Nature of Cu Species in Cu–SAPO-18 Catalyst for NH3–SCR: Combination of Experiments and DFT Calculations

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• 作者：Yongheng Li ; Jianlin Deng ; Weiyu Song ; Jian Liu ; Zhen Zhao ; Manglai Gao ; Yuechang Wei ; Liang Zhao
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：July 14, 2016
• 年：2016
• 卷：120
• 期：27
• 页码：14669-14680
• 全文大小：664K
• 年卷期：0
• ISSN：1932-7455

文摘

A series of Cu–SAPO-18 catalysts with various Cu loadings were prepared and their catalytic activities were tested for the selective catalytic reduction of NO with NH<sub>3sub>. The catalysts were characterized by means of XRD, N<sub>2sub> adsorption–desorption, TEM, XPS, UV–vis DRS, H<sub>2sub>-TPR, NH<sub>3sub>-TPD and EPR. Isolated Cu<sup>2+sup> ions are confirmed to be the catalytic active sites. Cu-4.42 catalyst exhibits high NO conversion (>80%) at the lowest temperature of 200 °C among all catalysts. It can be attributed to the maximum amount of isolated Cu<sup>2+sup> ions in Cu-4.42 catalyst. DFT calculations show that the isolated Cu ions are located in the pear shaped cavity and exhibit a preference for the neighboring of 6R planes of Cu–SAPO-18. NH<sub>3sub>–SCR mechanism over Cu–SAPO-18 catalyst is elucidated by a combination of in situ DRIFTS technique and DFT calculations, in which the dissociation of NH<sub>3sub> and the oxidation of NO are shown to be key steps in the reaction.