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Influence of W loading on the environment of Si in WO3/ZrO2–SiO2 catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
42146 45912 2010 5 PDF Available
Title
Influence of W loading on the environment of Si in WO3/ZrO2–SiO2 catalysts
Abstract

Tungstated zirconias consist typically of WOx species deposited on zirconia support. Additives like Si can be added to stabilize the catalyst surface area. The aim of this work is to identify the location of the Si (surface or bulk) as a function of W addition. Zirconia doped with 1.2 wt% Si remained purely tetragonal and exhibited a high specific surface area (150 m2/g) following calcination at 1023 K. Infrared quantification of the silanol band at 3745 cm−1 indicated that Si is essentially present at the surface. The 29Si NMR chemical shift of the zirconia is characteristic of isolated silicium. This result is corroborated with infrared by the absence of the structural band ascribed to Si–O–Si vibrations. NMR and infrared results indicated that W addition brings about a progressive evolution of the Si environment towards that of silica-like species. These results can be tentatively explained by a ligand enhanced dissolution of the support on W deposition. Si leached from the surface will then aggregate, forming small SiO2-like domains on the zirconia.

Graphical abstractThe location of Si species (surface or bulk) added to stabilize the surface area of tungstated zirconia and their degree of aggregation, were studied as a function of W addition. NMR and infrared results indicated that W addition brings about a progressive evolution of the Si environment towards that of silica-like species.Figure optionsDownload full-size imageDownload high-quality image (68 K)Download as PowerPoint slide

Keywords
Zirconia; 29Si NMR-MAS; Infrared; CO adsorption
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Influence of W loading on the environment of Si in WO3/ZrO2–SiO2 catalysts
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 374, Issues 1–2, 1 February 2010, Pages 137–141
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us