 °C, the other one of CeO2 b transforming to Ce2O3 b in the catalyst bulk came up at 730 °C 343approximately[35]. Therefore, the fourth wide reduction peak (R4) in the Mn−Ce/TiO2 nanocatalyst 344 was related to the reduction processes of Mn3O4 to MnO and CeO2 s to Ce2O3 s simultaneously, and the…”

mentioning

confidence: 99%

High-Efficiency Catalytic Conversion of NOx by the Synergy of Nanocatalyst and Plasma: Effect of Mn-Based Bimetallic Active Species

et al. 2019

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Three typical Mn-based bimetallic nanocatalysts of Mn−Fe/TiO2, Mn−Co/TiO2, Mn−Ce/TiO2 were synthesized via the hydrothermal method to reveal the synergistic effects of dielectric barrier discharge (DBD) plasma and bimetallic nanocatalysts on NOx catalytic conversion. The plasma-catalyst hybrid catalysis was investigated compared with the catalytic effects of plasma alone and nanocatalyst alone. During the catalytic process of catalyst alone, the catalytic activities of all tested catalysts were lower than 20% at ambient temperature. While in the plasma-catalyst hybrid catalytic process, NOx conversion significantly improved with discharge energy enlarging. The maximum NOx conversion of about 99.5% achieved over Mn−Ce/TiO2 under discharge energy of 15 W·h/m3 at ambient temperature. The reaction temperature had an inhibiting effect on plasma-catalyst hybrid catalysis. Among these three Mn-based bimetallic nanocatalysts, Mn−Ce/TiO2 displayed the optimal catalytic property with higher catalytic activity and superior selectivity in the plasma-catalyst hybrid catalytic process. Furthermore, the physicochemical properties of these three typical Mn-based bimetallic nanocatalysts were analyzed by N2 adsorption, Transmission Electron Microscope (TEM), X-ray diffraction (XRD), H2-temperature-programmed reduction (TPR), NH3-temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS). The multiple characterizations demonstrated that the plasma-catalyst hybrid catalytic performance was highly dependent on the phase compositions. Mn−Ce/TiO2 nanocatalyst presented the optimal structure characteristic among all tested samples, with the largest surface area, the minished particle sizes, the reduced crystallinity, and the increased active components distributions. In the meantime, the ratios of Mn4+/(Mn2+ + Mn3+ + Mn4+) in the Mn−Ce/TiO2 sample was the highest, which was beneficial to plasma-catalyst hybrid catalysis. Generally, it was verified that the plasma-catalyst hybrid catalytic process with the Mn-based bimetallic nanocatalysts was an effective approach for high-efficiency catalytic conversion of NOx, especially at ambient temperature.

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NO reduction by CO over copper catalyst supported on mixed CeO2 and Fe2O3: Catalyst design and activity test

Cited by 205 publications

References 52 publications

Facet-Dependent Reactivity of Fe2O3/CeO2 Nanocomposites: Effect of Ceria Morphology on CO Oxidation

Facet-Dependent Reactivity of Fe2O3/CeO2 Nanocomposites: Effect of Ceria Morphology on CO Oxidation

Structure–Activity Relationship Study of Mn/Fe Ratio Effects on Mn−Fe−Ce−Ox/γ-Al2O3 Nanocatalyst for NO Oxidation and Fast SCR Reaction

High-Efficiency Catalytic Conversion of NOx by the Synergy of Nanocatalyst and Plasma: Effect of Mn-Based Bimetallic Active Species

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