Investigating the Influence of Mesoporosity in Zeolite Beta on Its Catalytic Performance for the Conversion of Methanol to Hydrocarbons

Liu, Zhaohui; Dong, Xinglong; Zhu, Yihan; Emwas, Abdul‐Hamid; Zhang, Daliang; Tian, Qiwei; Han, Yu

doi:10.1021/acscatal.5b01350

Cited by 91 publications

(66 citation statements)

References 59 publications

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“…Analysis by energy dispersive X-ray (EDX) mapping allows ac lear assessment of the distribution of zirconium and titanium. [33] As shown in the images in Figure 2d-g, zirconium shows ad istribution similart ot itanium, and the same phenomenon was observed in other randomly Figure S3). Particularly,e ven in the high-resolutione lementalm aps (region II in Figure S3), the distribution of zirconium is still consistent with that of titanium, indicating the uniform distribution of zirconium species on TiO 2 .I nt he elemental maps obtained from electron microscopy,t he sulfur elementi se asily to be observed, confirmingt he successful sulfation of the Zr-TiO 2 surface (Supporting Information, Figures S4 and S5).…”

supporting

confidence: 77%

“…For this sample, it is difficult to distinguish ZrO 2 from TiO 2 in the STEM images, which might be due to the strong dispersion of ZrO 2 species on TiO 2 anatase crystals. Analysis by energy dispersive X‐ray (EDX) mapping allows a clear assessment of the distribution of zirconium and titanium . As shown in the images in Figure d–g, zirconium shows a distribution similar to titanium, and the same phenomenon was observed in other randomly selected regions (Supporting Information, Figure S3).…”

Section: Figurementioning

confidence: 75%

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Rational Design of Zirconium‐doped Titania Photocatalysts with Synergistic Brønsted Acidity and Photoactivity

Wang

Zhang

et al. 2016

ChemSusChem

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The preparation of photocatalysts with high activities under visible-light illumination is challenging. We report the rational design and construction of a zirconium-doped anatase catalyst (S-Zr-TiO ) with Brønsted acidity and photoactivity as an efficient catalyst for the degradation of phenol under visible light. Electron microscopy images demonstrate that the zirconium sites are uniformly distributed on the sub-10 nm anatase crystals. UV-visible spectrometry indicates that the S-Zr-TiO is a visible-light-responsive catalyst with narrower band gap than conventional anatase. Pyridine-adsorption infrared and acetone-adsorption C NMR spectra confirm the presence of Brønsted acidic sites on the S-Zr-TiO sample. Interestingly, the S-Zr-TiO catalyst exhibits high catalytic activity in the degradation of phenol under visible-light illumination, owing to a synergistic effect of the Brønsted acidity and photoactivity. Importantly, the S-Zr-TiO shows good recyclability.

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supporting

confidence: 77%

Section: Figurementioning

confidence: 75%

Rational Design of Zirconium‐doped Titania Photocatalysts with Synergistic Brønsted Acidity and Photoactivity

Wang

Zhang

et al. 2016

ChemSusChem

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“…Large‐pore 12‐MR molecular sieves are generally employed for mechanism elucidation, and Beta zeolite with low Si/Al ratio is the favorite model material . Due to the lack of space limitation and high acid concentration, the aromatics cycle prevails in the reaction, yielding C 4 + aliphatics and aromatics as the main products . Recently, high‐silica Beta zeolites (Si/Al > 100) with low acid density were employed in MTO reaction and yielded a surprising propylene selectivity (up to 58% at 550 °C) together with a high propylene/ethylene ratio (>10) and long lifetime .…”

Section: Fundamental Understanding On the Zeolite‐catalyzed Mto Reactionmentioning

confidence: 99%

Recent Progress in Methanol‐to‐Olefins (MTO) Catalysts

et al. 2019

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Among the 8-MR molecular sieves, silicoaluminophosphate SAPO-34 with 3D channels and moderate acid strength represents the most interesting one, the light olefins selectivity of which could reach up to 90% or even higher. [7] The excellent MTO performance of SAPO-34 was first reported by Dalian Institute of Chemical Physics (DICP) in 1990. [8] The researchers also demonstrated the good regeneration stability and high-temperature steam stability of Inspired by these pioneering discoveries, extensive research efforts have been devoted to SAPO-34 focusing on the elucidation of its crystallization mechanism, synthesis optimization, and the relevant catalytic studies, which greatly promote the technological development of the MTO process. Although SAPO-34 exhibits high catalytic activity and high selectivity toward light olefins, it suffers a rapid deactivation due to the coke deposition. Moreover, the MTO reaction on SAPO-34 catalyst is highly exothermal. These features determine that the industrial MTO process based on SAPO-34 catalyst has to adopt fluidized bed reactor, which allows efficient heat transfer and enables the continuous regeneration of the catalyst. In 2010, the world's first commercial MTO unit was successfully commissioned in Baotou, China by DICP (named DMTO technology). [5,10] The production capacity of ethylene and propylene is 0.6 Mt a −1 . To supply commercial catalysts for the DMTO unit, a 2000 t a −1 catalyst manufacturing plant was started up in Dalian in 2008. Afterward, DICP developed the DMTO-II technology, in which the byproducts of C 4 + are separated and introduced into a fluidized-bed cracking reactor to improve the yields of ethylene and propylene. Both the cracking unit and the MTO unit share one regenerator and use the same catalyst. By the end of 2018, thirteen DMTO units have been put into operation with a total production capacity of 7.16 Mt a −1 . Moreover, DICP launched the new generation of DMTO catalyst and completed the pilot test of the DMTO-III technology in 2018, both of which aim to further improve the olefins yield of DMTO units. The catalyst and technology development of the DMTO process are summarized in Figure 1.Based on SAPO-34 catalyst, UOP and Norsk Hydro also developed an MTO process with a low-pressure fast fluidizedbed reactor. [11] In 2013, a commercialized MTO plant (0.3 Mt a −1 olefins) was commissioned in Nanjing, China, which combines the UOP/Hydro MTO process and the total/UOP olefin cracking process to enhance the yield of ethylene and propylene. In addition, Shanghai Research Institute of Petrochemical Technology Methanol conversion to olefins, as an important reaction in C1 chemistry, provides an alternative platform for producing basic chemicals from nonpetroleum resources such as natural gas and coal. Methanol-to-olefin (MTO) catalysis is one of the critical constraints for the process development, determining the reactor design, and the profitability of the process. After the construction and commissioning of the world's first MTO plant by Dalian I...

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“…Ethylene selectivity wasu sed as an indicator for the degree of the propagation through polymethylated benzenes, [51] whereas the C 4 + selectivity was used for assessing the importance of propagationt hrough the olefins-based cycle. [51] We will discuss the activity resultsb yc omparing bulk and sheet-like zeolites. It is seen that [Al]MFI-sheet zeolite remains active much longert han its bulk counterpart at weighth ourly space velocity( WHSV) values of 2h À1 and 6h À1 .T his result is in line with earlier studies, demonstrating the superior performance of the nanostructured zeolite.…”

Section: Catalytic Activity Measurementsmentioning

confidence: 99%

On the Role of Acidity in Bulk and Nanosheet [T]MFI (T=Al³⁺_, Ga³⁺, Fe³⁺, B³⁺) Zeolites in the Methanol‐to‐Hydrocarbons Reaction

et al. 2017

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The influence of framework substituents (Al3+, Ga3+, Fe3+ and B3+) and morphology (bulk vs. nanometer‐sized sheets) of MFI zeolites on the acidity and catalytic performance in the methanol‐to‐hydrocarbons (MTH) reaction was investigated. The Brønsted acid density and strength decreased in the order Al(OH)Si>Ga(OH)Si>Fe(OH)Si≫B(OH)Si. Pyridine 15N NMR spectra confirmed the differences in the Brønsted and Lewis acid strengths but also provided evidence for site heterogeneity in the Brønsted acid sites. Owing to the lower efficiency with which tervalent ions can be inserted into the zeolite framework, sheet‐like zeolites exhibited lower acidity than bulk zeolites. The sheet‐like Al‐containing MFI zeolite exhibited the greatest longevity as a MTH catalyst, outperforming its bulk [Al]MFI counterpart. Although the lower acidity of bulk [Ga]MFI led to a better catalytic performance than bulk [Al]MFI, the sheet‐like [Ga]MFI sample was found to be nearly inactive owing to lower and heterogeneous Brønsted acidity. All Fe‐ and B‐substituted zeolite samples displayed very low catalytic performance owing to their weak acidity. Based on the product distribution, the MTH reaction was found to be dominated by the olefins‐based catalytic cycle. The small contribution of the aromatics‐based catalytic cycle was larger for bulk zeolite than for sheet‐like zeolite, indicating that shorter residence time of aromatics can explain the lower tendency toward coking and enhanced catalyst longevity.

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Investigating the Influence of Mesoporosity in Zeolite Beta on Its Catalytic Performance for the Conversion of Methanol to Hydrocarbons

Cited by 91 publications

References 59 publications

Rational Design of Zirconium‐doped Titania Photocatalysts with Synergistic Brønsted Acidity and Photoactivity

Rational Design of Zirconium‐doped Titania Photocatalysts with Synergistic Brønsted Acidity and Photoactivity

Recent Progress in Methanol‐to‐Olefins (MTO) Catalysts

On the Role of Acidity in Bulk and Nanosheet [T]MFI (T=Al³⁺_, Ga³⁺, Fe³⁺, B³⁺) Zeolites in the Methanol‐to‐Hydrocarbons Reaction

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Investigating the Influence of Mesoporosity in Zeolite Beta on Its Catalytic Performance for the Conversion of Methanol to Hydrocarbons

Cited by 91 publications

References 59 publications

Rational Design of Zirconium‐doped Titania Photocatalysts with Synergistic Brønsted Acidity and Photoactivity

Rational Design of Zirconium‐doped Titania Photocatalysts with Synergistic Brønsted Acidity and Photoactivity

Recent Progress in Methanol‐to‐Olefins (MTO) Catalysts

On the Role of Acidity in Bulk and Nanosheet [T]MFI (T=Al3+, Ga3+, Fe3+, B3+) Zeolites in the Methanol‐to‐Hydrocarbons Reaction

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On the Role of Acidity in Bulk and Nanosheet [T]MFI (T=Al³⁺_, Ga³⁺, Fe³⁺, B³⁺) Zeolites in the Methanol‐to‐Hydrocarbons Reaction