123rd General Meeting of the KCS

Type Poster Presentation
Area Material Chemistry
Room No. Exhibition Hall 2
Time 4월 19일 (금요일) 11:00~12:30
Code MAT.P-440
Subject Scanning Transmission Electron Microscopy of Two-Dimensional Transition Metal dichalcogenide-Molecules Intercalated Nanosheets
Authors Jaemin Seo, Jeunghee Park*, Ik Seon Kwon1,*, In Hye Kwak2,*
Department of Materials Chemistry, Korea University, Korea
1Advanced Materials Chemistry, Korea University, Korea
2Micro Device Engineering / Microdevices, Korea University, Korea
Abstract Two-dimensional layered structures have recently drawn worldwide attention because of their intriguing optical, electrical, and catalytic properties. Molybdenum disulfide (MoS2) and tungsten disulfide (WS2) are considered as the most promising catalysts for water-splitting hydrogen evolution reaction (HER) to replace the expensive Pt. MoS2 and WS2 nanosheet exhibits polymorphic phases such as stable semiconducting 2H (trigonal prismatic) phase, metastable metallic 1T phase, and metastable 1T' (distorted 1T) semi-metallic phase, depending on the synthesis procedure. Many strategies have been developed to maintain the metsable 1T or 1T' phase by controlling its electronic structures. We found that the intercalation of amine molecules is a promising strategy to enhance the stability of 1T' hase MoS2 nanosheets and their HER performance. To directly observe the 1T' phase and the intercalated molecules, high-angle annular dark-field scanning (HAADF) and annular bright-field (ABF) imaging mode in an advanced (spherical) aberration-corrected high-resolution scanning resolution transmission electron microscopy (STEM) was employed. The ABF-STEM image recognizes light atoms such as carbon of intercalated molecules. Electron-energy loss spectroscopy (EELS) across the interlayers was taken to show the elements between the expanded layers.
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