Selective catalytic reduction of NO_x with NH₃ over iron-cerium-tungsten mixed oxide catalyst prepared by different methods

Highlights: • Iron-cerium-tungsten mixed oxide catalysts were prepared through three different methods. • The effect of preparation methods on the NH₃-SCR activity and the surface structure properties of catalyst were investigated. • Iron-cerium-tungsten mixed oxide prepared through microwave irradiation assistant critic acid sol-gel shows higher NH₃-SCR activity. - Abstract: A series of magnetic Fe_0.85Ce_0.10W_0.05O_z catalysts were synthesized by three different methods(Co-precipitation(Fe_0.85Ce_0.10W_0.05O_z-CP), Hydrothermal treatment assistant critic acid sol-gel method(Fe_0.85Ce_0.10W_0.05O_z-HT) and Microwave irradiation assistant critic acid sol-gel method(Fe_0.85Ce_0.10W_0.05O_z-MW)), and the catalytic activity was evaluated for selective catalytic reduction of NO with NH₃. The catalyst was characterized by XRD, N₂ adsorption-desorption, XPS, H₂-TPR and NH₃-TPD. Among the tested catalysts, Fe_0.85Ce_0.10W_0.05O_z-MW shows the highest NO_x conversion over per gram in unit time with NO_x conversion of 60.8% at 350 °C under a high gas hourly space velocity of 1,200,000 ml/(g h). Different from Fe_0.85Ce_0.10W_0.05O_z-CP catalyst, there exists a large of iron oxide crystallite(γ-Fe₂O₃ and α-Fe₂O₃) scattered in Fe_0.85Ce_0.10W_0.05O_z catalysts prepared through hydrothermal treatment or microwave irradiation assistant critic acid sol-gel method, and higher iron atomic concentration on their surface. And Fe_0.85Ce_0.10W_0.05O_z-MW shows higher surface absorbed oxygen concentration and better dispersion compared with Fe_0.85Ce_0.10W_0.05O_z-HT catalyst. These features were favorable for the high catalytic performance of NO reduction with NH₃ over Fe_0.85Ce_0.10W_0.05O_z-MW catalyst.