Probing surface structure on two-dimensional metal-organic layers to understand suppressed interlayer packing
metal-organic frameworks, metal-organic layers, surface structure, two-dimensional (2D) materials, solvothermal synthesis
Two-dimensional metal-organic layers (MOLs) from alternatively connected benzene-tribenzoate ligands and Zr6(μ3-O)4(μ3-OH)4 or Hf6(μ3-O)4(μ3-OH)4 secondary building units can be prepared in gram scale via solvothermal synthesis. However, the reason why the monolayers did not pack to form thick crystals is unknown. Here we investigated the surface structure of the MOLs by a combination of sum-frequency generation spectroscopy, nanoscale infrared microscopy, atomic force microscopy, aberrationcorrected transmission electron microscopy, and compositional analysis. We found a partial coverage of the monolayer surface by dangling tricarboxylate ligands, which prevent packing of the monolayers. This finding illustrates low-density surface modification as a strategy to prepare new two-dimensional materials with a high percentage of exposed surface.
Tsinghua University Press
Peican Chen,Yi Liu,Xuefu Hu,Xiaolin Liu,En-Ming You,Xudong Qian,Jiawei Chen,Liangping Xiao,Lingyun Cao,Xinxing Peng,Zhongming Zeng,Yibing Jiang,Song-Yuan Ding,Honggang Liao,Zhaohui Wang,Da Zhou,Cheng Wang, Probing surface structure on two-dimensional metal-organic layers to understand suppressed interlayer packing. NanoRes.2020, 13(11): 3151–3156