Computer-assistance allows selecting the most adequate low-cost organic structure directing agents (OSDAs) for the crystallization of Al-rich CHA-type zeolites. The host-guest stabilization energies of tetraethylammonium (TEA), methyltriethylammonium (MTEA) and dimethyldiethylammonium (DMDEA), in combination with Na, were first theoretically evaluated. This “ab-initio” analysis reveals that two TEA show a serious steric hindrance in a cha cavity, whereas two MTEA would present excellent host-guest confinements. The synthesis of Al-rich CHA-type zeolites has been accomplished using TEA and MTEA. Electron diffraction and high-resolution transmission electron microscopy reveal large CHA-domains with narrow faulted GME-domains in the CHA-type material synthesized with TEA, confirming the better OSDA-directing roles of MTEA cations towards the cha cavity, in good agreement with DFT calculations. Cu-exchanged Al-rich CHA-type samples achieved with MTEA and TEA show excellent catalytic activity and hydrothermal stability for the selective catalytic reduction (SCR) of NOx with ammonia under conditions relevant for future heavy duty diesel conditions.

计算机辅助可以选择最合适的低成本有机结构导向剂 (OSDA)，用于富铝 CHA 型沸石的结晶。首先从理论上评估了四乙基铵 (TEA)、甲基三乙基铵 (MTEA) 和二甲基二乙基铵 (DMDEA) 与 Na 结合的主客体稳定能。这种“从头开始”的分析表明，两种 TEA 在cha 中表现出严重的位阻腔，而两个 MTEA 将提供出色的主客限制。已经使用 TEA 和 MTEA 完成了富铝 CHA 型沸石的合成。电子衍射和高分辨率透射电子显微镜显示，在用 TEA 合成的 CHA 型材料中存在具有窄断层 GME 域的大 CHA 域，证实了 MTEA 阳离子对cha腔的更好的 OSDA 导向作用，与 DFT 一致计算。用 MTEA 和 TEA 获得的富铜交换的富铝 CHA 型样品在与未来重型柴油机条件相关的条件下，用氨选择性催化还原 (SCR) 显示出优异的催化活性和水热稳定性。