One-step ion-exchange from Na-SSZ-13 to Cu-SSZ-13 for NH3-SCR by adjusting the pH value of Cu-exchange solution: The effect of H+ ions on activity and hydrothermal stability
One-step ion-exchange from Na-SSZ-13 to Cu-SSZ-13 for NH3-SCR by adjusting the pH value of Cu-exchange solution: The effect of H+ ions on activity and hydrothermal stability
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DOI：
10.1016/j.micromeso.2021.111271
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发表时间：
2021-09
影响因子：
5.2
通讯作者：
Huawang Zhao;Guangpeng Yang;Alexander J. Hill;Bing-er Luo;Guohua Jing
中科院分区：
文献类型：
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作者：
Huawang Zhao;Guangpeng Yang;Alexander J. Hill;Bing-er Luo;Guohua Jing
以Na-SSZ-13为原料，通过调节铜盐溶液的pH值，采用一步离子交换法制备了高性能的Cu-SSZ-13。H+浓度对Cu的负载和分布有显著影响。在没有H+存在的情况下，Cu ~（2+）只能以Cu（OH）~+的形式与八元环（8-MR）中的Na ~+交换，这是由于Na ~+离子位于六元环（6-MR）中的空间位阻所致。当H+存在时，发现它与Cu 2+竞争交换Na+并占据Na-SSZ-13中的交换位点。Cu ~（2+）优先于H ~+占据6-MR中相邻的Al位，而H ~+优先于Cu ~（2+）占据8-MR中的离子交换位，导致Cu-SSZ-13一步法中Cu ~（2+）以6-MR配位为主。H+浓度通过控制Cu 2+负载量和分布来影响整体催化活性和水热稳定性。
A one-step ion-exchange method is developed to prepare high-performance Cu-SSZ-13 from Na-SSZ-13, by adjusting pH values of Cu salt solution during Cu-exchange. The H+concentration has a significant influence on the Cu loading and distribution. In the absence of H+, the Cu2+can only exchange the Na+in 8 member rings (8-MR) as Cu(OH)+, due to the steric hindrance of Na+ions located in 6 member rings (6-MR). When H+is present, it is found to compete with Cu2+to exchange the Na+and to occupy the exchange sites in Na-SSZ-13. The Cu2+ions take a priority over H+to occupy the neighboring Al sites in 6-MR, while H+takes precedence over Cu2+to occupy ion-exchange sites in 8-MR, causing that Cu2+coordinated to 6-MR is dominant in Cu-SSZ-13viaone-step method. The H+concentration affects the overall catalytic activity and hydrothermal stability by controlling the Cu2+loading and distribution.