锡原子插入MFI结构分子筛骨架位置的判据
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- 英文论文题名：Evidence of the Incorporation of Sn Atoms into the Framework of MFI-type Zeolite
- 论文作者：鞠龙 ; 夏长久 ; 彭欣欣 ; 林民 ; 朱斌 ; 舒兴田
- 英文论文作者：Long Ju ; Changjiu Xia ; Xinxin Peng ; Min Lin ; Bin Zhu ; Xingtian Shu ; State Key Laboratory of Catalytic Materials and Reaction Engineering ; Research Institute of Petroleum Processing ; SINOPEC
- 年：2016
- 作者机构：中国石化石油化工科学研究院石油化工催化材料与反应工程国家重点实验室;
- 论文关键词：Sn-MFI分子筛 ; 物化表征 ; 锡原子 ; 进入骨架
- 会议召开时间：2016-07-01
- 会议录名称：中国化学会第30届学术年会摘要集-第三十二分会： 多孔功能材料
- 语种：中文
- 分类号：O643.36
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第三十二分会 ; 多孔功能材料
- 会议地点：中国辽宁大连
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：1
- 文件大小：158k
- 原文格式：D
- 会议级别：全国
摘要
近年来,Sn-MFI的合成及其催化的含氧烃的转化反应已经成为研究热点。四配位骨架锡物种是Sn-MFI分子筛的活性中心,因此确定Sn原子是否插入骨架对拓宽其催化应用具有重要意义。XRD Rietveld结构精修结果表明Sn-MFI的"五指峰"位置随着锡硅比增加而向小角度偏移,这是由于锡原子插入MFI结构使得晶胞膨胀,使晶胞的层间距增大。Sn-MFI分子筛在FT-IR中960 cm-1处存在吸收峰,证明了Sn-O-Si键的不对称振动。UV-Vis谱中210 nm吸收峰归属于四配位的骨架锡物种,230-350 nm处的宽峰归属为五配位或者六配位的锡物种。XPS表征表明Sn-MFI的电子结合能较SnO_2向增大,这是因为锡原子进入骨架后形成Si-O-Sn键。~(29)Si MAS NMR结果表明,锡原子的插入导致了-116ppm处肩峰的产生,这是骨架锡原子对骨架硅物种的诱导效应所致。TEM和HRTEM表明,分子筛由小晶粒堆叠而成;且分子筛的晶粒无明显的Sn粒子聚集(如Fig.1b),表明Sn原子高分散插入到了分子筛骨架位置。
Recently,the synthesis of Sn-MFI zeolite and its catalytic application in oxygenated hydrocarbons conversion have been a hot spot in chemistry.As tetrahedral framework Sn species are active sites,thus it is important to confirm the Sn incorporation,for extending its application region.The characteristic peaks of Sn-MFI slightly move to lower 2θ with the increasing of Sn/Si ratio,owing to the swelling of unit cell by Sn incorporation.The peaks at 960cm~(-1)in FTIR and 210 nm in UV-Vis are considered as the evidence of Sn incorporation into framework sites.Interestingly,Sn-MFI shows higher binding energy than SnO_2 in XPS spectra,indicating the formation Sn-O-Si bonds.It agrees well with the Si(OSi)_3(OSn)_1 species assigned by ~(29)Si MAS NMR at-116 ppm.Moreover,no Sn-rich nanoparticles are detected in HRTEM image,which means the Sn atoms are highly dispersed in the bulk crystal.Consequently,the incorporation of Sn atoms has been confirmed.
Recently,the synthesis of Sn-MFI zeolite and its catalytic application in oxygenated hydrocarbons conversion have been a hot spot in chemistry.As tetrahedral framework Sn species are active sites,thus it is important to confirm the Sn incorporation,for extending its application region.The characteristic peaks of Sn-MFI slightly move to lower 2θ with the increasing of Sn/Si ratio,owing to the swelling of unit cell by Sn incorporation.The peaks at 960cm~(-1)in FTIR and 210 nm in UV-Vis are considered as the evidence of Sn incorporation into framework sites.Interestingly,Sn-MFI shows higher binding energy than SnO_2 in XPS spectra,indicating the formation Sn-O-Si bonds.It agrees well with the Si(OSi)_3(OSn)_1 species assigned by ~(29)Si MAS NMR at-116 ppm.Moreover,no Sn-rich nanoparticles are detected in HRTEM image,which means the Sn atoms are highly dispersed in the bulk crystal.Consequently,the incorporation of Sn atoms has been confirmed.
引文
[1]Fejes,P.;Nagy,J.,Kovács,K.,Vankó,G.Appl.Catal.A-Gen.1996,145:155.
[2]Cho,H.J.;Dornath,P.;Fan,W.ACS Catal.2014,4:2029.
[2]Cho,H.J.;Dornath,P.;Fan,W.ACS Catal.2014,4:2029.