Catalytic reduction of nitric oxide over copper. Part II: Influence of sulfur dioxide

• Published in: Journal of molecular catalysis. A, Chemical Chemical, 1996-11, Vol.112 (3), p.459-467
• Main Authors: Lu, H., Pradier, C.-M., Flodström, A.S.
• Format: Article
• Language: English
• Subjects: Catalysis; Catalytic reactions; Chemistry; Copper; Environment; Exact sciences and technology; General and physical chemistry; Isobutene; Nitric oxide reduction; Sulfur dioxide; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; X-ray photoelectron spectroscopy
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/1381-1169(96)00245-2

The influence of sulfur dioxide on the reduction of nitric oxide over copper, in the presence of isobutene and oxygen, has been examined under reducing conditions in the 720 to 820 K temperature range. The catalytic activity of NO conversion was drastically decreased by the presence of a few ppm of SO 2 in the gas phase, and the toxicity of sulfur was reduced when the temperature was increased. The Cu sample was characterized by X-ray photoelectron spectroscopy, at different stages of the reaction. It was demonstrated that sulfur dioxide poisoned NO conversion by hindering the partial oxidation of the hydrocarbon and by occupying the active sites, both factors contributing to a decrease in the surface concentration of the active intermediate (oxygenated product). Two kinds of adsorbed sulfided species, SO 2− 4 and S 2−, were identified on the Cu surface. At the end of the reaction, the catalyst surface was poisoned both by carbon and sulfur species.