Effects of single and double active sites of Cu oxide clusters over MFI zeolite for direct conversion of methane to methanol: DFT calculations

Physical Chemistry Chemical Physics ◽

10.1039/d0cp05435f ◽

2021 ◽

Author(s):

Watinee Nunthakitgoson ◽

Anawat Thivasasith ◽

Thana Maihom ◽

Chularat Wattanakit

Keyword(s):

Dft Calculations ◽

Active Sites ◽

Direct Conversion ◽

Mfi Zeolite ◽

Zeolite Framework ◽

Conversion Of Methane

In this context, we investigate the effect of the single and double active sites of Cu oxide clusters over the MFI zeolite framework for direct conversion of methane to methanol....

Download Full-text

Active sites and mechanism of the direct conversion of methane and carbon dioxide to acetic acid over the zinc-modified H-ZSM-5 zeolite

Catalysis Science & Technology ◽

10.1039/c9cy01749f ◽

2019 ◽

Vol 9 (22) ◽

pp. 6297-6307 ◽

Cited By ~ 1

Author(s):

Peng Zhang ◽

Xuejing Yang ◽

Xiuli Hou ◽

Jianli Mi ◽

Zhizhong Yuan ◽

...

Keyword(s):

Carbon Dioxide ◽

Acetic Acid ◽

Catalytic Activity ◽

Active Sites ◽

Direct Conversion ◽

Conversion Of Methane ◽

Zeolite P

The catalytic activity of the conversion of CH4 and CO2 on zinc modified H-ZSM-5 is strongly dependent on the structure of the active sites.

Download Full-text

Active sites and mechanisms in the direct conversion of methane to methanol using Cu in zeolitic hosts: a critical examination

Chemical Society Reviews ◽

10.1039/c7cs00709d ◽

2020 ◽

Vol 49 (5) ◽

pp. 1449-1486 ◽

Cited By ~ 13

Author(s):

Mark A. Newton ◽

Amy J. Knorpp ◽

Vitaly L. Sushkevich ◽

Dennis Palagin ◽

Jeroen A. van Bokhoven

Keyword(s):

Critical Review ◽

Active Sites ◽

Direct Conversion ◽

Critical Examination ◽

Selective Conversion ◽

Current State ◽

Conversion Of Methane

In this critical review we examine the current state of our knowledge in respect of the nature of the active sites in copper containing zeolites for the selective conversion of methane to methanol.

Download Full-text

Direct conversion of methane to methanol with zeolites: towards understanding the role of extra-framework d-block metal and zeolite framework type

Dalton Transactions ◽

10.1039/c9dt00922a ◽

2019 ◽

Vol 48 (28) ◽

pp. 10364-10384 ◽

Cited By ~ 9

Author(s):

Samuel Raynes ◽

Meera A. Shah ◽

Russell A. Taylor

Keyword(s):

Methanol Conversion ◽

Direct Conversion ◽

Zeolite Framework ◽

Conversion Of Methane ◽

Cu And Zn

This Perspective article highlights the latest advances in the field of direct methane to methanol conversion by zeolites containing first row, extra-framework d-block metals (Mn, Fe, Co, Ni, Cu and Zn).

Download Full-text

Comparing the Nature of Active Sites in Cu-loaded SAPO-34 and SSZ-13 for the Direct Conversion of Methane to Methanol

Catalysts ◽

10.3390/catal10020191 ◽

2020 ◽

Vol 10 (2) ◽

pp. 191 ◽

Cited By ~ 1

Author(s):

Karoline Kvande ◽

Dimitrios K. Pappas ◽

Michael Dyballa ◽

Carlo Buono ◽

Matteo Signorile ◽

...

Keyword(s):

Active Sites ◽

Co Adsorption ◽

Direct Conversion ◽

Active Species ◽

Ch4 Oxidation ◽

Structure Activity ◽

Conversion Of Methane ◽

Higher Temperature ◽

X Ray Absorption ◽

Better Than

On our route towards a more sustainable future, the use of stranded and underutilized natural gas to produce chemicals would be a great aid in mitigating climate change, due to the reduced CO2 emissions in comparison to using petroleum. In this study, we investigate the performance of Cu-exchanged SSZ-13 and SAPO-34 microporous materials in the stepwise, direct conversion of methane to methanol. With the use of X-ray absorption spectroscopy, infrared (in combination with CO adsorption) and Raman spectroscopy, we compared the structure–activity relationships for the two materials. We found that SSZ-13 performed significantly better than SAPO-34 at the standard conditions. From CH4-TPR, it is evident that SAPO-34 requires a higher temperature for CH4 oxidation, and by changing the CH4 loading temperature from 200 to 300 °C, the yield (μmol/g) of SAPO-34 was increased tenfold. As observed from spectroscopy, both three- and four-fold coordinated Cu-species were formed after O2-activation; among them, the active species for methane activation. The Cu speciation in SAPO-34 is distinct from that in SSZ-13. These deviations can be attributed to several factors, including the different framework polarities, and the amount and distribution of ion exchange sites.

Download Full-text

Copper-Modified Zeolites and Silica for Conversion of Methane to Methanol

Catalysts ◽

10.3390/catal8110545 ◽

2018 ◽

Vol 8 (11) ◽

pp. 545 ◽

Cited By ~ 14

Author(s):

Xueting Wang ◽

Natalia Martin ◽

Johan Nilsson ◽

Stefan Carlson ◽

Johan Gustafson ◽

...

Keyword(s):

Active Sites ◽

Copper Ions ◽

Ambient Pressure ◽

Direct Conversion ◽

Minor Amount ◽

Powder Materials ◽

Methanol Production ◽

Conversion Of Methane ◽

First Time

Powder materials containing copper ions supported on ZSM-5 (Cu-Zeolite Socony Mobil-5) and SSZ-13 (Cu-Standard Oil synthesised zeolite-13), and predominantly CuO nanoparticles on amorphous SiO 2 were synthesised, characterised, wash-coated onto ceramic monoliths and, for the first time, compared as catalysts for direct conversion of methane to methanol (DCMM) at ambient pressure (1 atm) using O 2 , N 2 O and NO as oxidants. Methanol production was monitored and quantified using Fourier transform infrared spectroscopy. Methanol is formed over all monolith samples, though the formation is considerably higher for the copper-exchanged zeolites. Hence, copper ions are the main active sites for DCMM. The minor amount of methanol produced over the Cu/SiO 2 sample, however, suggests that zeolites are not the sole substrate that can host those active copper sites but also silica. Further, we present the first ambient pressure in situ infrared spectroscopic measurements revealing the formation and consumption of surface methoxy species, which are considered to be key intermediates in the DCMM reaction.

Download Full-text

Ultrasound-Assisted Preparation of Mo/ZSM-5 Zeolite Catalyst for Non-Oxidative Methane Dehydroaromatization

Catalysts ◽

10.3390/catal11030313 ◽

2021 ◽

Vol 11 (3) ◽

pp. 313

Author(s):

Heidy Ramirez-Mendoza ◽

Mafalda Valdez Lancinha Pereira ◽

Tom Van Gerven ◽

Cécile Lutz ◽

Ignacio Julian

Keyword(s):

Catalytic Activity ◽

Ion Exchange ◽

Active Sites ◽

Chemical Properties ◽

Successful Implementation ◽

Metal Dispersion ◽

Zeolite Framework ◽

Dispersed Catalysts ◽

Methane Dehydroaromatization ◽

Ultrasound Assisted

The activity and selectivity of Mo/ZSM-5, benchmarking catalyst for the non-oxidative dehydroaromatization of methane, strongly depend on the cluster size, spatial distribution, and chemical environment of the Mo-based active sites. This study discloses the use of an ultrasound-assisted ion-exchange (US-IE) technique as an alternative Mo/ZSM-5 synthesis procedure in order to promote metal dispersion along the zeolite framework. For this purpose, a plate transducer (91.8 kHz) is employed to transmit the ultrasonic irradiation (US) into the ion-exchange reactor. The physico-chemical properties and catalytic activity of samples prepared under the said irradiation procedure and traditional impregnation (IWI) method are critically evaluated. Characterization results suggest that US neither affects the crystalline structure nor the particle size of the parent zeolite. However, US-IE promotes molybdenum species dispersion, avoids clustering at the external fresh zeolite surface and enhances molybdate species anchoring to the zeolite framework with respect to IWI. Despite the improved metal dispersion, the catalytic activity between catalysts synthesized by US-IE and IWI is comparable. This suggests that the sole initial dispersion enhancement does not suffice to boost the catalyst productivity and further actions such ZSM-5 support and catalyst pre-conditioning are required. Nevertheless, the successful implementation of US-IE and the resulting metal dispersion enhancement pave the way toward the application of this technique to the synthesis of other dispersed catalysts and materials of interest.

Download Full-text