Large-Grain, Oriented, and Thin Zeolite MFI Films from Directly Synthesized Nanosheet Coatings
Large-Grain, Oriented, and Thin Zeolite MFI Films from Directly Synthesized Nanosheet Coatings
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DOI：
10.1021/acs.chemmater.8b01346
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发表时间：
2018-05-22
影响因子：
8.6
通讯作者：
Tsapatsis, Michael
中科院分区：
文献类型：
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作者：
Kim, Donghun;Shete, Meera;Tsapatsis, Michael
直接合成的沸石MFI纳米片是制备大晶粒定向MFI薄膜的重要材料。研究了MFI纳米片在四乙基氢氧化铵（TEAOH）硅溶胶中在硅片上的二次生长，并确定了形成取向良好、互生薄膜的条件。这使得从去除种子的纳米片单层涂层中制造出具有大晶粒尺寸（bbb20 μ m）的薄（类似于300 nm） b取向MFI薄膜成为可能。此外，MFI纳米片的多面和各向异性形状允许在不同的晶体学方向上测量MFI生长，并证实沿c轴（纳米片的横向方向）与b轴（纳米片基平面的垂直方向）相比，无孪晶优先生长，其比例在4到11之间。
Directly synthesized zeolite MFI nanosheets are promising building blocks for MFI thin films with large and oriented grains. The secondary growth of MFI nanosheets on Si wafers in tetraethylammonium hydroxide (TEAOH) silica sols was investigated, and conditions that result in well-oriented and intergrown film microstructure were established. This has enabled the fabrication of thin (similar to 300 nm) b-oriented MFI films with large grain-size (>2 mu m) from seed-removed nanosheet monolayer coatings. Moreover, the faceted and anisotropic shape of MFI nanosheets allowed the measurement of MFI growth in different crystallographic directions and confirmed the twinning-free preferential growth along the c-axis (a lateral direction of the nanosheet), compared to the b-axis (the direction normal to the nanosheet basal plane), with ratios in a range between 4 and 11.