posted on 2021-10-12, 21:04authored byNicholas A. Jose, Jithin John Varghese, Samir H. Mushrif, Hua Chun Zeng, Alexei A. Lapkin
Due
to their high anisotropy and tunable chemical composition,
two-dimensional metal organic frameworks (2D MOFs) have great potential
as building blocks for next-generation materials in a diverse range
of applicationsfrom electrochemical catalysis to membrane
separation. However, the controllable synthesis is complicated by
the environment–surface interactions that arise from the high
anisotropy, thinness, and functionally diverse surfaces of 2D MOFs.
Liquid cell transmission electron microscopy (LCTEM) offers a unique
opportunity to study these interactions in situ.
In this work, we analyzed the effects of different solvent environments
on the structure and aggregation dynamics of copper benzene dicarboxylic
acid (CuBDC) nanosheets, which were synthesized using a high shear
annular microreactor. LCTEM revealed that 2D MOF nanosheets undergo
oriented attachment and that the rate and direction of oriented attachment
is controlled by solvent–surface interactions. We investigated
the nature of these solvent interactions using density functional
theory calculations, which suggest that the binding energy of solvents
to different MOF surfaces is likely responsible for this behavior.
The CuBDC nanosheets were then applied as adsorbents in organic solvents,
in which we showed how solvent-mediated oriented attachment could
significantly affect adsorption properties.