Role of Brønsted acidity in NH3 selective catalytic reduction reaction on Cu/SAPO-34 catalysts
Role of Brønsted acidity in NH3 selective catalytic reduction reaction on Cu/SAPO-34 catalysts
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DOI：
10.1016/j.jcat.2015.01.011
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发表时间：
2013-06
影响因子：
7.3
通讯作者：
Lei Wang;Wei Li;S. J. Schmieg;D. Weng
中科院分区：
文献类型：
--
作者：
Lei Wang;Wei Li;S. J. Schmieg;D. Weng
本文采用钾离子交换法制备了一系列具有不同Brønsted酸中心的Cu/SAPO-34催化剂，考察了Brønsted酸在NH3-SCR反应中的作用。研究了钾对Cu/SAPO-34催化剂结构和酸性的影响。在钾的存在下，未观察到SAPO-34结构和铜物种的显著变化。随着钾负载量的增加，Cu-K/SAPO-34催化剂的NH3-SCR活性随着Brønsted酸性的降低而降低。采用红外光谱法建立了Cu-（K）/SAPO-34分子筛中Brønsted酸中心的定量方法，并通过酸中心生成机理和NH3-TPD结果进行了验证。用DRIFTS法测定的溴化羟基量与NH3-TPD高温脱附的NH3量呈线性关系。
In the present work, a series of Cu/SAPO-34 catalysts with varying number of Brønsted acid sites has been prepared by ion exchanging with potassium to investigate the role of Brønsted acidity in the NH3-SCR reaction. The impact of potassium on the structural and acidic properties of Cu/SAPO-34 catalysts has been studied. No significant changes in both the SAPO-34 structure and the copper species were observed in the presence of potassium. With increasing potassium loading, the NH3-SCR activity of the Cu-K/SAPO-34 catalysts decreased in accordance with the decreasing Brønsted acidity. The quantification method of Brønsted acid sites in the Cu-(K)/SAPO-34 was developed by using IR spectroscopy, which was confirmed by acid site generation mechanism and NH3-TPD results. A linear relationship was found between the amounts of Brønsted OH groups determined by DRIFTS and the NH3desorbed at high temperatures from NH3-TPD.