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N2O Formation Mechanism During Low-Temperature NH3-SCR over Cu-SSZ-13 Catalysts with Different Cu Loadings
Industrial & Engineering Chemistry Research ( IF 3.8 ) Pub Date : 2021-07-12 , DOI: 10.1021/acs.iecr.1c01514
Dongwei Yao 1 , Biao Liu 1 , Feng Wu 1 , Yuxi Li 1 , Xiaohan Hu 1 , Weiyang Jin 2 , Xinlei Wang 3
Affiliation  

Based on the in situ DRIFTS studies, the mechanism of formation and decomposition of NH4NO3 (decomposition to N2O) over Cu-SSZ-13 with different Cu loadings was investigated. Under standard SCR conditions, NH4NO2 can form over all catalysts, which can be more easily oxidized to NH4NO3 over higher Cu content catalysts because of their stronger oxidative ability resulting from the elevation of Cu(OH)+. Hence, a higher Cu content leads to more low-temperature N2O formation, while N2O barely occurred over Cu-0 and Cu-0.7 catalysts. When NO2 exists, NO3 forms from the disproportionation reaction of NO2 first, then reacts with NH3 to form NH4NO3, leading to N2O formation over all catalysts. Nevertheless, Cu2+ is active for the reaction between NH4NO3 and NO. The increase of Cu2+ allows more NH4NO3 consumption, and the self-inhibition of NH4NO3 alleviates, which allows NH4NO3 to decompose to N2O at lower temperatures, and N2O formation peak shifts toward lower temperatures.

中文翻译:

不同Cu负载量的Cu-SSZ-13催化剂在低温NH 3 -SCR过程中N 2 O的形成机制

基于原位DRIFTS研究,研究了不同Cu负载量的Cu-SSZ-13上NH 4 NO 3 (分解为N 2 O)的形成和分解机制。在标准 SCR 条件下,NH 4 NO 2可以在所有催化剂上形成,由于 Cu(OH) +升高导致其氧化能力更强,因此在更高 Cu 含量的催化剂上更容易氧化为 NH 4 NO 3。因此,较高的Cu含量导致更多的低温N 2 O形成,而N 2 O在Cu-0和Cu-0.7催化剂上几乎不发生。当 NO 2存在时,NO3 首先由 NO 2的歧化反应形成,然后与 NH 3反应形成 NH 4 NO 3,导致在所有催化剂上形成N 2 O。然而,Cu 2+对NH 4 NO 3和NO之间的反应具有活性。Cu的增加2+允许更多的NH 4 NO 3的消耗,和NH的自抑制4 NO 3的缓解,这允许NH 4 NO 3以分解成N 2在较低温度下O,和N 2O 形成峰向较低温度移动。
更新日期:2021-07-21
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