Small‐pore zeolites such as chabazite (CHA) are excellent candidates for the selective separation of CO₂; however, the current synthesis involves several steps and the use of organic structure‐directing agent (OSDA), increasing their cost and energy requirements. We report the synthesis of small‐pore zeolite crystals (aluminosilicate) with CHA‐type framework structure by direct synthesis in a colloidal suspension containing a mixture of inorganic cations only (Na⁺, K⁺, and Cs⁺). The location of CO₂ molecules in the host structure was revealed by 3D electron diffraction (3D ED). The high sorption capacity for CO₂ (3.8 mmol g⁻¹ at 121 kPa), structural stability and regenerability of the discreate CHA zeolite nanocrystals is maintained for 10 consecutive cycles without any visible degradation. The CHA zeolite (Si:Al=2) reaches an almost perfect CO₂ storage capacity (8 CO₂ per unit cell) and high selectivity (no CH₄ was adsorbed).

中文翻译：

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不具有用于选择性捕获CO2的有机模板的离散CHA沸石纳米晶体的合成。

小孔沸石，如菱沸石（CHA）是选择性分离CO _2的极佳候选材料；然而，目前的合成涉及多个步骤，并使用了有机结构导向剂（OSDA），这增加了其成本和能源需求。我们报告了通过在仅包含无机阳离子（Na ⁺，K ⁺和Cs ⁺）混合物的胶体悬浮液中直接合成，可以合成具有CHA型骨架结构的小孔沸石晶体（铝硅酸盐）。通过3D电子衍射（3D ED）揭示了主体结构中CO ₂分子的位置。对CO ₂的高吸附容量（3.8 mmol g ^-1在121kPa）下，残存的CHA沸石纳米晶体的结构稳定性和可再生性连续10个循环而没有任何可见的降解。CHA沸石（Si：Al = 2）达到了几乎完美的CO ₂储存容量（每单位晶胞8个CO ₂）和高选择性（没有CH ₄吸附）。