scholarly journals Using Transient XAS to Detect Minute Levels of Reversible S-O Exchange at the Active Sites of MoS2-Based Hydrotreating Catalysts: Effect of Metal Loading, Promotion, Temperature, and Oxygenate Reactant

ACS Catalysis ◽  
2021 ◽  
pp. 633-647
Author(s):  
Abhijeet Gaur ◽  
Matthias Stehle ◽  
Marc-André Serrer ◽  
Magnus Zingler Stummann ◽  
Camille La Fontaine ◽  
...  
Keyword(s):  
Active Sites ◽  
Hydrotreating Catalysts ◽  
Metal Loading

Performance of Transition Metal Ions Exchanged Zeolite 13X in Greenhouse Gas Reduction

2007 ◽  
Author(s):  
K. S. Hui ◽  
Christopher Y. H. Chao ◽  
C. W. Kwong ◽  
M. P. Wan
Keyword(s):  
Activation Energy ◽  
Catalytic Activity ◽  
Transition Metal ◽  
Apparent Activation Energy ◽  
Surface Area ◽  
Active Sites ◽  
Methane Combustion ◽  
Bet Surface Area ◽  
Metal Loading ◽  
Zeolite 13X

This study investigated the performance of multi-transition metal (Cu, Cr, Ni and Co) ions exchanged zeolite 13X catalysts on methane emission abatement, especially at methane level of the exhaust from natural gas fueled vehicles. Catalytic activity of methane combustion using multi-ions exchanged catalyst was studied under different parameters: mole % of metal loading, inlet velocity and inlet methane concentration at atmospheric pressure and 500 °C. Performance of the catalysts was investigated and explained in terms of the apparent activation energy, number of active sites and BET surface area of the catalyst. This study showed that the multi-ions exchanged catalyst outperformed the single-ions exchanged and the acidified 13X catalysts. Lengthening the residence time could also lead to higher methane conversion %. Catalytic activity of the catalysts was influenced by the mole % of metal loading which played important roles in affecting the apparent activation energy of methane combustion, active sites and also the BET surface area of the catalyst. Increasing mole % of metal loading in the catalyst decreased the apparent activation energy for methane combustion and also the BET surface area of the catalyst. In view of these, there existed an optimized mole % of metal loading where the highest catalytic activity was observed.

Carbon Dioxide Hydrogenation to Methanol over Cu/ZnO-SBA-15 Catalyst: Effect of Metal Loading

2017 ◽  
Vol 380 ◽  
pp. 151-160 ◽  
Author(s):  
Sara Faiz Hanna Tasfy ◽  
Noor Asmawati Mohd Zabidi ◽  
Maizatul Shima Shaharun ◽  
Duvvria Subbarao ◽  
Ahmed Elbagir
Keyword(s):  
Catalytic Activity ◽  
Carbon Source ◽  
Active Sites ◽  
Low Cost ◽  
Fixed Bed ◽  
Textural Properties ◽  
Catalytic Performance ◽  
Hydrogenation Reaction ◽  
Supported Metal Catalysts ◽  
Metal Loading

Utilization of CO2 as a carbon source to produce valuable chemicals is one of the important ways to reduce the global warming caused by increasing CO2 in the atmosphere. Supported metal catalysts are crucial to produce clean and renewable fuels and chemicals from the stable CO2 molecules. The catalytic conversion of CO2 into methanol is recently under increased scrutiny as an opportunity to be used as a low-cost carbon source. Therefore, a series of the bimetallic Cu/ZnO-based catalyst supported by SBA-15 were synthesized via an impregnation technique with different total metal loading and tested in the catalytic hydrogenation of CO2 to methanol. The morphological and textural properties of the synthesized catalysts were determined by transmission electron microscopy (TEM), temperature programmed desorption, reduction, oxidation and pulse chemisorption (TPDRO), and N2-adsorption. The CO2 hydrogenation reaction was performed in a microactivity fixed-bed system at 250oC, 2.25 MPa, and H2/CO2 ratio of 3. Experimental results showed that the catalytic structure and performance were strongly affected by the loading of the active site. Where, the catalytic activity, the methanol selectivity as well as the space-time yield increased with increasing the metal loading until it reaches the maximum values at a metal loading of 15 wt% while further addition of metal inhibits the catalytic performance. The higher catalytic activity of 14% and methanol selectivity of 92% was obtained over a Cu/ZnO-SBA-15 catalyst with a total bimetallic loading of 15 wt%. The excellent performance of 15 wt% Cu/ZnO-SBA-15 catalyst is attributed to the presence of well dispersed active sites with small particle size, higher Cu surface area, and lower catalytic reducibility.

Structure and Nature of the Active Sites in CoMo Hydrotreating Catalysts Conversion of Thiophene

1998 ◽  
Vol 175 (1) ◽  
pp. 108-116 ◽  
Author(s):  
R.G. Leliveld ◽  
A.J. van Dillen ◽  
J.W. Geus ◽  
D.C. Koningsberger
Keyword(s):  
Active Sites ◽  
Hydrotreating Catalysts

scholarly journals Probing the Active Sites of MoS2 Based Hydrotreating Catalysts Using Modulation Excitation Spectroscopy

ACS Catalysis ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 2568-2579 ◽  
Author(s):  
Abhijeet Gaur ◽  
Trine Marie Hartmann Dabros ◽  
Martin Høj ◽  
Alexey Boubnov ◽  
Tim Prüssmann ◽  
...  
Keyword(s):  
Active Sites ◽  
Hydrotreating Catalysts ◽  
Modulation Excitation Spectroscopy ◽  
Modulation Excitation

scholarly journals Structure and Nature of the Active Sites in CoMo Hydrotreating Catalysts. An EXAFS Study of the Reaction with Selenophene

1997 ◽  
Vol 101 (51) ◽  
pp. 11160-11171 ◽  
Author(s):  
Bob R. G. Leliveld ◽  
Jos A. J. van Dillen ◽  
John W. Geus ◽  
Diek C. Koningsberger ◽  
Mark de Boer
Keyword(s):  
Active Sites ◽  
Hydrotreating Catalysts ◽  
Exafs Study

The effect of sulphidation on the nature of active sites on nickel-molybdenum-alumina hydrorefining catalysts

1983 ◽  
Vol 48 (8) ◽  
pp. 2269-2272 ◽  
Author(s):  
Rafael López
Keyword(s):  
Active Sites ◽  
Strong Influence ◽  
Hydrotreating Catalysts

A strong influence of sulphidation on the hydrogenation and hydrogenolytic activity of Mo-Al2O3 and Ni-Mo-Al2O3 hydrotreating catalysts has been found. Two kinds of active sites are distinguished, the first consisting of surface molybdenum atoms and serving mostly for hydrogenation, the second type formed by interaction of Mo with Ni atoms and being active in sulphided form for direct hydrogenolysis of the C-S bonds.

The influence of metal loading and activation on mesoporous materials supported nickel phosphide hydrotreating catalysts

2009 ◽  
Vol 365 (1) ◽  
pp. 48-54 ◽  
Author(s):  
Tamás I. Korányi ◽  
Alessandro E. Coumans ◽  
Emiel J.M. Hensen ◽  
Ryong Ryoo ◽  
Hei Seung Kim ◽  
...  
Keyword(s):  
Mesoporous Materials ◽  
Nickel Phosphide ◽  
Hydrotreating Catalysts ◽  
Metal Loading

CoMo/Al2O3 hydrotreating catalysts prepared from single Co2Mo10-heteropolyacid at extremely high metal loading

2019 ◽  
Vol 127 ◽  
pp. 51-57 ◽  
Author(s):  
M. Nikulshina ◽  
A. Kokliukhin ◽  
A. Mozhaev ◽  
P. Nikulshin
Keyword(s):  
Hydrotreating Catalysts ◽  
Metal Loading ◽  
High Metal

scholarly journals Nature of active sites in Ni2P hydrotreating catalysts as probed by iron substitution

2015 ◽  
Vol 164 ◽  
pp. 204-216 ◽  
Author(s):  
Haiyan Zhao ◽  
S. Ted Oyama ◽  
Hans-Joachim Freund ◽  
Radosław Włodarczyk ◽  
Marek Sierka
Keyword(s):  
Active Sites ◽  
Hydrotreating Catalysts ◽  
Iron Substitution

What catalysis needs from the electron microscopist

1988 ◽  
Vol 46 ◽  
pp. 694-695
Author(s):  
Alexis T. Bell
Keyword(s):  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Catalyst Deactivation ◽  
Surface Composition ◽  
Internal Surface ◽  
Active Phase ◽  
Atomic Scale ◽  
Metal Catalyst ◽  
Internal Surface Area ◽  
Porous Support

Heterogeneous catalysts, used in industry for the production of fuels and chemicals, are microporous solids characterized by a high internal surface area. The catalyticly active sites may occur at the surface of the bulk solid or of small crystallites deposited on a porous support. An example of the former case would be a zeolite, and of the latter, a supported metal catalyst. Since the activity and selectivity of a catalyst are known to be a function of surface composition and structure, it is highly desirable to characterize catalyst surfaces with atomic scale resolution. Where the active phase is dispersed on a support, it is also important to know the dispersion of the deposited phase, as well as its structural and compositional uniformity, the latter characteristics being particularly important in the case of multicomponent catalysts. Knowledge of the pore size and shape is also important, since these can influence the transport of reactants and products through a catalyst and the dynamics of catalyst deactivation.

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