A Study on the Offset Deactivation Effect of Potassium and Phosphorus on MnEuO x SCR Catalyst

In this study, a remarkable offset deactivation effect of K and P on MnEuO x SCR catalyst has been found. Experimental results showed that the NO conversion over K−P poisoned catalyst was close to 80 % at 250 °C. Several characterization techniques containing NH 3 ‐TPD, XPS, H 2 ‐TPR, XRD and in situ DRIFT were used to reveal the mechanism of the offset effect. The characterization of NH 3 ‐TPD and H 2 ‐TPR suggested that the introduction of P on MnEuO x ‐K could improve its surface acidity and redox ability. Moreover, the content of chemisorbed oxygen and Mn 4+ were markedly restored under the situation that the toxic elements were coexistent on catalyst surface. The strong interaction between K and P might be the major reason for the offset deactivation effect. More specifically, PO 3 − species were preferentially bonded with the surface potassium species and released MnO 2 active sites poisoned by K. Therefore, the highly active MnO 2 sites might be protected and the catalytic activity could be restored.