scholarly journals Furfural Hydrogenation on Modified Niobia

2019 ◽  
Vol 9 (11) ◽  
pp. 2287 ◽  
Author(s):  
Andrea Jouve ◽  
Stefano Cattaneo ◽  
Daniel Delgado ◽  
Nicola Scotti ◽  
Claudio Evangelisti ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Lewis Acid ◽  
Furfuryl Alcohol ◽  
Surface Acidity ◽  
High Surface ◽  
Pt Nanoparticles ◽  
Acid Sites ◽  
High Catalytic Activity ◽  
Lewis Acid Sites ◽  
Furfural Hydrogenation

In this study, niobia-based materials have been used as supports for Pt nanoparticles and used in the hydrogenation of furfural. The incorporation of dopants (W6+ and Ti4+) in the Nb2O5 structure induced modifications in the surface acidity of the support; in particular, the addition of W6+ increased the amount of Lewis acid sites, while the addition of Ti4+ decreased the number of Lewis acid sites. As a result, the catalytic activity towards the hydrogenation of furfural was affected; high surface acidity resulted in high catalytic activity. The selectivity of the reaction changed with the support acidity as well, with higher amount of furfuryl alcohol produced decreasing the Lewis acid sites.

Catalytic dehydrofluorination of 1,1,1,2-tetrafluoroethane to synthesize trifluoroethylene over a modified NiO/Al2O3 catalyst

2015 ◽  
Vol 5 (6) ◽  
pp. 3103-3107 ◽  
Author(s):  
Wenzhi Jia ◽  
Min Liu ◽  
Xuewei Lang ◽  
Chao Hu ◽  
Junhui Li ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Linear Relationship ◽  
Lewis Acid ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
Al2o3 Catalyst

The close linear relationship between Lewis acid sites and catalytic activity for the dehydrofluorination of CF3CFH2.

scholarly journals High Surface Area VOx/TiO2/SBA-15 Model Catalysts for Ammonia SCR Prepared by Atomic Layer Deposition

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1386
Author(s):  
Jun Shen ◽  
Christian Hess
Keyword(s):  
Atomic Layer Deposition ◽  
Lewis Acid ◽  
High Surface ◽  
High Surface Area ◽  
Atomic Layer ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
X Ray ◽  
Nox Conversion ◽  
Layer Deposition

The mode of operation of titania-supported vanadia (VOx) catalysts for NOx abatement using ammonia selective catalytic reduction (NH3-SCR) is still vigorously debated. We introduce a new high surface area VOx/TiO2/SBA-15 model catalyst system based on mesoporous silica SBA-15 making use of atomic layer deposition (ALD) for controlled synthesis of titania and vanadia multilayers. The bulk and surface structure is characterized by X-ray diffraction (XRD), UV-vis and Raman spectroscopy, as well as X-ray photoelectron spectroscopy (XPS), revealing the presence of dispersed surface VOx species on amorphous TiO2 domains on SBA-15, forming hybrid Si–O–V and Ti–O–V linkages. Temperature-dependent analysis of the ammonia SCR catalytic activity reveals NOx conversion levels of up to ~60%. In situ and operando diffuse reflection IR Fourier transform (DRIFT) spectroscopy shows N–Hstretching modes, representing adsorbed ammonia and -NH2 and -NH intermediate structures on Bronsted and Lewis acid sites. Partial Lewis acid sites with adjacent redox sites are proposed as the active sites and desorption of product molecules as the rate-determining step at low temperature. The high NOx conversion is attributed to the presence of highly dispersed VOx species and the moderate acidity of VOx supported on TiO2/SBA-15.

Lewis acid sites in MOFs supports promoting the catalytic activity and selectivity for CO esterification to dimethyl carbonate

2020 ◽  
Vol 10 (6) ◽  
pp. 1699-1707 ◽  
Author(s):  
Yu-Ping Xu ◽  
Zhi-Qiao Wang ◽  
Hong-Zi Tan ◽  
Kai-Qiang Jing ◽  
Zhong-Ning Xu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Lewis Acid ◽  
Dimethyl Carbonate ◽  
Metal Organic Frameworks ◽  
Acid Sites ◽  
Lewis Acidity ◽  
Catalyst Supports ◽  
Lewis Acid Sites ◽  
Metal Organic

We studied the effect of Lewis acidity in metal–organic frameworks (MOFs) on their activity as catalyst supports for the esterification of CO to dimethyl carbonate.

Hydrogenation of pentenal over supported Pt nanoparticles: influence of Lewis-acid sites in the conversion pathway

2021 ◽  
Author(s):  
Xuejiao Wei ◽  
Yajuan Zhou ◽  
Xiaonan Sun ◽  
Fuhua Jiang ◽  
Jintao Zhang ◽  
...  
Keyword(s):  
Surface Properties ◽  
Lewis Acid ◽  
High Selectivity ◽  
Pt Nanoparticles ◽  
Acid Sites ◽  
Electron Acceptors ◽  
Acidic Site ◽  
Lewis Acid Sites ◽  
Lewis Acidic Site

The superb TOF and high selectivity of Pt/CeAl are associated with the surface properties (e.g. medium Lewis acidic site). The unsaturated Ce4+/Al3+ cations pairs act as the acid sites and electron acceptors to polarize the CO bonds.

Nanocrystalline Rhenium-doped TiO2: an efficient catalyst in the one-pot conversion of carbohydrates into levulinic acid. The synergistic effect between Brønsted and Lewis acid sites

2021 ◽  
Author(s):  
Sorin Avramescu ◽  
Cristian D. Ene ◽  
Madalina Ciobanu ◽  
Josefine Schnee ◽  
François Devred ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Synergistic Effect ◽  
Lewis Acid ◽  
Levulinic Acid ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
One Pot ◽  
Efficient Catalyst ◽  
The One ◽  
Brønsted And Lewis Acid

Catalytic activity of TiO2, 2%Re-TiO2 and 10%Re-TiO2 in the conversion of carbohydrates into levulinic acid under autoclave conditions was evaluated. These materials were prepared by aerogel method and characterized by...

Efficient conversion of cellulose to 5-hydroxymethylfurfural catalyzed by a cobalt-phosphonate catalyst

2020 ◽  
Vol 4 (11) ◽  
pp. 5795-5801 ◽  
Author(s):  
Xiao Liu ◽  
Xue Min ◽  
Hui Liu ◽  
Yuanqiao Cao ◽  
Yadong Liu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Lewis Acid ◽  
Acid Sites ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Lewis Acid Sites ◽  
Efficient Conversion ◽  
Brönsted Acid

A cobalt-phosphonate network catalyst containing both Brønsted acid and Lewis acid sites is designed and synthesized for the conversion of saccharides to HMF. The catalyst can be recycled four times without the loss of catalytic activity.

scholarly journals A Combined Catalyst of Pt Nanoparticles and TiO 2 with Water‐Tolerant Lewis Acid Sites for One‐Pot Conversion of Glycerol to Lactic Acid

ChemCatChem ◽  
2016 ◽  
Vol 8 (6) ◽  
pp. 1094-1099 ◽  
Author(s):  
Tasuku Komanoya ◽  
Ayaka Suzuki ◽  
Kiyotaka Nakajima ◽  
Masaaki Kitano ◽  
Keigo Kamata ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lewis Acid ◽  
Pt Nanoparticles ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
One Pot
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