Ethane Aromatization over Zn-HZSM-5: Early-Stage Acidity/Performance Relationships and Deactivation Kinetics

Liang, Tian; Fadaeerayeni, Siavash; Shan, Junjun; Li, Tao; Wang, Hui; Cheng, Jiansong; Toghiani, Hossein; Xiang, Yizhi

doi:10.1021/acs.iecr.9b03012

Cited by 28 publications

(22 citation statements)

References 41 publications

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“…The acid properties of the 0.5 wt % Pt/HZSM-5 (SAR = 15) catalyst were characterized by NH 3 - and C 3 H 7 NH 2 -temperature-programmed desorption (TPD). The detailed experiment procedures can be found in our previous study . The size of Pt particles on HZSM-5 was characterized by transmission electron microscopy (TEM) using a JEOL 2100TEM (accelerating voltage 200 kV) equipped with Gatan camera.…”

Section: Methodsmentioning

confidence: 99%

Catalytic Light Alkanes Conversion through Anaerobic Ammodehydrogenation

et al. 2021

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Catalytic transformation of light alkanes could have considerable practical value, yet remains one of the most challenging areas in catalysis research due to the inertness of the C–H bond. Here, we proposed an efficient ammodehydrogenation (ADeH) catalytic system for the direct C–N linkage between light alkanes and ammonia for CH3CN and H2 (CO x free) production. This breakthrough is achieved over bifunctional metal-modified HZSM-5 catalysts, through the tandem dehydrogenation–amination–dehydrogenation mechanism. We show that ethane ADeH over the Pt/HZSM-5 catalyst can be realized under atmospheric pressure at temperatures as low as 350 °C. The specific rate of CH3CN is ∼60 μmol/(g min), and the selectivity is up to 99% under such mild conditions. The yield of CH3CN increases with increasing temperature; however, the selectivity decreases due to the formation of HCN, C2H4, and CH4. Additionally, the Pt/HZSM-5 catalyst is coke-resistant during the ADeH owing to the strong interaction between NH3 and the acid sites of the catalyst. We anticipate that the proposed ADeH could be extended for the transformation of various n/iso-alkanes with tunable selectivity to alkene and nitriles.

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Section: Methodsmentioning

confidence: 99%

Catalytic Light Alkanes Conversion through Anaerobic Ammodehydrogenation

et al. 2021

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“…− tetrahedral structure in the zeolites [32][33][34][35]. When the Si/Al ratio of a zeolite is fixed, there should be an optimal Cu loading in Cu/zeolite catalysts, which can not only ensure the formation of enough active Cu species to guarantee high NH 3 -SCR activity, but also stabilize the zeolite framework, thereby improving the hydrothermal stability of catalysts [36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Catalytic Performances of Cu/MCM-22 Zeolites with Different Cu Loadings in NH3-SCR

et al. 2020

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The NH3-SCR activities and hydrothermal stabilities of five xCu/MCM-22 zeolites with different Cu loadings (x = 2–10 wt%) prepared by incipient wetness impregnation method were systematically investigated. The physicochemical properties of xCu/MCM-22 zeolites were analyzed by XRD, nitrogen physisorption, ICP-AES, SEM, NH3-TPD, UV-vis, H2-TPR and XPS experiments. The Cu species existing in xCu/MCM-22 are mainly isolated Cu2+, CuOx and unreducible copper species. The concentrations of both isolated Cu2+ and CuOx species in xCu/MCM-22 increase with Cu contents, but the increment of CuOx species is more distinct, especially in high Cu loadings (>4 wt%). NH3-SCR experimental results demonstrated that the activity of xCu/MCM-22 is sensitive to Cu content at low Cu loadings (≤4 wt%). When the Cu loading exceeds 4 wt%, the NH3-SCR activity of xCu/MCM-22 is irrelevant to Cu content due to the severe pore blockage effects caused by aggregated CuOx species. Among the five xCu/MCM-22 zeolites, 4Cu/MCM-22 with moderate Cu content has the best NH3-SCR performance, which displays higher than 80% NOx conversions in a wide temperature window (160–430 °C). Furthermore, the hydrothermal aging experiments (xCu/MCM-22 was treated at 750 °C for 10 h under 10% water vapor atmosphere) illustrated that all the xCu/MCM-22 zeolites exhibit high hydrothermal stability in NH3-SCR reactions.

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“…This can be understood from the relative increase in aromatization function upon Gallium addition. Dehydrogenation is one of the important step in aromatization and deep dehydrogenation of intermediate species may lead to more coking [41] …”

Section: Resultsmentioning

confidence: 99%

“…Dehydrogenation is one of the important step in aromatization and deep dehydrogenation of intermediate species may lead to more coking. [41] Catalytic evaluation…”

Section: Nh 3 -Tpd and Coke Formationmentioning

confidence: 99%

Aromatization of Commercial Full Range Naphtha Over Modified Hierarchical ZSM‐5 Catalyst

et al. 2021

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Aromatization of commercial full range naphtha has been studied in a fixed bed reactor using the synthesized hierarchical zeolite catalysts. Desilication was carried out on H‐ZSM‐5 support with Silica to Alumina (SiO2/Al2O3) molar ratio 30 to generate additional meso‐porosity and active metal Gallium was incorporated by wetness impregnation method. Various concentrations of sodium hydroxide solutions and two different initial calcination temperature were used during the modification to understand the effect of these parameters on the catalysts. All the catalysts were characterized using nitrogen adsorption, X‐ray diffraction, temperature programmed ammonia desorption, elemental and surface imaging techniques. Catalytic evaluation is done in a fixed bed reactor operated at a temperature of 550 °C, atmospheric pressure and liquid hourly space velocity of 6.0 h−1. Product streams from the fixed bed reactor are analyzed using both online and offline gas chromatographs using ASTM D7833 and D6729 respectively to report product selectivity and mass balance. It is observed that the additional meso porosity and the retention of crystallite phase lead to 62.4 % enhancement in aromatic selectivity and 52.2 % decrease in off‐gas generation for the developed catalyst compared to its non‐desilicated analogue during the aromatization process of full range real naphtha.

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Ethane Aromatization over Zn-HZSM-5: Early-Stage Acidity/Performance Relationships and Deactivation Kinetics

Cited by 28 publications

References 41 publications

Catalytic Light Alkanes Conversion through Anaerobic Ammodehydrogenation

Catalytic Light Alkanes Conversion through Anaerobic Ammodehydrogenation

Catalytic Performances of Cu/MCM-22 Zeolites with Different Cu Loadings in NH3-SCR

Aromatization of Commercial Full Range Naphtha Over Modified Hierarchical ZSM‐5 Catalyst

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