Study of the NOχ reaction with reducing gases on Fe/ZrO2 catalyst |
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Authors: | Eugenio Guglielminotti Flora Boccuzzi |
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Affiliation: | Dipartimento Chimica Inorganica, Chimica Fisica e Chimica dei Materiali, Universitàdi Torino, Via P. Giuria 7, 10125 Torino ,Italy |
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Abstract: | The Fe/ZrO2 catalyst (1% Fe by weight) shows a strong adsorption capacity toward the nitric oxide (at room temperature the ratio NOFe is ca. 0.5) as a consequence of the formation of a highly dispersed iron phase after reduction at 500–773 K. Nitric oxide is adsorbed mainly as nitrosyl species on the reduced surface where the Fe2+ sites are prevailing, but it is easily oxidised by oxygen forming nitrito and nitrato species adsorbed on the support. However, in the presence of a reducing gas such as hydrogen, carbon monoxide, propane and ammonia at 473–573 K the Fe-nitrosyl species react producing nitrogen, nitrous oxide, carbon dioxide and water, as detected by FTIR and mass spectrometers. The results show that nitric oxide reduction is more facile with hydrogen containing molecules than with CO, probably due the co-operation of spillover effects. Experiments carried out with the same gases in the presence of oxygen show, however, a reduced dissociative activity of the surface iron sites toward the species NOχ formed by NO oxidation and therefore the reactivity is shifted to higher temperatures. |
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Keywords: | Ammonia Carbon monoxide Hydrogen Iron/zirconia Nitric oxide reduction Propane |
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