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

Abstract

In this study, a remarkable offset deactivation effect of K and P on MnEuOx 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 NH3‐TPD, XPS, H2‐TPR, XRD and in situ DRIFT were used to reveal the mechanism of the offset effect. The characterization of NH3‐TPD and H2‐TPR suggested that the introduction of P on MnEuOx‐K could improve its surface acidity and redox ability. Moreover, the content of chemisorbed oxygen and Mn4+ 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, PO3− species were preferentially bonded with the surface potassium species and released MnO2 active sites poisoned by K. Therefore, the highly active MnO2 sites might be protected and the catalytic activity could be restored.

Alkali Metal Poisoning and Regeneration of Selective Catalytic Reduction Denitration Catalysts: Recent Advances and Future Perspectives

“…Although SCR denitration technology based on vanadium-based catalysts has been widely applied and possesses good catalytic performance in high-temperature ranges, it still has many shortcomings such as the high conversion of SO 2 to SO 3 , formation of N 2 O at high temperature, poisoning deactivation by alkali metals in the fly ash, high toxicity of vanadium, and relatively expensive raw materials. , Therefore, developing alternative catalysts for commercial vanadium-based SCR catalysts is an important topic in this field. Mn-based catalysts, introduced in this section, have good activities in the low-temperature range (90–180 °C) and are environmentally friendly, which has obtained the widespread interest of scholars .…”

“…Their studies indicated that the changes of the AC (active carbon) structure and the reduction of surface chemisorbed oxygen, NH 3 , and NO adsorption, which resulted from the combined effect of KCl and As 2 O 3 , were responsible for the poisoning deactivation of the Mn–Ce/AC catalyst. Guo et al found a remarkable offset deactivation effect of K and P on the MnEuO x SCR catalyst. The research results showed that the NO conversion of the K–P poisoning catalyst was close to 80%, while the K poisoning catalyst was only 50%.…”

Thulium oxides supported on MnCeTiOX catalysts for low-temperature NH3-SCR of NOX

“…The MCT catalyst and T 0.06 MCT catalyst have three peaks at 334.5 °C, 390 °C and 505.5 °C. These reduction peaks could be attributed to the continuous reduction process of MnO 2 →Mn 2 O 3 →Mn 3 O 4 →MnO [36]. The reduction peak of cerium oxide and thulium oxide could not be found because of the overlap with the reduction peak of manganese oxide [37].…”