Probing the Metal-Support Interaction in Carbon-Supported Catalysts by using Electron Microscopy

ChemCatChem ◽  
2015 ◽  
Vol 7 (22) ◽  
pp. 3639-3645 ◽  
Author(s):  
Bingsen Zhang ◽  
Dang Sheng Su
Keyword(s):  
Electron Microscopy ◽  
Supported Catalysts ◽  
Support Interaction ◽  
Metal Support Interaction ◽  
Metal Support

Co-processing of hydrodeoxygenation and hydrodesulfurization of phenol and dibenzothiophene with NiMo/Al2O3–ZrO2 and NiMo/TiO2–ZrO2 catalysts

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jesús Andrés Tavizón Pozos ◽  
Gerardo Chávez Esquivel ◽  
Ignacio Cervantes Arista ◽  
José Antonio de los Reyes Heredia ◽  
Víctor Alejandro Suárez Toriello
Keyword(s):  
Active Sites ◽  
Reaction Rate ◽  
Supported Catalysts ◽  
Initial Reaction Rate ◽  
Initial Reaction ◽  
Competition Effect ◽  
Support Interaction ◽  
Highly Active ◽  
Metal Support Interaction ◽  
Metal Support

Abstract The influence of Al2O3–ZrO2 and TiO2–ZrO2 supports on NiMo-supported catalysts at a different sulfur concentration in a model hydrodeoxygenation (HDO)-hydrodesulfurization (HDS) co-processing reaction has been studied in this work. A competition effect between phenol and dibenzothiophene (DBT) for active sites was evidenced. The competence for the active sites between phenol and DBT was measured by comparison of the initial reaction rate and selectivity at two sulfur concentrations (200 and 500 ppm S). NiMo/TiO2–ZrO2 was almost four-fold more active in phenol HDO co-processed with DBT than NiMo/Al2O3–ZrO2 catalyst. Consequently, more labile active sites are present on NiMo/TiO2–ZrO2 than in NiMo/Al2O3–ZrO2 confirmed by the decrease in co-processing competition for the active sites between phenol and DBT. DBT molecules react at hydrogenolysis sites (edge and rim) preferentially so that phenol reacts at hydrogenation sites (edge and edge). However, the hydrogenated capacity would be lost when the sulfur content was increased. In general, both catalysts showed similar functionalities but different degrees of competition according to the highly active NiMoS phase availability. TiO2–ZrO2 as the support provided weaker metal-support interaction than Al2O3–ZrO2, generating a larger fraction of easily reducible octahedrally coordinated Mo- and Ni-oxide species, causing that NiMo/TiO2–ZrO2 generated precursors of MoS2 crystallites with a longer length and stacking but with a higher degree of Ni-promotion than NiMo/Al2O3–ZrO2 catalyst.

scholarly journals Synthesis of multi-walled carbon nanotubes with controlled inner and outer diameters by ethylene decomposition over Ni/MgO and Co/MgO catalysts

2018 ◽  
Vol 36 (4) ◽  
pp. 739-747 ◽  
Author(s):  
N.V. Lemesh ◽  
P.E. Strizhak
Keyword(s):  
Carbon Nanotubes ◽  
Growth Mechanism ◽  
Supported Catalysts ◽  
Support Interaction ◽  
Ethylene Decomposition ◽  
Metal Support Interaction ◽  
Metal Support ◽  
Multi Walled Carbon Nanotubes ◽  
Co Nanoparticles ◽  
Walled Carbon Nanotubes

AbstractIn this work, multi-walled carbon nanotubes (MWCNTs) with significantly different mean diameters were produced by catalytic CVD over Ni and Co-based supported catalysts. Our results indicate that Ni nanoparticles in the Ni/MgO catalyst are responsible for controlling the inner diameters of the carbon nanotubes. Contrary, Co nanoparticles in the Co/MgO catalyst control the outer diameters of MWCNTs. The “base-growth” mechanism and smaller diameters of the MWCNTs grown on the Ni/MgO catalyst are associated with a strong metal-support interaction (SMSI) resulting from NixMg1−xO mixed oxide formation. The concept of the weak metal-support interaction (WMSI) between Co nanoparticles and MgO for the Co/MgO catalyst confirms the “tip-growth” mechanism of the MWCNTs.

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