Ammoxidation of ethylene into acetonitrile over Co-Zeolites catalysts

Cobalt zeolites: Preparation, characterization and catalytic properties for N2O decomposition

“…It is reported that for pure Co 3 O 4 the NH 3 desorption peak is lower than 220 °C with a much smaller NH 3 desorption amount than the parent zeolites and the Co/zeolites 29. Therefore, the decrease of acidic sites probably reveals that the original acidic sites are greatly affected after cobalt loading, which is consistent with the literatures reported28, 29 It is still not clear for us why Co‐loading leads to a strong NH 3 desorption peak at 590 °C, probably a result from synergic interactions between Co species and the support acid sites.…”

“…Therefore, the peak at low temperature region (300–400 °C) is assigned to the reduction of the external surface cobalt oxide in this work. The reduction peak at high temperature region in the Co‐based zeolite catalysts is mainly attributed to cobalt ions either in the phyllosilicate phase or deposited in the zeolite as monomeric or dimeric species 27–30. As for the obscure reduction peak of Co/ZSM‐5(25)‐3% and Co/Beta‐3% at high temperature (higher than 1000 °C), we think it is related to the collapse of the zeolite pore channels 31.…”

“…4A). The ammonia desorption peak at around 160 °C could be attributed to the physically adsorb NH 3 or NH 3 hydrogen bonded to weak acid sites such as silanol groups 28, 29, 35, 36. In contrast, the peak at 470 °C is normally related to decomposition of NH 4 + ions formed through NH 3 reacting with zeolite H + sites29, 36 that are related to framework/extra‐frame Al atom for the charge compensation 37.…”

Insights into the promotional roles of palladium in structure and performance of cobalt-based zeolite capsule catalyst for direct synthesis of C5–C11 iso-paraffins from syngas

“…It is clear to see that Co/Pd/SiO 2 /HZSM5-M had a similar activity to that of bare core catalyst Brønsted acid site density should be same in the two catalysts. However, during the hydrothermal synthesis of the capsule catalyst, some core catalyst could be etched and some cobalt ion might be trapped in the acidic zeolite, which could decrease the Brønsted acid site density of the capsule catalyst [52][53][54]. Therefore, a lower Brønsted acid site density should be obtained in the capsule catalyst.…”

Ultrasensitive hydrazine sensor fabrication based on Co-doped ZSM-5 zeolites for environmental safety

“…Cobalt-containing ZSM-5 zeolites have drawn a great deal of attention in recent years. They have been used as catalysts for a wide range of important chemical reactions, such as oxidation of styrene and a-pinene, 1,2 direct conversion of syngas to gasoline range hydrocarbons, 3 Fischer-Tropsch synthesis, 4 combustion of isopropanol, 5 oxidation of methane to methanol and formaldehyde 6,7 and ammoxidation of ethane 8 and ethylene. 9 High activity was reported for nitrogen oxides abatement over Co-ZSM-5 catalysts.…”