Comparison study of Cu Fe Ti and Co Fe Ti oxide catalysts for selective catalytic reduction of NO with NH3 at low temperature.
In this paper, a series of Cu Fe Ti and Co Fe Ti oxide catalysts were prepared by sol gel method. Cu Fe Ti and Co Fe Ti oxide catalysts showed the moderate catalytic activity for selective catalytic reduction (SCR) of NO with NH3 at low temperature. The catalysts with the molar ratio as 4:1:10 (M:Fe:Ti) were selected as the representatives for comparison of reaction properties and H2O resistance, which were denoted as Cu Fe/TiO2 and Co Fe/TiO2 respectively. The characterization results manifested Co Fe/TiO2 owned more adsorption capacity of the reactants and Cu Fe/TiO2 had better redox ability. The in situ DRIFTS experiments indicated that adsorbed NH3 species and nitrate species both exhibited reaction activity for Co Fe/TiO2, while nitric oxide was only be reduced by adsorbed NH3 species through Eley Rideal mechanism for Cu Fe/TiO2 at 150degC. Co Fe/TiO2 exhibited the better resistance to H2O and its temperature window shifted towards the higher temperature in presence of 10vol% H2O, while the SCR activity of Cu Fe/TiO2 was inhibited significantly in the whole temperature range investigated. The suppression of adsorption and activation for NH3 and NOx might be the reasons for the reversible inactivation, which was confirmed by the inhibitation of catalytic activities for separation NH3 and NO oxidation under the wet condition. We speculated that different thermal stability of adsorbed species and redox capacity of catalysts leaded to the different SCR behavior in absence and presence of H2O.
Journal of colloid and interface science