Selective catalytic reduction of NO by C3H8 over CoOx/Al2O3: An investigation of structure–activity relationships

✍ Scribed by Chuanhua He; Martin Paulus; Wei Chu; Josef Find; Julius A. Nickl; Klaus Köhler

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 733 KB
• Volume: 131
• Category: Article
• ISSN: 0920-5861
• DOI: 10.1016/j.cattod.2007.10.024

✦ Synopsis

A series of CoO x /Al 2 O 3 catalysts was prepared, characterized, and applied for the selective catalytic reduction (SCR) of NO by C 3 H 8 . The results of XRD, UV-vis, IR, Far-IR and ESR characterizations of the catalysts suggest that the predominant oxidation state of cobalt species is +2 for the catalysts with low cobalt loading ( 2 mol%) and for the catalysts with 4 mol% cobalt loading prepared by sol-gel and co-precipitation. Co 3 O 4 crystallites or agglomerates are the predominant species in the catalysts with high cobalt loading prepared by incipient wetness impregnation and solid dispersion. An optimized CoO x /Al 2 O 3 catalyst shows high activity in SCR of NO by C 3 H 8 (100% conversion of NO at 723 K, GHSV: 10,000 h À1 ). The activity of the selective catalytic reduction of NO by C 3 H 8 increases with the increase of cobalt-alumina interactions in the catalysts. The influences of cobalt loading and catalyst preparation method on the catalytic performance suggest that tiny CoAl 2 O 4 crystallites highly dispersed on alumina are responsible for the efficient catalytic reduction of NO, whereas Co 3 O 4 crystallites catalyze the combustion of C 3 H 8 only.