Dehydroaromatization of methane over Sn–Pt modified Mo/H-ZSM-5 zeolite catalysts: Effect of preparation method

Tshabalala, Themba E.; Coville, Neil J.; Anderson, James A.; Scurrell, Michael S.

doi:10.1016/j.apcata.2015.06.035

Cited by 23 publications

(10 citation statements)

References 71 publications

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“…At 973 K, addition of 0.1 wt % Sn to the Pt-Mo/H-ZSM-5 catalyst yielded slightly lower methane conversion while decreasing the extent of coke deposition and increasing the selectivity to aromatics. Catalysts prepared by sequential impregnation of Pt followed by Sn exhibited higher benzene selectivity and better coke mitigation in comparison to catalysts prepared by coimpregnation. , …”

Section: Introductionmentioning

confidence: 94%

Methane Conversion to Ethylene and Aromatics on PtSn Catalysts

et al. 2017

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Pt and PtSn catalysts supported on SiO2 and H-ZSM-5 were studied for methane conversion under nonoxidative conditions. Addition of Sn to Pt/SiO2 increased the turnover frequency for production of ethylene by a factor of 3, and pretreatment of the catalyst at 1123 K reduced the extent of coke formation. Pt and PtSn catalysts supported on H-ZSM-5 zeolite were prepared to improve the activity and selectivity to non-coke products. Ethylene formation rates were 20 times faster over a PtSn(1:3)/H-ZSM-5 catalyst with SiO2:Al2O3 = 280 in comparison to those over PtSn(3:1)/SiO2. H-ZSM-5-supported catalysts were also active for the formation of aromatics, and the rates of benzene and naphthalene formation were increased by using more acidic H-ZSM-5 supports. These catalysts operate through a bifunctional mechanism, in which ethylene is first produced on highly dispersed PtSn nanoparticles and then is subsequently converted to benzene and naphthalene on Brønsted acid sites within the zeolite support. The most active and stable PtSn catalyst forms carbon products at a rate, 2.5 mmol of C/((mol of Pt) s), which is comparable to that of state-of-the-art Mo/H-ZSM-5 catalysts with same metal loading operated under similar conditions (1.8 mmol of C/((mol of Mo) s)). Scanning transmission electron microscopy measurements suggest the presence of smaller Pt nanoparticles on H-ZSM-5-supported catalysts, in comparison to SiO2-supported catalysts, as a possible source of their high activity. A microkinetic model of methane conversion on Pt and PtSn surfaces, built using results from density functional theory calculations, predicts higher coupling rates on bimetallic and stepped surfaces, supporting the experimental observations that relate the high catalytic activity to small PtSn particles.

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Section: Introductionmentioning

confidence: 94%

Methane Conversion to Ethylene and Aromatics on PtSn Catalysts

et al. 2017

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“…It was suggested that ZSM-5 zeolite was one of the most suitable supports, and molybdenum was the proper metal component . A variety of synthesis techniques and promoters were applied to improve the overall catalytic performance in conventional fixed-bed reactors. − Various catalysts have been developed through modification of the structural feature of the zeolite supports, − adjusting metal species and acidity with the intention of enhancing the catalytic activity, stability, and selectivity to aromatics. − …”

Section: Development Of Catalysts For Mdamentioning

confidence: 99%

“…Moreover, the coke deposit reduced from 30% to 15% at 0.05 wt % of Sn. Furthermore, they synthesized platinum and tin species modified Mo/HZSM-5 zeolite catalysts for MDA . It was concluded that the catalytic performances of catalysts with additional tin led to lower methane conversion but higher aromatic products selectivity.…”

Section: Development Of Catalysts For Mdamentioning

confidence: 99%

Progress in Nonoxidative Dehydroaromatization of Methane in the Last 6 Years

Sun

Ginosar

et al. 2018

Ind. Eng. Chem. Res.

109

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Revolutionary shale gas production has resulted in increasing interest in the use of methane for producing various types of high-value chemicals and among them is aromatics via methane dehydroaromatization (MDA). Progresses achieved in the area of MDA during the last 6 years are significant. However, a review in this area is lacking. This review is designed to fill the gap. The review not only discusses he development of MDA catalysts, including conventional molybdenum (Mo)-based catalyst and non-Mo-based catalysts and novel catalysts. Also, the insights for the associated reaction mechanisms and catalyst regeneration methods and applications of various types of reactors are provided.

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“…Mo/W oxide supported on ZSM-5/MCM-22 is a well-studied bifunctional catalyst for methane dehydroaromatization [2,25]. It has been reported that the metal carbide species produced from Mo/W oxides activate methane by forming CH x species, which is dimerized into C 2 H y species [13,26]. Previously, this group demonstrated high activity and strong aromatic selectivity for methane dehydroaromatization (MDHA) using Mo oxide doped on sulfated zirconia (SZ) solid acid catalysts [15].…”

Section: Introductionmentioning

confidence: 99%