In,Fe-zeolites: Active and stable catalysts for the SCR of NOx—Kinetics, characterization and deactivation studies

✍ Scribed by Ramiro Serra; M. Julia Vecchietti; Eduardo Miró; Alicia Boix

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 812 KB
• Volume: 133-135
• Category: Article
• ISSN: 0920-5861
• DOI: 10.1016/j.cattod.2007.11.039

✦ Synopsis

In this work, the addition of Fe 2 O 3 to InH-zeolites (ZSM5 and mordenite) is investigated for the selective catalytic reduction of NO x with both methane and butane as reducing agents. When Fe is added to InHMOR and methane is used, the NO x to N 2 conversion increases from 25% to 55% at 20,000 h À1 and 500 8C. An increase is also observed when butane is employed but to a lower extent. The role of Fe could be ascribed to an improvement of the NO to NO 2 reaction rate. The presence of iron oxides also improves durability in the presence of 2% water. The catalyst InFeHMOR undergoes a fast initial inhibition after which a reasonable NO x conversion (25%) remains constant during 125 h. TPR, XRD and LRS characterizations indicate that Fe 2 O 3 and Fe 3 O 4 are the iron species present, while InO + at exchange sites and small amounts of In 2 O 3 are also present. The kinetic plots for the NO x selective catalytic reduction (SCR) with methane with the InFeHMOR catalyst show fractional orders for the NO concentration and ca. first order for methane.