E. Guglielminotti et F. Boccuzzi, STUDY OF THE NOX REACTION WITH REDUCING GASES ON FE ZRO2 CATALYST/, Applied catalysis. B, Environmental, 8(4), 1996, pp. 375-390
The Fe/ZrO2 catalyst (1% Fe by weight) shows a strong adsorption capac
ity toward the nitric oxide (at room temperature the ratio NO/Fe is ca
. 0.5) as a consequence of the formation of a highly dispersed iron ph
ase after reduction at 500-773 K. Nitric oxide is adsorbed mainly as n
itrosyl species on the reduced surface where the Fe2+ sites are prevai
ling, but it is easily oxidised by oxygen forming nitrito and nitrate
species adsorbed an the support. However, in the presence of a reducin
g gas such as hydrogen, carbon monoxide, propane and ammonia at 473-57
3 K the Fe-nitrosyl species react producing nitrogen, nitrous oxide, c
arbon dioxide and water, as detected by FTIR and mass spectrometers, T
he results show that nitric oxide reduction is more facile with hydrog
en 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 NOx formed by NO oxidation a
nd therefore the reactivity is shifted to higher temperatures.