FTIR and density functional study of NO interaction with reduced ceria: Identification of N3− and NO2− as new intermediates in NO conversion

Mihaylov, Mihail; Ivanova, Elena; Aleksandrov, Hristiyan A.; Petkov, Petko St.; Vayssilov, Georgi N.; Hadjiivanov, Konstantin

doi:10.1016/j.apcatb.2015.03.054

Cited by 48 publications

(37 citation statements)

References 75 publications

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“…2124 cm −1 , and this band can be associated with the presence of oxygen vacancies. 52,53 The spectra presented in Figure 3 [inset, spectra (c,e)] clearly indicate the existence of Ce 3+ species on the reduced Pt/Ce/Al and Pt/Ce−Zr/Al samples.…”

Section: Articlementioning

confidence: 98%

Pt/CeO_x/ZrO_x/γ-Al₂O₃ Ternary Mixed Oxide DeNO_x Catalyst: Surface Chemistry and NO_x Interactions

Andonova

Drenchеv

et al. 2018

J. Phys. Chem. C

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Surface chemistry and the nature of the adsorbed NO x species on a Pt/CeO 2 −ZrO 2 /Al 2 O 3 catalyst were investigated by IR spectroscopy, X-ray diffraction, H 2temperature programmed reduction, and NO x-temperature programmed desorption. Parallel studies were also carried out with benchmark samples such as CeO 2 /Al 2 O 3 , ZrO 2 /Al 2 O 3 , CeO 2 −ZrO 2 /Al 2 O 3 and Pt-supported versions of these materials. All samples were studied in their reduced and nonreduced forms. The use of CO as a probe molecule revealed that during the synthesis of the mixed-metal oxide systems, deposited zirconia preferentially interacted with the alumina hydroxyls, while deposited ceria was preferentially located at the Lewis acid sites. Despite the limited extent of Zr 4+ ions incorporated into the CeO 2 lattice, the reduction of ceria was promoted and occurred at lower temperatures in the presence of zirconia. When deposited on ZrO 2 /Al 2 O 3 , platinum formed relatively big particles and existed in metallic state even in the nonreduced samples. The presence of ceria hindered platinum reduction during calcination and yielded a high platinum dispersion. Subsequent reduction with H 2 led to the production of metallic Pt particles. Consequently, NO adsorption on nonreduced Pt-containing materials was negligible but was enhanced on the reduced samples because of Pt 0-promoted NO disproportionation. The nature of the nitrogen-oxo species produced after NO and O 2 coadsorption on different samples was similar. Despite the high thermal stability of the NO x adsorbed species on the ceria and zirconia adsorption sites, the NO x reduction in the presence of H 2 was much more facile over Pt/CeO 2 −ZrO 2 /Al 2 O 3. Thus, the main differences in the NO x reduction functionalities of the investigated materials could be related to the ability of the catalysts to activate hydrogen at relatively lower temperatures.

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Section: Articlementioning

confidence: 98%

Pt/CeO_x/ZrO_x/γ-Al₂O₃ Ternary Mixed Oxide DeNO_x Catalyst: Surface Chemistry and NO_x Interactions

Andonova

Drenchеv

et al. 2018

J. Phys. Chem. C

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“…This position is characterized by the lowest absolute value of BE(CO), -1.92 eV, while the adsorption complexes on the other two positions are by ~0.2 eV more stable. The C-O vibrational frequency for the terrace site is 2065 cm CO adsorption on Pt 8 /Ce 21 Figure 3, Table 2). The oxygen atoms were removed from the positions found to be the most preferable ones for the bare Ce 21 The modeled structures are shown on Figure 4 and the obtained results are summarized in .…”

Section: Co Adsorption On Unsupported Platinum Modelsmentioning

confidence: 99%

“…The C-O vibrational frequency for the terrace site is 2065 cm CO adsorption on Pt 8 /Ce 21 Figure 3, Table 2). The oxygen atoms were removed from the positions found to be the most preferable ones for the bare Ce 21 The modeled structures are shown on Figure 4 and the obtained results are summarized in . The adsorption of the second CO molecule (in the structure ereg/(CO) 2 ) further stabilizes the complex increasing the value of BE per CO molecule to -1.04 eV (Fig.…”

Section: Co Adsorption On Unsupported Platinum Modelsmentioning

confidence: 99%

“…The process is reversible upon reactions with oxygen 18,19 or other oxidizing species. 20,21 Numerous experimental studies of Pt/CeO 2 systems used IR spectroscopy of adsorbed CO for clarification of the state of platinum species (Table 1) and their catalytic performance. 4,[22][23][24][25][26][27][28][29][30] For instance, Happel et al 22 have detected in IR spectra several vibrational bands when CO was adsorbed on ceria supported platinum nanoparticles ( Table 1).…”

Section: Introductionmentioning

confidence: 99%

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Can the state of platinum species be unambiguously determined by the stretching frequency of an adsorbed CO probe molecule?

Aleksandrov

Neyman

Hadjiivanov

et al. 2016

Phys. Chem. Chem. Phys.

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136

128

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Electronic Supplementary Information (ESI) available: Information includes sketches of all modeled Pt8(CO) complexes in gas phase and some of their energetic and structural characteristics, structure of e-reg/(CO)2 complex, and figure with the changes of the CO stretching frequency versus oxidation state and Bader charge of mononuclear platinum species. See DOI: 10.1039/x0xx00000x The paper addresses possible ambiguities in determination of the state of platinum species by the stretching frequency of a CO probe, which is a common technique for characterization of platinum-containing catalytic systems. We present a comprehensive comparison of the available experimental data with our theoretical modeling (density functional) results of pertinent systems -platinum surface, nanoparticles and clusters as well as reduced or oxidized platinum moieties on ceria support. Our results for CO adsorbed on-top on metallic Pt . This trend corroborates the Kappers-van der Maas correlation derived from analysis of experimental stretching frequency of CO adsorbed on platinum-containing samples on different supports. We also analyzed the effect of the charge of platinum species on the CO frequency. Based on the calculated vibrational frequencies of CO in various model systems, we concluded that the actual state of the platinum species may be mistaken based only on the measured value of the C-O vibrational frequency due to overlapping regions of frequencies corresponding to different types of species. In order to identify the actual state of platinum species one has to combine this powerful technique with other approaches.

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“…As shown in Fig. , the dominant absorption band of pure nitrite was at 1270.86 cm −1 , which belonged to the characteristic peak of N=O group (Mihaylov et al ., ). The same characteristic peak was found in casein solution with nitrite added at 0 h. However, after 24‐h cultivation, this absorption peak of N=O vanished completely.…”

Section: Resultsmentioning

confidence: 97%

Characterisation of dominant autochthonous strains for nitrite degradation of Chinese traditional fermented fish

Liao

Jiang

et al. 2018

Int J of Food Sci Tech

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Summary In this study, three previously isolated dominant autochthonous strains from Chinese traditional fermented fish products (CTFPs), namely Lactobacillus plantarum 120, Saccharomyces cerevisiae 2018 and Staphylococcus xylosus 135, were used to evaluate their nitrite degradation abilities. The highest nitrite degradation rate (NDR) was observed in L. plantarum 120 (90.70%), followed by S. cerevisiae 2018 (78.75%) and S. xylosus 135 (13.09%). The nitrite reductase activities of L. plantarum 120 and S. cerevisiae 2018 could be promoted by appropriate sodium chloride contents (4%–6%). Meanwhile, nitrite could be degraded in soluble grass carp proteins, and the NDR was positively associated with the protein concentration. Inoculation with L. plantarum 120, S. cerevisiae 2018 and S. xylosus 135 significantly (P < 0.05) decreased the nitrite and nitrate concentrations in CTFPs. Therefore, dominant autochthonous strains, especially L. plantarum 120 and S. cerevisiae 2018, could be used as promising starter cultures to inhibit nitrite accumulation in CTFPs.

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FTIR and density functional study of NO interaction with reduced ceria: Identification of N3− and NO2− as new intermediates in NO conversion

Cited by 48 publications

References 75 publications

Pt/CeO_x/ZrO_x/γ-Al₂O₃ Ternary Mixed Oxide DeNO_x Catalyst: Surface Chemistry and NO_x Interactions

Pt/CeO_x/ZrO_x/γ-Al₂O₃ Ternary Mixed Oxide DeNO_x Catalyst: Surface Chemistry and NO_x Interactions

Can the state of platinum species be unambiguously determined by the stretching frequency of an adsorbed CO probe molecule?

Characterisation of dominant autochthonous strains for nitrite degradation of Chinese traditional fermented fish

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FTIR and density functional study of NO interaction with reduced ceria: Identification of N3− and NO2− as new intermediates in NO conversion

Cited by 48 publications

References 75 publications

Pt/CeOx/ZrOx/γ-Al2O3 Ternary Mixed Oxide DeNOx Catalyst: Surface Chemistry and NOx Interactions

Pt/CeOx/ZrOx/γ-Al2O3 Ternary Mixed Oxide DeNOx Catalyst: Surface Chemistry and NOx Interactions

Can the state of platinum species be unambiguously determined by the stretching frequency of an adsorbed CO probe molecule?

Characterisation of dominant autochthonous strains for nitrite degradation of Chinese traditional fermented fish

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Pt/CeO_x/ZrO_x/γ-Al₂O₃ Ternary Mixed Oxide DeNO_x Catalyst: Surface Chemistry and NO_x Interactions

Pt/CeO_x/ZrO_x/γ-Al₂O₃ Ternary Mixed Oxide DeNO_x Catalyst: Surface Chemistry and NO_x Interactions