Abstract
Background: V2O5–WO3(MoO3)/TiO2 catalyst, as the core of selective catalytic reduction of NO with NH3 (SCR) has some drawbacks, such as high working temperature window (300- 400°C), toxicity of V-based catalyst and so on. Therefore, the development of the catalyst with better low temperature denitration activity and weaker toxicity are necessary.
Objective: The study aimed at the development of highly dispersed MnOx/CNTs catalysts with excellent denitration activity at 80-180°C, and weaker toxicity of MnOx. It is worth noting that an in-situ precipitation method based on the reaction of manganese acetate and sodium carbonate, is advantageous for the in-situ deposition of the active component, and the catalytic activity.
Methods: MnOx/CNTs catalysts with different Mn/C molar ratios were fabricated by in-situ precipitation method due to the reaction of manganese acetate and sodium carbonate. The microstructure, crystalline property, the content of the surface element, valence state, redox property, and catalytic activity were confirmed by FESEM, TEM, XRD, XPS, TPD, and fixed-bed reactor.
Results: The as-prepared MnOx/CNTs catalysts exhibited outstanding low temperature SCR activity. The NO conversion of the optimum 1.2% MnOx/CNTs catalyst reached 57.4-89.2% at 80-180oC, which resulted from the amorphous MnOx catalysts, having a higher ratio of Mn4+/Mn3+ and OS/(OS+OL).
Conclusion: MnOx/CNTs catalysts have been prepared by the in-situ precipitation method based on the reaction of manganese acetate and sodium carbonate. The resultant MnOx/CNTs catalysts presented excellent low temperature denitration activity between 80°C and 180°C. Among them, the 1.2% MnOx/CNTs catalyst exhibited the first rate low temperature denitration activity, and the denitration activity reached 57.4-89.2%, which may be due to the presence of the weakly crystalline or amorphous MnOx, having higher ratio of Mn4+/Mn3+ and OS/(OS+OL).
Graphical Abstract
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