Study on the Mechanism of Low-Temperature Denitrification and H2o+So2 Resistance Performance of Mnceox Catalysts by Regulating Preparation Methods

Abstract

This study prepared MnCeOx catalysts through citric acid sol-gel method (CA), hydrothermal method (HT), and co-precipitation method (CP), and systematically compared the effects of different methods on their low-temperature NH3-SCR denitrification activity and resistance to H₂O/SO₂. Experiments showed that the NOx conversion rate of MnCeOx-CA prepared by CA method reached 84% at 175 oC, significantly higher than other two catalysts. It also maintained a stable conversion rate of 35% under the coexistence of H2O and SO2 for 8 hours at 175 oC. Structural characterization showed that MnCeOx-CA formed a low-crystallinity Mn-O-Ce solid solution due to the strong coordination effect of citric acid and possessed high surface adsorbed oxygen and active metal valence states. NH3-TPD and in situ DRIFTS confirmed that its Brønsted acid sites promote NH3 adsorption activation. This study revealed the differentiated regulation of the preparation methods on the structure, surface properties, and reaction pathways of the catalysts, providing experimental evidence for the design of low-temperature denitrification catalysts.

Keywords: MnCeOx catalyst, Preparation method, NH3-SCR reaction, Low temperature denitrification