Catalytic performance of CeO2-NPs and α-MnO2 mixed oxides catalysts for low-temperature NH3-SCR of NO. (August 2022)

• Record Type: Journal Article
• Authors: Wang, Mingming; Ren, Shan; Xing, Xiangdong; Zhou, Yuhan; Yang, Jie; Chen, Lin; Li, Xiaodi
• Is Part Of: Journal of the Energy Institute. Volume 103(2022)
• Page Start: 54
• Page End: 59
• Publication Date: 2022-08
• Subjects: CeO2-NPs -- α-MnO2 -- Low-temperature NH3-SCR -- Catalytic performance; Power (Mechanics) -- Periodicals; Power resources -- Periodicals; Fuel -- Periodicals; 621.04205
• DOI: 10.1016/j.joei.2022.05.011
• Languages: English
• ISSNs: 1743-9671

Abstract

Abstract: CeO2 -NPs and α-MnO2 were prepared separately by hydrothermal method. Then the CeO2 -NPs and α-MnO2 were mixed by impregnation method to prepare Mn4 CeO x and MnCe4 O x catalysts for investigating their SCR catalytic performance. The results indicated that Mn4 CeO x catalyst had a higher catalytic activity at 75–250 °C than that of MnCe4 O x catalyst, and the NO x conversion rate of Mn4 CeO x catalyst reached the highest point at 150 °C, which was nearly 100%. Besides, N2 selectivity of Mn4 CeO x catalyst was always slightly higher than that of MnCe4 O x catalyst in the testing temperature range. H2 -TPR results showed that the redox ability of Mn4 CeO x catalyst was higher than MnCe4 O x, which favored the SCR reaction. Meanwhile, NH3 -TPD analysis revealed that Mn4 CeO x catalyst had higher adsorption peak temperature and stronger surface acidity than that of MnCe4 O x catalyst, which effectively promoted the NH3 adsorption and activation. From XPS results, the relative content of Ce 4+ in Mn4 CeO x catalyst was 83.2%, which was higher than that of MnCe4 O x catalyst, indicating that Mn4 CeO x catalyst could generate more Mn 4+, and thus produce more oxygen vacancies, which promoted the SCR reaction. Finally, a reaction mechanism model for low-temperature SCR over MnCe4 O x and Mn4 CeO x catalysts was proposed. Highlights: Mixed oxides catalysts of CeO2 -NPs and α-MnO2 were prepared by impregnation method first time. Mn4 CeO x catalyst showed superior catalytic activity at low temperature. Mn4 CeO x catalyst had more oxygen vacancies, stronger reduction ability and higher surface acidity. Reaction mechanism model over Mn–Ce mixed oxides catalysts was proposed.