L沸石晶间转化快速合成SSZ-13沸石及其中空结构形成机理  

Rapid Synthesis of SSZ-13 Zeolite via Interzeolite Transformation of L Zeolite and Formation Mechanism of Its Hollow Structure

作　　者：张宗洋 李玉平[1] 张若茜 刘宇峰 陈泽 韩丽娜[1] 韩培德[1] ZHANG Zongyang;LI Yuping;ZHANG Ruoxi;LIU Yufeng;CHEN Ze;HAN Lina;HAN Peide(College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学材料科学与工程学院,太原030024

出　　处：《高等学校化学学报》2023年第10期97-106,共10页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:21978195);山西省应用基础研究项目(批准号:201701D121024)资助。

摘　　要：以N,N,N-三甲基-1-金刚烷胺氢氧化物(TMAdaOH)为有机模板,在180℃晶化温度下,通过补加硅源,以低硅铝比L沸石直接转晶合成SSZ-13分子筛.采用XRD,FTIR,SEM,N_2吸附-脱附和HRTEM等表征手段对晶化过程进行了跟踪,发现180℃高温下晶化4.5 h即可获得高结晶度的SSZ-13沸石;且在该实验条件下,晶化过程中晶粒出现了中空现象.进一步结合SEM-EDS表征结果对中空现象的形成机理进行了研究,发现主要是由于在低硅L沸石缓慢降解和SSZ-13快速成核和生长过程中,存在晶粒中间部位较边缘硅铝比高的现象,即晶粒硅铝比分布不均匀.随着晶化时间的延长,富硅的晶核会在碱液作用下选择性脱硅,从而产生中空现象.最后对合成的中空样品进行铜离子交换,测试其对NO_x的NH_(3)选择性催化还原反应的催化性能,并结合NH_(3)程序升温脱附(NH_(3)-TPD)和H_2程序升温还原(H_2-TPR)表征对催化结果进行了分析.Using N,N,N-trimethyl-1-amantamine hydroxide(TMAdaOH)as organic structure directing agents,SSZ-13 zeolite was synthesized by direct conversion of zeolite L with a low SiO_(2)/Al2O_(3) ratio(SAR)by adding additional Si source at 180℃.The crystallization process was tracked by XRD,FTIR,SEM,N2 adsorption-desorption and HRTEM characterization.It was found that the crystallization rate was greatly accelerated at 180℃,and highly crys-talline SSZ-13 was synthesized after 4.5 h of crystallization.At the same time,it was noted that hollow crystals ap-peared during the crystallization process under this experimental condition.The formation mechanism of the hollow-ing structure was further explored by combining with SEM-EDS characterization.It was found that during the process of slow degradation of zeolite L and the simultaneous rapid nucleation and growth of SSZ-13,the SAR in the middle of zeolite crystals was higher than that at the edge,that is,the SAR distribution in the whole crystal was uneven.Silicon-rich crystal nucleus can be selectively desilicated under alkaline conditions,leading to the hollow phenome-non.Finally,the catalytic performance of the hollow samples after copper ion exchange in NH_(3) selective catalytic reduction(NH_(3)-SCR)reaction of NOx was investigated,and the catalytic results were analyzed in combination with the characterization of NH_(3) temperature-programmed desorption(NH_(3)-TPD)and H2 temperature-programmed Chem.J.Chinese Universities,2023,44(10),20230034 reduction(H2-TPR).

关 键 词：SSZ-13沸石 晶间转化 L沸石 中空沸石 NH_(3)选择性催化还原(NH_(3)-SCR)反应 

分 类 号：O611[理学—无机化学] O643[理学—化学] TQ426[化学工程]