Effect of MnO2 crystal types on CeO2@MnO2 oxides catalysts for low-temperature NH3-SCR. Issue 5 (October 2022)

• Record Type: Journal Article
• Authors: Chen, Lin; Ren, Shan; Xing, Xiangdong; Yang, Jie; Li, Jiangling; Yang, Jian; Liu, Qingcai
• Is Part Of: Journal of environmental chemical engineering. Volume 10:Issue 5(2022)
• Publication Date: 2022-10
• Subjects: Different crystal types of MnO2 -- CeO2 -- Low-temperature NH3-SCR -- N2O production; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2022.108239
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: A series of MnO2 (with different crystal types) doping CeO2 catalysts were synthesized by combining hydrothermal method and impregnation method, and the SCR activity and N2 O formation of the catalysts were investigated. The results showed that NO conversion rate of CeO2 @ α-MnO2, CeO2 @ β-MnO2 and CeO2 @ γ-MnO2 catalysts from 75 to 250 °C was always more than 95%, which showed excellent low-temperature NH3 -SCR activity. N2 O amount produced by CeO2 @ α-MnO2, CeO2 @ β-MnO2 and CeO2 @ γ-MnO2 catalysts during denitrification all reduced at 75–125 °C comparing with pure MnO2, and the N2 O in denitration process mainly came from SCR reaction, but not from direct oxidation of NH3 . Besides, the reducibility and acidity of the complex oxides catalyst were improved, which was more beneficial to the reaction of adsorbed NH3 with NO, thus reducing the direct oxidation of adsorbed NH3 by O2 and inhibiting the formation of N2 O. What's more, the effect of Ce and different crystal types of MnO2 also influenced N2 O generation behavior. Moreover, the SCR reaction of CeO2 @ α-MnO2 and CeO2 @ β-MnO2 catalysts mainly followed Eley-Rideal (E-R) mechanism, while CeO2 @ γ-MnO2 catalyst followed Langmuir-Hinshelwood (L-H) mechanism. Graphical Abstract: ga1 Highlights: MnO2 crystal types on CeO2 @MnO2 oxides catalysts were firstly synthesized. Effect of different crystalline MnO2 on CeO2 for catalytic performance was studied. N2 O production in catalyst denitration reaction mainly came from SCR reaction. Reducibility and acidity of bioxide catalysts were improved compared with MnO2 .