As a commerical catalyst of high silica CHA zeolite for NH₃-SCR reaction, controllable Al sites in CHA framework for improving catalytic performance are rarely reported. In this work, two organic templates (TMAda⁺ and DMCHA⁺) were employed to prepare aluminosilicate CHA zeolite with similar Si/Al ratios, donated as CHA-T and CHA-D. Detailed characterizations demonstrate that two completely distinguishable crystallization pathways can be identified as the preferential formation of smaller D6R units for CHA-D with DMCHA⁺ and larger 8MRs for CHA-T with TMAda⁺, resulting in spatially closer Al sites in CHA-D than CHA-T. As an interpretation, CHA-D with more paired Al atoms in 6MR generating more hydrothermally stable Cu²⁺-2Z sites contributes to higher activity than CHA-T at 400−550 °C. These results suggest that the crystallization pathways directed by rational choice of organic templates might be responsible for the controllable Al sites in the framework, which is important for designing efficient NH₃-SCR catalysts.

作为用于NH ₃ -SCR反应的高二氧化硅CHA沸石的商业催化剂，CHA骨架中可控的Al位点改善催化性能的报道很少。在这项工作中，两种有机模板（TMAda ⁺和DMCHA ⁺）被雇用于具有相似Si / Al比，捐赠如CHA-T和CHA-d制备的硅铝酸盐沸石CHA。详述表征表明，两个完全区分的结晶途径可以被识别为优先形成较小D6R单位为CHA-d与DMCHA ⁺和更大8MRs为CHA-T与TMAda ⁺，导致CHA-D中的铝位点比CHA-T在空间上更近。作为一种解释，在400-550°C下，具有6MR中更多铝原子配对的CHA-D产生了更多的水热稳定Cu ²⁺ -2Z位点，从而比CHA-T具有更高的活性。这些结果表明，由有机模板的合理选择指导的结晶途径可能是框架中可控的Al位点的原因，这对于设计有效的NH ₃ -SCR催化剂很重要。