Abstract:
Composite materials consisting of nanoparticles (NPs) encapsulated within metal-organic frameworks (MOFs) have been shown to yield improved catalytic activity and stability over more traditional heterogeneous supports. These composites are typically constructed by growing a shell of MOF around pre-synthesized nanoparticles or impregnation of a MOF with nanoparticles of appropriate size to fit within the framework. However, recent advances have revealed the capability of robust MOFs to support NP formation from precursors installed within the porous structure. In this work, we investigate the extent to which the pore size and structure of the MOF serve as a template to control the size and population distribution of Cu NPs formed inside Zr-MOFs of various topologies. Characterization of these composite materials using in situ synchrotron X-ray scattering and diffraction experiments provides invaluable insight into the templated NP formation. Probing the catalytic function of the resulting composites allows us to draw connections between the size, location, and accessibility of the NPs and their functionality for the gas-phase reduction of acetylene. By establishing structure-property relationships in this way, we can understand the capacity for MOFs to serve as templates that control critical structural factors of MOF/NP composites, enabling the tunable design of targeted materials for further applications.