Exploring Organic Structure-directing Agents Used for SAPO-34 to Synthesize SSZ-13
Exploring Organic Structure-directing Agents Used for SAPO-34 to Synthesize SSZ-13
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DOI：
10.7503/cjcu20200855
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Liu Zhongmin
中科院分区：
文献类型：
--
作者：
Wang Lei;Sun Tantan;Yan Nana;Ma Chao;Liu Xiaona;Tian Peng;Guo Peng;Liu Zhongmin
The aluminosilicate zeolite SSZ-13 and zeolitic silicoaluminophosphate molecular sieve(SAPO MS)SAPO-34 have been widely used in commercialized catalytic applications,such as the methanol-to-olefins (MTO)process and the selective catalytic reduction of NO_x with NH_3(NH_3-SCR). Nowadays,a variety of commercialized organic structure-directing agents(OSDAs)have been utilized for preparing SAPO-34,while the OSDAs for synthesizing SSZ-13 still mainly relies on the classical N,N,N-trimethyladamantammonium hydroxide(TMAdaOH). Therefore,it is of great significance to seek for the suitable OSDAs,which can direct the synthesis of SSZ-13 with higher cost performance and appliable high silicon-to-alumina ratio(SAR). Herein,three OSDAs used for preparing SAPO-34[diisopropylamine(DIPA),dipropylamine(DPA)and n-butylamine(nBA)]were successfully employed for synthesizing SSZ-13 by partial replacing the expensive TMAdaOH with or without the assistance of seeds. Systemic investigation focused on SSZ-13 preparation was explored by powder X-ray diffraction(PXRD)and solid-state nuclear magnetic resonance(ss-NMR)analyses. As a result,the as-synthesized SSZ-13 zeolites possess a tunable range of SARs(11―22)and Cu-SSZ-13 catalysts show excellent NH_3-SCR performance compared with commercialized ones. The crystallization mechanism of SSZ-13 synthesized by DIPA and TMAdaOH were also studied and the addition of DIPA would accelerate the crystallization process,improve the yields,and prevent the formation of amorphous phase. The work presented here might provide new insights for identifying more efficient and commercialized OSDAs for preparing SSZ-13 with tailored properties.
