In situ FT-IR study of Rh-Al-MCM-41 catalyst for the selective catalytic reduction of nitric oxide with propylene in the presence of excess oxygen
- Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Chemical Engineering
Rh-exchanged Al-MCM-41 is studied for selective catalytic reduction (SCR) of NO by C{sub 3}H{sub 6} in the presence of excess oxygen. It shows a high activity in converting NO to N{sub 2} and N{sub 2}O at low temperatures. In situ FT-IR studies indicate that Rh-NO{sup +} species (1910--1898 cm{sup {minus}1}) is formed on the Rh-Al-MCM-41 catalyst in flowing NO/He, NO + O{sub 2}/He and NO + C{sub 3}H{sub 6} + O{sub 2}/He at 100--350 C. This species is quite active in reacting with propylene and/or propylene adspecies (e.g., {pi}-C{sub 3}H{sub 5}, polyene, etc.) at 250 C in the presence/absence of oxygen, leading to the formation of the isocyanate species (Rh-NCO, at 2174 cm{sup {minus}1}), CO, and CO{sub 2}. Rh-NCO is also detected under reaction conditions. A possible reaction pathway for reduction of NO by C{sub 3}H{sub 6} is proposed. In the SCR reaction, Rh-NO{sup +} and propylene adspecies react to generate the Rh-NCO species, then Rh-NCO reacts with O{sub 2}, NO, and NO{sub 2} to produce N{sub 2}, N{sub 2}O, and CO{sub 2}. Rh-NO{sup +} and Rh-NCO species are two main intermediates for the SCR reaction on Rh-Al-MCM-41 catalyst.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG22-96PC96206
- OSTI ID:
- 349863
- Journal Information:
- Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Vol. 103, Issue 12; Other Information: PBD: 25 Mar 1999
- Country of Publication:
- United States
- Language:
- English
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