In situ diffuse reflectance FTIR study of the selective catalytic reduction of NO by NH[sub 3] over vanadia-titania aerogels

Journal Article · Sun May 01 00:00:00 EDT 1994 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1994.1109· OSTI ID:7036699

Schneider, H; Tschudin, S; Schneider, M; Baiker, A ^[1]; Wokaun, A ^[2]

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1. Swiss Federal Institute of Technology, Zuerich (Switzerland)
2. Univ. of Bayreuth (Germany)

Selective catalytic reduction of NO by NH[sub 3] (SCR) on high surface area (BET > 180 m[sup 2] g[sup [minus]1]) vanadia-titania aerogels with 5, 10, and 20 wt% of vanadia, has been investigated by diffuse reflectance FTIR spectroscopy coupled with mass spectrometry under reaction conditions and by temperature-programmed desorption of preadsorbed NH[sub 3] and NO. The SCR activity of these catalysts increases with the vanadia loading. This behaviour is reflected by the temperatures necessary to reach 50% NO conversion under standard conditions, which decreased in the sequence 5% V[sub 2]O[sub 5], 545 K; 10% V[sub 2]O[sub 5], 470 K; 20% V[sub 2]O[sub 5], 440 K. A similarly prepared high surface area (182 m[sup 2] g[sup [minus]1]) titania aerogel does not exhibit significant NO conversion in this temperature range. On pure titania aerogel, mainly Lewis-bound ammonia is observed subsequent to NH[sub 3] adsorption at ambient temperature. In contrast, it is shown that Bronsted-bound ammonia, characterized by bands at 1660 and 1414 cm[sup [minus]1], is involved in the SCR reaction. The SCR activities correlate with the fraction of Bronsted-bound ammonia which significantly increases with the vanadia loading of the aerogel samples. 29 refs., 10 figs.

• OSTI ID: 7036699
• Journal Information: Journal of Catalysis; (United States), Vol. 147:1; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
NITRIC OXIDE
SELECTIVE CATALYTIC REDUCTION
TITANIUM OXIDES
CATALYTIC EFFECTS
VANADIUM OXIDES
ABSORPTION SPECTROSCOPY
HETEROGENEOUS CATALYSIS
MASS SPECTROSCOPY
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0400-1000 K
CATALYSIS
CHALCOGENIDES
CHEMICAL REACTIONS
DENITRIFICATION
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
REDUCTION
SPECTROSCOPY
TEMPERATURE RANGE
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
VANADIUM COMPOUNDS
400201* - Chemical & Physicochemical Properties