Low-temperature NH&lt;sub&gt;3&lt;/sub&gt;-SCR performance and in situ DRIFTS study on zeolite X-supported different crystal phases of MnO&lt;sub&gt;2&lt;/sub&gt; catalysts

Chen, Lin; Ren, Shan; Chen, Tao; Li, Xiaodi; Wang, Mingming; Chen, Zhichao; Liu, Qingcai

doi:10.3390/catal13040682

Low-temperature NH₃-SCR performance and in situ DRIFTS study on zeolite X-supported different crystal phases of MnO₂ catalysts

Chen L, Ren S, Chen T, Li X, Wang M, Chen Z & Liu Q

Citation

Chen, L., Ren, S., Chen, T., Li, X., Wang, M., Chen, Z., & Liu, Q. (2023). Low-temperature NH₃-SCR performance and in situ DRIFTS study on zeolite X-supported different crystal phases of MnO₂ catalysts. Catalysts, 13(4), 682 (15 pp.). https://doi.org/10.3390/catal13040682

Persistent URL https://www.dora.lib4ri.ch/psi/islandora/object/psi:52405

In this study, a series of zeolite-X-supported different crystal phases of MnO₂ (α-MnO₂, β-MnO₂, γ-MnO₂, and σ-MnO₂) catalysts were prepared via a solid-state diffusion method and high-heat treatment method to explore their low-temperature NH₃-SCR performance. All of the catalysts featured typical octahedral zeolite X structures and manganese dioxides species of various crystal types dispersed across the support surface. Throughout the entire temperature range of the reaction, γ-MnO₂/X catalyst had the highest NO conversion. Additionally, β-MnO₂/X, γ-MnO₂/X, and σ-MnO₂/X catalysts had nearly 100% of N₂ selectivity, whereas the α-MnO₂/X catalyst had the lowest N₂ selectivity (about 90%) below 125 °C. Moreover, the γ-MnO₂/X catalyst demonstrated superior acidity capacity and reduction ability compared with the other three catalysts. All the catalysts contained the essential intermediates NH₂NO and NH₄NO₃ species, which are essential to the SCR reaction. More acid sites and nitrate species existed on the γ-MnO₂/X catalyst than on the other catalysts, thereby boosting the SCR reaction.