Alkali and earth alkali modified CuOx/SiO2 catalysts for propylene partial oxidation: What determines the selectivity?

Teržan, Janvit; Djinović, Petar; Zavašnik, Janez; Arčon, Iztok; Žerjav, Gregor; Spreitzer, Matjaž; Pintar, Albin

doi:10.1016/j.apcatb.2018.05.092

Cited by 37 publications

(42 citation statements)

References 40 publications

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“…The valence state of Cu cation can be determined from the energy position of the Cu K‐edge. The changes in energy (about 4 eV) of the Cu K‐edge is observed between Cu + and Cu 2+ cations, while a smaller edge shift of about 1 eV is exhibited between metallic Cu 0 and Cu + cation [32–36] . The energy position of Cu K‐edge in all Cu modified CeO 2 catalysts with different CeO 2 morphologies and with different Cu loadings in the initial state at room temperature coincides with the energy position of Cu 2+ reference compounds (Figure S3), so we can conclude that Cu cations in the catalysts at room temperature are in divalent form.…”

Section: Resultssupporting

confidence: 54%

In‐situ XAS Study of Catalytic N₂O Decomposition Over CuO/CeO₂ Catalysts

et al. 2021

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We performed in‐situ XAS study of N2O decomposition over CuO/CeO2 catalysts. The Cu K‐edge and Ce L3‐edge XANES and EXAFS analyses revealed the dynamic and crucial role of Cu2+/Cu+ and Ce4+/Ce3+ ionic pairs during the catalytic reaction. We observed the initial formation of reduced Cu+ and Ce3+ species during activation in helium atmosphere at 400 °C, while concentration of these species decreased significantly during steady‐state nitrous oxide degradation reaction (2500 ppm N2O in He at 400 °C). In‐situ EXAFS analysis further revealed a crucial role of copper−ceria interface in this catalytic reaction. We observed dynamic changes in average number of Cu−Ce scatters under reaction conditions, indicating an enlarging of the interface between both copper and ceria phases, where electron and oxygen transfer occurs.

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Section: Resultssupporting

confidence: 54%

In‐situ XAS Study of Catalytic N₂O Decomposition Over CuO/CeO₂ Catalysts

et al. 2021

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“…K improves the oxidation selectivity by reducing the reactivity of lattice oxygen on Fe-based catalysts in propylene epoxidation [202] and reduces the by-product acetaldehyde production on the Co-Mn-Al catalyst in ethanol oxidation [203]. For the propylene partial oxidation over CuO x /SiO 2 catalysts, K decreases the nucleophilic strength of oxygen in CuO x by attracting its electrons, accompanied by a notable shift in selectivity from acrolein towards propylene oxide, as shown in Figure 15 [16].…”

Section: Promotion Effects Of K On Reaction Processmentioning

confidence: 95%

“…Partial oxidation of VOCs and reforming of VOCs are the important ways to produce chemical raw materials. For example, partially oxidizing VOCs will produce cyclopropane and hydrogen [16,17]. The CO 2 reforming of methane is considered the most popular way to produce syngas [18].…”

Section: Componentsmentioning

confidence: 99%

Application Prospect of K Used for Catalytic Removal of NOx, COx, and VOCs from Industrial Flue Gas: A Review

Shi

et al. 2021

Catalysts

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NOx, COx, and volatile organic compounds (VOCs) widely exist in motor vehicle exhaust, coke oven flue gas, sintering flue gas, and pelletizing flue gas. Potassium species have an excellent promotion effect on various catalytic reactions for the treatment of these pollutants. This work reviews the promotion effects of potassium species on the reaction processes, including adsorption, desorption, the pathway and selectivity of reaction, recovery of active center, and effects on the properties of catalysts, including basicity, electron donor characteristics, redox property, active center, stability, and strong metal-to support interaction. The suggestions about how to improve the promotion effects of potassium species in various catalytic reactions are put forward, which involve controlling carriers, content, preparation methods and reaction conditions. The promotion effects of different alkali metals are also compared. The article number about commonly used active metals and promotion ways are also analyzed by bibliometric on NOx, COx, and VOCs. The promotion mechanism of potassium species on various reactions is similar; therefore, the application prospect of potassium species for the coupling control of multi-pollutants in industrial flue gas at low-temperature is described.

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“…In the Cu/ZSM-5 sample's spectra, the strong band at about 230 nm is assigned to the d − d transition of the chargetransfer band, which relates to the transition O ⟶ Cu from lattice oxygen to isolated Cu 2+ ions [6]. In addition, the broad but less intense band between 650 and 850 nm in Cu/ ZSM-5 and Cu-Fe/ZSM-5 relates to the d − d transition of Cu 2+ ions in an octahedral environment due to the distributed CuO particles [42]. With the Fe species, the band below 300 nm confirms the existence of isolated iron ions in the structure of tetrahedrons or octahedrons.…”

Section: Cu and Fe Species Onto Zsm-5mentioning

confidence: 99%

Hybrid Cu-Fe/ZSM-5 Catalyst Prepared by Liquid Ion-Exchange for NOx Removal by NH3-SCR Process

Doan

Dang

Nguyen

et al. 2021

Journal of Chemistry

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A series of Cu/ZSM-5, Fe/ZSM-5, and Cu-Fe/ZSM-5 catalysts (Si/Al in ZSM-5 = 25) were prepared by different metal loadings using the liquid ion-exchange method. Several characterization methods were conducted to explore the effects of metals on the physical and chemical properties of catalysts. Meanwhile, the electron paramagnetic resonance method is also used to assess the copper and/or iron elements’ coordination and valence state at intersections or in channels of ZSM-5. The metal-loading effects of all catalysts on the catalytic activities were studied for the removal of NOx in a fixed-bed flow reactor using selective catalytic reduction with ammonia (NH3-SCR). The results showed that the iron’s addition could markedly broaden the operation temperature range of the Cu/ZSM-5 catalyst for NH3-SCR between 200 and 550°C due to the presence of more isolated Cu2+ ions as well as additional oligomeric Fe3+ active sites and FexOy oligomeric species. This paper gives a facile and straightforward way to synthesize the practical-promising catalyst applied in NH3-SCR technology to control NOx emissions.

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Alkali and earth alkali modified CuOx/SiO2 catalysts for propylene partial oxidation: What determines the selectivity?

Cited by 37 publications

References 40 publications

In‐situ XAS Study of Catalytic N₂O Decomposition Over CuO/CeO₂ Catalysts

In‐situ XAS Study of Catalytic N₂O Decomposition Over CuO/CeO₂ Catalysts

Application Prospect of K Used for Catalytic Removal of NOx, COx, and VOCs from Industrial Flue Gas: A Review

Hybrid Cu-Fe/ZSM-5 Catalyst Prepared by Liquid Ion-Exchange for NOx Removal by NH3-SCR Process

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Alkali and earth alkali modified CuOx/SiO2 catalysts for propylene partial oxidation: What determines the selectivity?

Cited by 37 publications

References 40 publications

In‐situ XAS Study of Catalytic N2O Decomposition Over CuO/CeO2 Catalysts

In‐situ XAS Study of Catalytic N2O Decomposition Over CuO/CeO2 Catalysts

Application Prospect of K Used for Catalytic Removal of NOx, COx, and VOCs from Industrial Flue Gas: A Review

Hybrid Cu-Fe/ZSM-5 Catalyst Prepared by Liquid Ion-Exchange for NOx Removal by NH3-SCR Process

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Product

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In‐situ XAS Study of Catalytic N₂O Decomposition Over CuO/CeO₂ Catalysts

In‐situ XAS Study of Catalytic N₂O Decomposition Over CuO/CeO₂ Catalysts