Reduction behavior and catalytic properties of cobalt containing ZSM-5 zeolites

Jong, Sung-Jeng; Cheng, Sheng-Tzong

doi:10.1016/0926-860x(95)00016-x

Cited by 81 publications

(27 citation statements)

References 15 publications

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“…H 2 -TPR ( Fig. 2) revealed the main reduction peaks at temperatures lower than 400 °C which are ascribed to the reduction of Co 3 O 4 that proceeds via a multistep mechanism (reduction of Co 3 O 4 to CoO and then to metallic Co) [29,30].…”

Section: Catalyst Characterizationmentioning

confidence: 99%

“…It has also been found that the Co 2+ cations in ZSM-5 cannot be altered in oxidation states upon oxygen and hydrogen treatment below 450 °C [42] and thus, given the relatively low temperature and short time on stream, cobalt ions inside the zeolite framework are difficult to be altered. In this case the framework of zeolites can function as a huge ligand to coordinate and stabilize its cations, preventing the latter from oxidation or reduction [29,42].…”

Section: Product Yields and Compositionmentioning

confidence: 99%

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Engineering the Catalytic Properties of HZSM5 by Cobalt Modification and Post-synthetic Hierarchical Porosity Development

et al. 2019

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Hierarchical zeolites have been identified as special catalytic materials with improved catalytic properties. In this study, hierarchical bifunctional ZSM5 based catalysts were prepared by desilication for controlled mesoporosity development and have been modified by Co doping. Their performance in the catalytic pyrolysis of oak in a lab scale reactor was evaluated. Desilicated counterparts were proven more active in deoxygenation of bio oil, while carbon deposition on the catalysts reduced compared to non-desilicated counterparts. Increased Lewis acidity favors decarboxylation reactions, while higher olefins as well as PAH content indicate easier diffusion within and from the porous network and interactions in the mesopores. The conversion of bulky lignin molecules (alkoxy phenols) is enhanced by the mesopores, while acidity is of secondary importance. Coke deposition inside the pores is more profound in the desilicated catalysts due to larger pore size. Carbon deposition on the catalysts is reduced in the following order: HZSM5 > Co/HZSM5 > Ds-HZSM5 > Co/Ds-HZSM5. GC-MS characterization of the CH 2 Cl 2 soluble coke indicated that for the desilicated counterparts the main coke precursors are the bulky lignin molecules which are partially deoxygenated.

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Section: Catalyst Characterizationmentioning

confidence: 99%

Section: Product Yields and Compositionmentioning

confidence: 99%

Engineering the Catalytic Properties of HZSM5 by Cobalt Modification and Post-synthetic Hierarchical Porosity Development

et al. 2019

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“…These results are also consistent with the XRD measurement. Most Co species exist in the form of Co 2+ at the ion exchange sites and the further reduction of Co 2+ into Co 0 occurred above 1000 °C [31]. As seen from Fig.…”

Section: Catalytic Activitymentioning

confidence: 72%

Influence of co-fed gases (O2, CO2, CH4, and H2O) on the N2O decomposition over (Co, Fe)-ZSM-5 and (Co, Fe)-BETA catalysts

Biturini

Santos

Batista

2018

Reac Kinet Mech Cat

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The influence of co-fed gases (O 2 , CO 2 , CH 4 , and H 2 O) on the N 2 O decomposition over (Co or Fe)-BETA and (Co, Fe)-ZSM-5 catalysts prepared by ion exchange method was investigated. Co 2+ ions and oxo dinuclear Co species were identified in Co-ZSM-5 and Co-BETA catalysts. Isolated and oligomeric Fe 3+ species in cationic sites and Fe 2 O 3 particles were found on surface of the Fe-ZSM-5 and Fe-BETA catalysts. Cobalt catalysts were more actives than iron catalysts for the direct decomposition of N 2 O. Conversion of N 2 O over Fe-BETA and Fe-ZSM-5 was remained stable when co-fed O 2 , CO 2 , and CH 4 , but decreases with water vapor. However, Co-BETA and Co-ZSM-5 showed much larger reaction rate for N 2 O decomposition and were very stable when co-fed O 2 , CO 2 , CH 4 , and especially H 2 O. The results showed that the higher CH 4 consumption during N 2 O reaction over Co-BETA and Co-ZSM-5 was due to CH 4 combustion. Keywords N 2 O decomposition • Co-fed gases • Iron species • Cobalt species • ZSM-5 zeolite • BETA zeolite

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“…The phyllosilicate phase, though evoked by Jong and Cheng [22] also on Co 2þ /ZSM5, is evidenced here for the first time for the preparation of a Co 2þ /zeolite system. This reveals the limits of the detection of extraframework phases based on the interpretation of TPR results only: high quantities of cobalt can be ultimately retained on catalyst SEA, though neither in the form of isolated ions nor oxide particles.…”

Section: Mechanism Of Formation Of the Phyllosilicate Phasementioning

confidence: 85%

Formation of Cobalt Phyllosilicate During Solid State Preparation of Co2+/ZSM5 Catalysts from Cobalt Acetate

et al. 2004

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Reduction behavior and catalytic properties of cobalt containing ZSM-5 zeolites

Cited by 81 publications

References 15 publications

Engineering the Catalytic Properties of HZSM5 by Cobalt Modification and Post-synthetic Hierarchical Porosity Development

Engineering the Catalytic Properties of HZSM5 by Cobalt Modification and Post-synthetic Hierarchical Porosity Development

Influence of co-fed gases (O2, CO2, CH4, and H2O) on the N2O decomposition over (Co, Fe)-ZSM-5 and (Co, Fe)-BETA catalysts

Formation of Cobalt Phyllosilicate During Solid State Preparation of Co2+/ZSM5 Catalysts from Cobalt Acetate

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