Boosting the low-temperature activity of Cu-SSZ-13 for NH3-SCR by mixing MnCeTiOx: The effect of nitrates on Cu redox cycle
Boosting the low-temperature activity of Cu-SSZ-13 for NH3-SCR by mixing MnCeTiOx: The effect of nitrates on Cu redox cycle
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DOI：
10.1016/j.jece.2022.109016
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发表时间：
2022-11
影响因子：
7.7
通讯作者：
Xinyu Li;Huawang Zhao;Yating Huang;Xiaomin Wu;Zhiwei Huang;Huazhen Shen;Guohua Jing
中科院分区：
文献类型：
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作者：
Xinyu Li;Huawang Zhao;Yating Huang;Xiaomin Wu;Zhiwei Huang;Huazhen Shen;Guohua Jing
将Cu-SSZ-13与MnCeTiO_x机械混合制备复合催化剂，以提高氨选择性催化还原（SCR）NOx的性能。复合催化剂中Cu-SSZ-13和MnCeTiOx组分的最佳质量比为1：1，在150-300 °C温度范围内，NOx转化率比单独使用Cu-SSZ-13时提高了40%左右。MnCeTiO_x对NO的活化能力明显强于Cu-SSZ-13。红外光谱（IR）和密度泛函理论（DFT）结果表明，MnCeTiO x上的活性硝酸盐中间体可能迁移到Cu-SSZ-13上，协助单个Cu+氧化为Cu 2+，完成Cu的氧化还原循环。这避免了Cu-SSZ-13低温SCR中Cu+二聚体的形成和氧化的速率决定步骤。研究结果对合理设计低温高性能SCR催化剂具有一定的指导意义。
A composite catalyst was prepared by mechanically mixing Cu-SSZ-13 and MnCeTiOxto improve selective catalytic reduction (SCR) of NOxby ammonia. The optimal mass ratio of Cu-SSZ-13 and MnCeTiOxcomponents in the composite catalysts was 1:1, where the NOxconversion was improved by around 40% in the temperature range of 150–300 °C compared with Cu-SSZ-13 alone. MnCeTiOxpresented significantly stronger ability on the activation of NO to nitrates species than Cu-SSZ-13. Infrared (IR) and density functional theory (DFT) results showed that active nitrates intermediate on MnCeTiOxmight migrate to Cu-SSZ-13, which assisted the oxidation of single Cu+to Cu2+to complete the Cu redox cycle. This avoided the rate-determining step that formation and oxidation of Cu+dimers in low-temperature SCR over Cu-SSZ-13. The research results are beneficial to the rational design of SCR catalysts with high-performance at low temperatures.