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

Shen, Jun ; Hess, Christian (2021):
High Surface Area VOₓ/TiO₂/SBA-15 Model Catalysts for Ammonia SCR Prepared by Atomic Layer Deposition. (Publisher's Version)
In: Catalysts, 10 (12), MDPI, e-ISSN 2073-4344,
DOI: 10.26083/tuprints-00019276,
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Item Type: Article
Origin: Secondary publication via sponsored Golden Open Access
Status: Publisher's Version
Title: High Surface Area VOₓ/TiO₂/SBA-15 Model Catalysts for Ammonia SCR Prepared by Atomic Layer Deposition
Language: English
Abstract:

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.

Journal or Publication Title: Catalysts
Journal volume: 10
Number: 12
Publisher: MDPI
Collation: 25 Seiten
Classification DDC: 500 Naturwissenschaften und Mathematik > 540 Chemie
Divisions: 07 Department of Chemistry > Fachgebiet Anorganische Chemie
07 Department of Chemistry > Physical Chemistry
Date Deposited: 09 Aug 2021 08:06
Last Modified: 09 Aug 2021 08:06
DOI: 10.26083/tuprints-00019276
Corresponding Links:
URN: urn:nbn:de:tuda-tuprints-192766
URI: https://tuprints.ulb.tu-darmstadt.de/id/eprint/19276
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