Brønsted and Lewis Acid Sites in Dealuminated ZSM-12 and β Zeolites Characterized by NH3-STPD, FT-IR, and MAS NMR Spectroscopy

2000 ◽  
Vol 104 (17) ◽  
pp. 4122-4129 ◽  
Author(s):  
Wenmin Zhang ◽  
Panagiotis G. Smirniotis ◽  
M. Gangoda ◽  
Rathindra N. Bose
Keyword(s):  
Nmr Spectroscopy ◽  
Lewis Acid ◽  
Acid Sites ◽  
Mas Nmr ◽  
Lewis Acid Sites ◽  
Ft Ir ◽  
Brønsted And Lewis Acid

On the nature of framework Brønsted and Lewis acid sites in ZSM-5

Zeolites ◽  
1997 ◽  
Vol 19 (4) ◽  
pp. 288-296 ◽  
Author(s):  
G.L. Woolery ◽  
G.H. Kuehl ◽  
H.C. Timken ◽  
A.W. Chester ◽  
J.C. Vartuli
Keyword(s):  
Lewis Acid ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
Brønsted And Lewis Acid

THE USE OF THE COMBINATION OF FTIR, PYRIDINE ADSORPTION, 27Al AND 29Si MAS NMR TO DETERMINE THE BRÖNSTED AND LEWIS ACIDIC SITES

2016 ◽  
Vol 78 (6) ◽  
Author(s):  
Djoko Hartanto ◽  
Lai Sin Yuan ◽  
Sestriana Mutia Sari ◽  
Djarot Sugiarso ◽  
Irmina Kris Murwarni ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Aluminum Atom ◽  
Xrd Analysis ◽  
Acid Sites ◽  
Mas Nmr ◽  
Molar Ratio ◽  
Pyridine Adsorption ◽  
Lewis Acid Sites ◽  
27Al Mas Nmr ◽  
Pre Treatment

Lewis and Brönsted acidity were studied on ZSM-5 with combination of pyridine adsorption and FTIR vibration, ZSM-5 synthesized using kaolin Bangka Indonesia with an increase in the molar ratio of Si/Al 30-60 without pre-treatment and without organic templates and with seeds silicalite. Interestingly, the intensity of the infrared showed an increase of band vibration pyridine as absorbed Brönsted and Lewis acid sites in a molar ratio increase of Si/Al in ZSM-5, indicating an increase in the number of silanol (Brönsted acid) and deformed silica (Lewis acid) because the amount of Aluminum in ZSM-5 decrease with increase Si/Al but amount acidity increase. 29Si and 27Al MAS NMR analysis was supported by the results of infrared to indicate that all of the aluminum atom is coordinated with their neighbors are the same in ordering the ZSM-5 framework and 27Al MAS NMR showed a sharp peak of all the variations of Si/Al except the Si/Al 30 shows a low peak area. XRD analysis supported that the ZSM-5 structure formed is pure and crystal and a decrease in crystallinity proven for more than Si/Al 50, that defects silica occurs in ZSM-5, this corresponds to the growing number of Lewis acid sites caused by defects silica described the infrared results.

scholarly journals The Keggin Structure: An Important Factor in Governing NH3–SCR Activity Over the V2O5–MoO3/TiO2 Catalyst

2018 ◽  
Vol 148 (4) ◽  
pp. 1228-1235 ◽  
Author(s):  
Rui Wu ◽  
Ningqiang Zhang ◽  
Xiaojun Liu ◽  
Lingcong Li ◽  
Liyun Song ◽  
...  
Keyword(s):  
Low Temperature ◽  
Catalytic Reduction ◽  
Physicochemical Characteristics ◽  
Acid Sites ◽  
Keggin Structure ◽  
Lewis Acid Sites ◽  
Nh3 Scr ◽  
Strong Acidity ◽  
Ft Ir ◽  
Brønsted And Lewis Acid

Abstract Heteropolyacids and their salts have been effectively used in selective catalytic reduction because of the Keggin structure and extraordinarily strong acidity. Catalysts with and without the Keggin structure were synthesized to further investigate the effects of heteropolyoxometallate on low temperature NH3–SCR. XRD, BET, Raman, H2–TPR, NH3–TPD, FT-IR, and SO2–TPD techniques were used to characterize the physicochemical characteristics of the catalysts. Results indicate that catalysts with the Keggin structure had more surface Brönsted and Lewis acid sites, and these catalysts had significantly improved performances in the SCR reaction and in SO2 poisoning resistance. Graphical Abstract

Enhancing Brønsted and Lewis Acid Sites of the Utilized Spent RFCC Catalyst Waste for the Continuous Cracking Process of Palm Oil to Biofuels

2020 ◽  
Vol 59 (20) ◽  
pp. 9459-9468 ◽  
Author(s):  
I. Istadi ◽  
Teguh Riyanto ◽  
Luqman Buchori ◽  
Didi Dwi Anggoro ◽  
G. Gilbert ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Palm Oil ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
Cracking Process ◽  
Brønsted And Lewis Acid

High activity of aluminated bifunctional mesoporous silica nanoparticles for cumene hydrocracking and measurement of molar absorption coefficient

2015 ◽  
Vol 39 (10) ◽  
pp. 8006-8016 ◽  
Author(s):  
Mohammad Reza Sazegar ◽  
Sugeng Triwahyono ◽  
Aishah Abdul Jalil ◽  
Rino R. Mukti ◽  
Seyed Mohammad Seyed Mohaghegh ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Absorption Coefficient ◽  
Silica Nanoparticles ◽  
High Activity ◽  
Lewis Acid ◽  
Mesoporous Silica Nanoparticles ◽  
Acid Sites ◽  
Molar Absorption Coefficient ◽  
Lewis Acid Sites ◽  
Brønsted And Lewis Acid

Pt/HAlMSN synthesized with Si/Al ratios = 7–50 showed high activity in cumene hydrocracking due to the Brønsted and Lewis acid sites.

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