Vanadia-Titania aerogels
- Swiss Federal Institute of Technology, Zuerich (Switzerland)
- Univ. of Bayreuth (Germany)
Niobia-doped vanadia-titania aerogels with 20 wt% nominal {open_quotes}V{sub 2}O{sub 5}{close_quotes} and 2-6 wt% nominal {open_quotes}Nb{sub 2}O{sub 5}{close_quotes} have been prepared by a two-stage sol-gel process with subsequent supercritical drying. A titania gel was synthesized by the addition of an acidic hydrolysant to tetrabutoxytitanium(IV) in methanol. The methanoloic, premixed solution of niobium(V) pentaethoxide and vanadium(V) oxide tri-n-propoxide was added after redispersing the titania gel. The influence of niobia loading on the morphological and chemical properties of the aerogels was studied. Similarly a ternary xerogel (20 wt% V{sub 2}O{sub 5}, 6 wt% Nb{sub 2}O{sub 5}) was prepared for comparison with the corresponding aerogel. The aero(xero-)gels were characterized by means of N{sub 2} physisorption, X-ray diffraction, thermal analysis coupled with mass spectrometry, scanning electron microscopy, and vibrational spectroscopy. The catalytic properties of the aero(xero-)gels were tested with the selective catalytic reduction of NO by NH{sub 3}. The variation of the niobia loading from 2 to 6 wt% Nb{sub 2}O{sub 5} did not affect the activity. An increase of the calcination temperature from 573 to 723 K led to a significant activity rise of the aerogel catalysts. The xerogel calcined at 673 K exhibited the highest activity among all catalysts tested. 60 refs., 15 figs., 3 tabs.
- OSTI ID:
- 47974
- Journal Information:
- Journal of Catalysis, Vol. 150, Issue 2; Other Information: PBD: Dec 1994
- Country of Publication:
- United States
- Language:
- English
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