A cost-effective route has been developed for the synthesis of nano-sized triclinic SAPO-34 zeolite via seed-assisted grinding method using lower dosage of morpholine as the sole template. The synthesis conditions including silica source, silica concentration, crystallization temperature and time were refined to obtain SAPO-34 zeolite with high phase purity and crystallinity. Particularly, seed crystals preactivated by different methods were utilized to induce the synthesis of nano-sized SAPO-34 zeolites in the subsequent study. The resultant SAPO-34 samples were characterized by XRD, SEM, N₂ physisorption and NH₃-TPD techniques. It was found that the introduction of seed crystals activated by mechanical milling for 20 min and chemical etching with 0.0001 M and 0.01 M H₃PO₄ can not only effectively reduce the crystal size of SAPO-34 zeolites from 3–4 μm to 500–800 nm level, but also can modify their texture and acid properties. This nano-sized SAPO-34 catalyst exhibits a remarkably prolonged catalytic lifetime in methanol to olefins (MTO) reaction in comparison to the conventional micron-sized counterpart. Analogous to solvent-free synthesis of zeolites, this seed-assisted grinding synthesis method is simpler, more efficient than conventional hydrothermal synthesis. More importantly, this method provides a new avenue for preparing superior MTO catalyst.

中文翻译：

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种子辅助研磨合成SAPO-34催化剂及其在甲醇制烯烃转化中的催化寿命延长

已经开发了一种经济有效的途径，通过种子辅助研磨方法（使用较低剂量的吗啉作为唯一模板）来合成纳米级三斜晶SAPO-34沸石。对包括二氧化硅来源，二氧化硅浓度，结晶温度和时间在内的合成条件进行了优化，以获得具有高相纯度和结晶度的SAPO-34沸石。特别地，在随后的研究中，通过不同方法预活化的晶种被用于诱导纳米级SAPO-34沸石的合成。通过XRD，SEM，N ₂物理吸附和NH ₃ -TPD技术对所得的SAPO-34样品进行表征。发现通过机械研磨20分钟并用0.0001 M和0.01 MH _3进行化学蚀刻激活的晶种的引入PO ₄不仅可以有效地将SAPO-34沸石的晶体尺寸从3-4μm减少到500-800 nm，而且可以改变其质地和酸性质。与常规的微米级对应物相比，这种纳米级SAPO-34催化剂在甲醇制烯烃（MTO）反应中显示出显着延长的催化寿命。类似于无溶剂合成沸石，这种种子辅助研磨合成方法比常规水热合成更简单，更高效。更重要的是，该方法为制备优良的MTO催化剂提供了新途径。