Direct conversion of methane under nonoxidative conditions

Xu, Yide; Bao, Xinhe; Lin, Liwu

doi:10.1016/s0021-9517(02)00124-0

Cited by 288 publications

(189 citation statements)

References 83 publications

Supporting

Mentioning

184

Contrasting

Unclassified

Order By: Relevance

“…As one of the promising routes for the direct conversion of methane into high value-added chemicals, methane dehydroaromatization (MDA) in the absence of gas-phase oxygen has received considerable attention recently [1][2][3][4][5]. Up to now, the Mo/HZSM-5 catalyst has been proved to be the best one among the tested catalysts; it shows a methane conversion of ca.…”

Section: Introductionmentioning

confidence: 99%

Methane dehydroaromatization over Mo/HZSM-5 catalysts: The reactivity of MoCx species formed from MoOx associated and non-associated with Brönsted acid sites

Shen

Bao

et al. 2005

Applied Catalysis A: General

Self Cite

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Methane dehydroaromatization over Mo/HZSM-5 catalysts: The reactivity of MoCx species formed from MoOx associated and non-associated with Brönsted acid sites

Shen

Bao

et al. 2005

Applied Catalysis A: General

Self Cite

View full text Add to dashboard Cite

“…The MDA reaction is conventionally run at around 700ºC in presence of bifunctional catalysts comprising carbided molybdenum nanoclusters dispersed in acidic shape-selective zeolites such as ZSM-5 and MCM-22 (1). The process suffers from two major hurdles that challenge its further development and industrial implementation: The per-pass conversion to aromatics is limited by thermodynamics, and the catalyst activity rapidly drops with time on stream owing to the accumulation of polyaromatic-type coke on the external zeolite surface that impedes the access to internal active sites (2,3). Attempts to overcome thermodynamic limitations by selective removal of the co-product hydrogen from the MDA reactor using, for instance, Pd-type (4) or ceramic (La 5.5 W 0.6 Mo 0.4 O 11.25-δ ) (5) membranes were not satisfying due to enhanced coke formation that accelerated catalyst decay.…”

mentioning

confidence: 99%

Direct conversion of methane to aromatics in a catalytic co-ionic membrane reactor

Morejudo

Zanón

Escolástico

et al. 2016

Science

355

242

View full text Add to dashboard Cite

Non-oxidative methane dehydroaromatization (MDA:6CH 4 ↔ C 6 H 6 + 9H 2 ) using shapeselective Mo/zeolite catalysts is a technology to exploit stranded natural gas reserves by direct conversion into transportable liquids. The reaction, however, faces two major issues: the onepass conversion/yield is limited by thermodynamics, and the catalyst deactivates fast due to the kinetically-favored formation of coke. Here we show that integration of an electrochemical BaZrO 3 -based membrane exhibiting both proton and oxide ion conductivity into an MDA reactor enables high aromatic yields and outstanding catalyst stability. These effects originate from the simultaneous extraction of hydrogen and distributed injection of oxide ions along the reactor length. Further, we demonstrate that the electrochemical co-ionic membrane reactor enables high carbon efficiencies (up to 80%) significantly improving the techno-economic process viability, and sets the ground for its commercial deployment. One Sentence Summary:The integration of a co-ionic membrane in a MDA reactor remarkably enhances aromatics yield and catalyst lifetime. Main text:

show abstract

“…δ ) 2.2 is typically attributed to Al-OH groups, in which the hydroxyl protons form hydrogen bonds via anchoring to neighboring framework oxygen atoms. 30,32,33 Another hydroxyl group pertaining to the band at around δ ) 1.7 is assigned to Si(OH)(OSi) 3 , i.e., the silanol groups. In consistency with the 29 Si MAS NMR spectra, the band at around δ ) 1.7 was almost undetectable on the post-steam-treated samples.…”

Section: Resultsmentioning

confidence: 99%

“…3,11 Therefore, the dealumination of HZSM-5 or HMCM-22 zeolites, which leads to a decrease in the number of strong Brönsted acid sites, may diminish the driving force for the migration of Mo species into the channels and decrease the amount of Mo species residing in the zeolite channels.…”

Section: Introductionmentioning

confidence: 99%

Post-steam-treatment of Mo/HZSM-5 Catalysts: An Alternative and Effective Approach for Enhancing Their Catalytic Performances of Methane Dehydroaromatization

Wang

Zhuang

et al. 2003

J. Phys. Chem. B

Self Cite

View full text Add to dashboard Cite

Post-steam-treatment is a facile and effective method for improving the catalytic performances of Mo/HZSM-5 catalysts in methane dehydroaromatization under nonoxidative conditions. The treatment can enhance the stability of the catalyst and also give a higher methane conversion and a higher yield of light aromatics, as well as a decrease in the formation rate of carbonaceous deposits. 27 Al, 29 Si, and 1 H multinuclear magic angle spinning nuclear magnetic resonance, X-ray photoelectron spectroscopy, X-ray diffraction, X-ray fluorescence spectroscopy, and thermogravimetric analysis measurements as well as catalytic reaction evaluations were employed to conduct comparative studies on the properties of the catalysts before and after the post-steamtreatment. The results revealed that the number of free Brönsted acid sites per unit cell decreased, while more Mo species migrated into the HZSM-5 channels for the 6Mo/HZSM-5 catalysts after the post-steam-treatment. In addition, the average pore diameter was also larger for the post-steam-treated catalysts, and this was advantageous for mass transport of the reaction products. However, a severe post-steam-treatment, i.e., with longer treating time, of the 6Mo/HZSM-5 catalyst will lead to the formation of the Al 2 (MoO 4 ) 3 phases, which is detrimental to the reaction.

show abstract

Direct conversion of methane under nonoxidative conditions

Cited by 288 publications

References 83 publications

Methane dehydroaromatization over Mo/HZSM-5 catalysts: The reactivity of MoCx species formed from MoOx associated and non-associated with Brönsted acid sites

Methane dehydroaromatization over Mo/HZSM-5 catalysts: The reactivity of MoCx species formed from MoOx associated and non-associated with Brönsted acid sites

Direct conversion of methane to aromatics in a catalytic co-ionic membrane reactor

Post-steam-treatment of Mo/HZSM-5 Catalysts: An Alternative and Effective Approach for Enhancing Their Catalytic Performances of Methane Dehydroaromatization

Contact Info

Product

Resources

About