Reduction of Nitric Oxide with Ammonia

Reduction of Nitric Oxide with Ammonia. - Control of the emission of NO from stationary sources is possible by selective catalytic reduction, for which up to now NH3 is the only effective reductant in the presence of excess 02. Beside noble metal catalysts Bauerle etal.101 109 and Wu and Nobe108 studied Al2 03-supported vanadium oxide and found this to be highly effective in NO removal which is considerably enhanced by the presence of 02. Alkali metal compounds which are usually added as promoters for S02 oxidation completely inactivate the catalysts for NO reduction. Adsorption kinetic studies indicated first-order dependence on NH3 adsorption. Similar results were obtained for NO on reduced vanadium oxide, but its adsorption on 

V205 was not measurable. Finally it was observed that these catalysts were very resistant to S02. 

Yoshida et a/.110 concluded from experiments with copper vanadate that the NO reduction on a pre-reduced catalyst proceeds by a mechanism involving adsorbed NO, adsorbed NH3, and adsorbed 02. Shikada et al.nl have shown that by using a complex Si02 —Ti02 oxide as carrier a very active and stable catalyst is obtained which is highly resistant to S02 for long periods. 

A MO investigation of Miyamoto et al.113 also supports the proposed mechanism. The calculations show NH3 to be stably adsorbed on a Br nsted acid site whereas NO is hardly adsorbed at all. The calculations show that electrons of the adsorbed NH3 are transferred to the antibonding orbitals of NO leading to its dissociation. 

Finally Miyamoto et al. again confirmed this mechanism in a kinetic study using the pulse reaction technique.114 

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The mechanism of the selective reduction of nitric oxide with ammonia in the... 

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S. Kasaoka, E. Sasaoka, and H. Nanba, "Deactivation Mechanism of Vanadium Pentoxide-Titanium Dioxide Catalyst by Deposited Alkali Salts and Regeneration Method of Deactivated Catalyst in Reduction of Nitric Oxide with Ammonia", Nippon Kagaku Kaishi. Japan, 1984,3, 486-494. 

A. Baiker, P. Dollenmeier, and M. Glinski, "Selective Catalytic Reduction of Nitric Oxide with Ammonia." 1. and II, Appl. Catal.. 1987,2S, 351-364 and 365-380. 

Julie Doherty, MSc thesis, UCD, Selective Catalytic Reductions of Nitric Oxide with Ammonia and Urea over Copper and Iron-based catalysts, 2004. 

Seiyama T, Arakawa T, Matsuda T et al (1977) Catalytic activity of transition metal ion exchanged Y zeolites in the reduction of nitric oxide with ammonia. Journal of Catalysis 48 1-7... 

Komatsu T, Nunokawa M, Moon IS et al (1994) Kinetic Studies of Reduction of Nitric Oxide with Ammonia on Cu -Exchanged Zeolites. Journal of Catalysis 148 427-437... 

Qi G, Wang Y, Yang R T (2008) Selective catalytic reduction of nitric oxide with ammonia over ZSM-5 based catalysts for diesel engine application. Catal. Lett. 121 111-117. 

Qi G, Yang R T (2005) Ultra-activity Fe/ZSM-5 catalysts for selective catalytic reduction of nitric oxide with ammonia. Appl. Catal. B 60 13-22. 

Delahay G, Valade D, Guzman-Vargas A, Coq B (2005) Selective catalytic reduction of nitric oxide with ammonia on Fe-ZSM-5 catalysts prepared by different methods. Appl. 

Singoredjjo L, Korver R, Kapteijn, Mounlijn J (1992) Alumina supported manganese oxides for the low-temperature selective catalytic reduction of nitric oxide with ammonia. AppL... 

Baiker A, Dollenmeier P, Glinski M, Reller A (1987) Selective catalytic reduction of nitric oxide with ammonia I. Monolayer and Mulitlayers of Vanadia Supported on Titania. Appl... 

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The Pd +Cu )-catalysed reduction of nitric oxide by carbon monoxide (i.e., C0 + 2N0 C02+N20), which takes place in hydrochloric acid is believed to involve a Cu -Pd -NO species. The catalytic reduction of nitric oxide with ammonia by aqueous [Cu(NH3)4] + has been compared with those in which a Y-type zeolite was employed as a support. ... 

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