Transition metals modified commercial SCR catalysts as efficient catalysts in NH3-SCO and NH3-SCR reactions

Different transition metals were used to modify commercial V2O5-WO3-TiO2 catalysts to remove slip ammonia and residual NOx from the tail of SCR system. The performance of selective catalytic oxidation of NH3 (NH3-SCO) and selective catalytic reduction of NO by NH3 (NH3-SCR) of different catalysts at 150-400 ℃ was studied. The results showed that the loading of transition metals could significantly improve the NH3 oxidation ability of the catalysts, and the presence of NO furtherly promoted it. Cu-SCR catalyst obtained the best activity of both NH3 oxidation and NOx reduction at 350 ℃, and had excellent SO2 and H2O resistance in the presence of NO. The characterization results indicated that the transition metals enhanced the amounts of acid sites and redox ability of the catalysts. Moreover, the transition metals could increase the active oxygen and improve the catalytic performance of the catalysts by the redox reaction with V4+/V5+.