A study on the roles of cobalt species in NOx reduction by propane on Co-Beta

Ohtsuka, Hirofumi; Tabata, Takeshi; Okada, Osamu; Sabatino, L.; Bellussi, Giuseppe

doi:10.1016/s0920-5861(98)00075-3

Cited by 59 publications

(29 citation statements)

References 13 publications

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“…In the same spectrum, a band at around 580 cm -1 is also observed. As this band can not be attributed to the zeolite framework nor to Co 3 O 4 , it is suggested that it corresponds to a loaded cobalt species other than Co 3 O 4 (e. g. CoO(OH)) 22 . Figure 7 shows the DRS-UV/VIS spectra of the |Cu x |[Si y Al]-MFI catalysts.…”

Section: Catalyst Characterisationmentioning

confidence: 94%

“…Figure 6 shows the spectra obtained from the |Co 0.58 |[Si 12 Al]-MFI catalyst, Co 3 O 4 (reference sample) and the zeolite used as precursor. As can be seen, the bands at 303 and 385 cm -1 in the spectrum of |Co 0.58 |[Si 12 Al]-MFI correspond to the zeolite framework and they are not related to the Co-species 22 . In addition, bands at 197, 483, 529, 616 and 692 cm -1 can be observed in the spectra.…”

Section: Catalyst Characterisationmentioning

confidence: 99%

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Cu and Co exchanged ZSM-5 zeolites: activity towards no reduction and hydrocarbon oxidation

et al. 2006

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(y = 12, 25 and 45). The activity of the catalysts was evaluated in the reduction of NO to N 2 in an oxidative atmosphere using propane or methane as reducing agents. The Cu catalysts were only active with propane and they presented higher activity than the Co-based catalysts, the latter being active with both hydrocarbons. H 2 -TPR and DRS-UV/Vis data allowed correlation between the activity towards NO reduction and the presence of cationic charge-compensating species in the zeolite. It was also verified that the hydrocarbons are preferentially oxidised by O 2 , a reaction that occurs simultaneously with their oxidation with NO.

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Section: Catalyst Characterisationmentioning

confidence: 94%

Section: Catalyst Characterisationmentioning

confidence: 99%

Cu and Co exchanged ZSM-5 zeolites: activity towards no reduction and hydrocarbon oxidation

et al. 2006

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“…However, the intensity of the ZSM-5 principal diffraction peaks decreased to a certain extent after the copper and cerium incorporation, probably owing to the higher absorption coefficient of metal compounds for X-ray radiation [26]. No diffraction peaks derived from metal or metal oxide clusters are observed for Cu-Z, CuCe1-Z, CuCe2-Z and CuCe3-Z, suggesting that the species are well dispersed as amorphous metal species, or aggregated into mini-crystals that are too small to be detected by XRD [27]. With increasing the cerium content to 2.0 wt.%, the peak of CeO2 are observed for CuCe4-Z (2θ=28.2º ， PDF= 34-0394), which is explained by the fact that the extra-framework cerium is prone to agglomerate into cerium oxides clusters.…”

Section: Structure and Morphologymentioning

confidence: 98%

Cerium doped copper/ZSM-5 catalysts used for the selective catalytic reduction of nitrogen oxide with ammonia

Dou

Wang

et al. 2015

Chemical Engineering Journal

124

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Abstract:The CuCe/ZSM-5 catalysts with different cerium loadings (0, 0.5, 1.0, 1.5 and 2.0 wt.%) was investigated to evaluate the correlation between structural characteristics and catalytic performance for the selective catalytic reduction (SCR) of NO by NH3. It was found that the addition of cerium increased copper dispersion and prevented its crystallization. According to the results of X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction by hydrogen (H2-TPR), copper species were enriched on the ZSM-5 grain surfaces and part of copper ions was incorporated into the cerium lattice. Addition of cerium improved the redox properties of the CuCe/ZSM-5 catalysts, owing to the higher valence of copper and mobility of lattice oxygen than those of Cu/ZSM-5 catalyst. Hence the introduction of * Corresponding author. Tel.: +86-22-60601278; Fax.: +86-22-60600320 E-mail address: haoqinglan@tust.edu.cn ** Corresponding author. Tel.: +822 2220 0441; fax: +822 2220 2299 (K. Hui)E -mail address: kshui@hanyang.ac.kr (K. Hui) 2 cerium in Cu/ZSM-5 improved significantly NO conversion. On the one hand, the cerium introduction into Cu-Z enhances their low-temperature activities. 95% NO conversion is reached around 197 ºC for Cu-Z while the corresponding temperature value decreases to 148 ºC for CuCe4-Z. On the other hand, the temperature range of efficient NO reduction (95%) also extends to higher temperature when the cerium are added to Cu/ZSM-5. Among the Cu-Ce/ZSM-5 catalysts tested, the CuCe4-Z sample exhibits the highest catalytic activity with the temperature range for 90% NO removal of 148-427 ºC.

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“…The Raman spectra are characterized by broad bands. The broadness of the bands is indicative of amorphicity [65]. Nevertheless, several broad peaks of high intensity are distinguished.…”

Section: Surface Film Identificationmentioning

confidence: 99%

Al-Co Alloys Prepared by Vacuum Arc Melting: Correlating Microstructure Evolution and Aqueous Corrosion Behavior with Co Content

Lekatou

Sfikas

Petsa

et al. 2016

Metals

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Hypereutectic Al-Co alloys of various Co contents (7-20 weight % (wt.%) Co) were prepared by vacuum arc melting, aiming at investigating the influence of the cobalt content on the microstructure and corrosion behavior. Quite uniform and directional microstructures were attained. The obtained microstructures depended on the Co content, ranging from fully eutectic growth (7 wt.% and 10 wt.% Co) to coarse primary Al 9 Co 2 predominance (20 wt.% Co). Co dissolution in Al far exceeded the negligible equilibrium solubility of Co in Al; however, it was hardly uniform. By increasing the cobalt content, the fraction and coarseness of Al 9 Co 2 , the content of Co dissolved in the Al matrix, and the hardness and porosity of the alloy increased. All alloys exhibited similar corrosion behavior in 3.5 wt.% NaCl with high resistance to localized corrosion. Al-7 wt.% Co showed slightly superior corrosion resistance than the other compositions in terms of relatively low corrosion rate, relatively low passivation current density and scarcity of stress corrosion cracking indications. All Al-Co compositions demonstrated substantially higher resistance to localized corrosion than commercially pure Al produced by casting, cold rolling and arc melting. A corrosion mechanism was formulated. Surface films were identified.

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A study on the roles of cobalt species in NOx reduction by propane on Co-Beta

Cited by 59 publications

References 13 publications

Cu and Co exchanged ZSM-5 zeolites: activity towards no reduction and hydrocarbon oxidation

Cu and Co exchanged ZSM-5 zeolites: activity towards no reduction and hydrocarbon oxidation

Cerium doped copper/ZSM-5 catalysts used for the selective catalytic reduction of nitrogen oxide with ammonia

Al-Co Alloys Prepared by Vacuum Arc Melting: Correlating Microstructure Evolution and Aqueous Corrosion Behavior with Co Content

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