Metal–organic
framework (MOF) heterostructures have shown
promising applications in gas adsorption, gas separation, catalysis,
and energy, arising from the synergistic effect of each component.
However, owing to the difficulty in controlling the size, shape, nucleation,
and growth of MOFs, it remains a great challenge to construct MOF
heterostructures with precisely controlled orientation, morphology,
dimensionality, and spatial distribution of each component. Here,
we report a seeded epitaxial growth method to prepare a series of
hierarchical MOF heterostructures by engineering the structures, sizes,
dimensionalities, morphologies, and lattice parameters of both MOF
seeds and the secondary MOFs. In these heterostructures, PCN-222 (also
known as MOF-545) nanorods selectively grow along the major axis of
the ellipsoid-like PCN-608 nanoparticles, on the two end facets of
the hexagonal prism-like NU-1000 nanorods, and on the two basal planes
of the hexagonal PCN-134 nanoplates, while Zr–BTB nanosheets
selectively grow on the six edge facets of PCN-134 nanoplates. The
selective epitaxial growth of MOFs opens the way to synthesize different
hierarchical heterostructures with tunable architectures and dimensionalities,
which could process various promising applications.