Bibliographic Citation
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DOI | http://dx.doi.org/10.1006/jcat.1996.0364 |
Title | Iron oxide and chromia supported on titania-pillared clay for selective catalytic reduction of nitric oxide with ammonia |
Creator/Author | Cheng, L.S. ; Yang, R.T. [State Univ. of New York, Buffalo, NY (United States)] ; Ning Chen [Univ. of Michigan, Ann Arbor, MI (United States)] |
Publication Date | 1996 Nov 01 |
OSTI Identifier | OSTI ID: 486377 |
DOE Contract Number | FG22-93PC93217 |
Other Number(s) | JCTLA5; ISSN 0021-9517 |
Resource Type | Journal Article |
Resource Relation | Journal of Catalysis ; VOL. 164 ; ISSUE: 1 ; PBD: Nov 1996 |
Subject | 33 ADVANCED PROPULSION SYSTEMS ;20 FOSSIL-FUELED POWER PLANTS ;40 CHEMISTRY ;54 ENVIRONMENTAL SCIENCES ; IRON OXIDES; CATALYTIC EFFECTS; CHROMIUM OXIDES; TITANIUM OXIDES; CLAYS; NITRIC OXIDE; SELECTIVE CATALYTIC REDUCTION; AMMONIA; OXIDATION; CATALYST SUPPORTS; CATALYSTS; TEMPERATURE DEPENDENCE; ABSORPTION SPECTROSCOPY; HETEROGENEOUS CATALYSIS; SURFACE AREA; BROENSTED ACIDS; LEWIS ACIDS |
Description/Abstract | TiO{sub 2}-pillard clay (PILC) with high surface area, large pore volume, and large interlayer spacing was used as the support for mixed Fe{sub 2}O{sub 3} and Cr{sub 2}O{sub 3} as the catalyst for selective catalytic reduction (SCR) of NO with NH{sub 3}. The Fe/Cr ratio was varied at a fixed total amount of oxide dopant of 10% (wt). The Fe-Cr/TiO{sub 2}-PILC with Fe/Cr=3 showed the highest activity. Compared with commercial V{sub 2}O{sub 5}/TiO{sub 2} catalysts, the activity (on a per gram basis) of the doped pillared clay was approximately twice as high under H{sub 2}O- and SO{sub 2}-free conditions and was approximately 40% higher under conditions with H{sub 2}O and SO{sub 2}. In addition, its activity for SO{sub 2} oxidation was only 20%-25% of that of the V{sub 2}O{sub 5}-based catalysts. TPD of NH{sub 3} on the Fe-Cr/TiO{sub 2}-PILC catalyst showed that both M=O and M-OH (M=Fe or Cr) were necessary for the SCR reaction. In situ IR spectra of NH{sub 3} showed that there was a higher Bronsted acidity than the Lewis acidity on the surface under reaction conditions and that there existed a direct correlation between the SCR activity and the Bronsted acidity among pillared clays with different Fe/Cr ratios. These results, along with the transient response to O{sub 2}, indicated that a similar mechanism to that on the V{sub 2}O{sub 5} catalyst was operative. The TiO{sub 2}-pillared clay used as the support also contributed to the high activity of the Fe-Cr catalyst. The TiO{sub 2} pillars combined with the tetrahedral SiO{sub 2} surfaces of the clay apparently gave rise to a high dispersion of Fe{sub 2}O{sub 3}. 52 refs., 10 figs., 5 tabs. |
Country of Publication | United States |
Language | English |
Format | pp. 70-81 ; PL: |
System Entry Date | 2001 May 05 |
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