Search

The pair distribution function (PDF) is a versatile characterisation tool in materials science, capable of retrieving atom–atom distances on a continuous scale (from a few angstroms to nanometres), without being restricted to crystalline samples. Typically, total scattering experiments are performed using high-energy synchrotron X-rays, neutrons or electrons to achieve a high atomic resolution in a short time. Recently, PDF analysis provides a powerful approach to target current characterisation challenges in the field of metal- and covalent organic frameworks. By identifying molecular interactions on the pore surfaces, tracking complex structural transformations involving disorder states, and elucidating nucleation and growth mechanisms, structural analysis using PDF has provided invaluable insights into these materials. This review article highlights the significance of PDF analysis in advancing our understanding of MOFs and COFs, paving the way for innovative applications and discoveries in porous materials research. [ABSTRACT FROM AUTHOR]

While many photoresponsive metal‒organic frameworks (MOFs) have been reported to date, finding applications in several technologically relevant fields such as photocatalysis, sensors, and light‐emitting devices, significantly scarcer are the reports addressing the relationship between the MOFs emissive features and their crystalline domain size (i.e., micro‐ and nano‐sized materials). Herein, a valuable contribution is offered to this issue which consists of the use of reticular chemistry to prepare a Zr‐MOF featuring spatially separated tetracarboxylated‐functionalized perylenes as ligand. Single crystal X‐ray analysis of such Zr‐MOF revealed the formation of micro‐ and meso‐porous channels. The perylene‐based Zr‐MOF exhibited notable optoelectronic features, including a relatively small optical bandgap of 1.82 eV and emission features different from that of the constituting perylene ligand in the solid state. Additionally, local probe techniques are used to unveil the emission properties of isolated Zr‐MOF crystals. Space‐ and time‐resolved fluorescence studies revealed a strong dependence of the emissive features of the Zr‐MOF, both in terms of its intensity and lifetime, to the crystalline domain size. [ABSTRACT FROM AUTHOR]

Encapsulating ultrasmall Cu nanoparticles inside Zr‐MOFs to form core–shell architecture is very challenging but of interest for CO2 reduction. We report for the first time the incorporation of ultrasmall Cu NCs into a series of benchmark Zr‐MOFs, without Cu NCs aggregation, via a scalable room temperature fabrication approach. The Cu NCs@MOFs core–shell composites show much enhanced reactivity in comparison to the Cu NCs confined in the pore of MOFs, regardless of their very similar intrinsic properties at the atomic level. Moreover, introducing polar groups on the MOF structure can further improve both the catalytic reactivity and selectivity. Mechanistic investigation reveals that the CuI sites located at the interface between Cu NCs and support serve as the active sites and efficiently catalyze CO2 photoreduction. This synergetic effect may pave the way for the design of low‐cost and efficient catalysts for CO2 photoreduction into high‐value chemical feedstock. [ABSTRACT FROM AUTHOR]

Encapsulating ultrasmall Cu nanoparticles inside Zr‐MOFs to form core–shell architecture is very challenging but of interest for CO2 reduction. We report for the first time the incorporation of ultrasmall Cu NCs into a series of benchmark Zr‐MOFs, without Cu NCs aggregation, via a scalable room temperature fabrication approach. The Cu NCs@MOFs core–shell composites show much enhanced reactivity in comparison to the Cu NCs confined in the pore of MOFs, regardless of their very similar intrinsic properties at the atomic level. Moreover, introducing polar groups on the MOF structure can further improve both the catalytic reactivity and selectivity. Mechanistic investigation reveals that the CuI sites located at the interface between Cu NCs and support serve as the active sites and efficiently catalyze CO2 photoreduction. This synergetic effect may pave the way for the design of low‐cost and efficient catalysts for CO2 photoreduction into high‐value chemical feedstock. [ABSTRACT FROM AUTHOR]

Encapsulating ultrasmall Cu nanoparticles inside Zr‐MOFs to form core–shell architecture is very challenging but of interest for CO2 reduction. We report for the first time the incorporation of ultrasmall Cu NCs into a series of benchmark Zr‐MOFs, without Cu NCs aggregation, via a scalable room temperature fabrication approach. The Cu NCs@MOFs core–shell composites show much enhanced reactivity in comparison to the Cu NCs confined in the pore of MOFs, regardless of their very similar intrinsic properties at the atomic level. Moreover, introducing polar groups on the MOF structure can further improve both the catalytic reactivity and selectivity. Mechanistic investigation reveals that the CuI sites located at the interface between Cu NCs and support serve as the active sites and efficiently catalyze CO2 photoreduction. This synergetic effect may pave the way for the design of low‐cost and efficient catalysts for CO2 photoreduction into high‐value chemical feedstock. [ABSTRACT FROM AUTHOR]

Encapsulating ultrasmall Cu nanoparticles inside Zr‐MOFs to form core–shell architecture is very challenging but of interest for CO2 reduction. We report for the first time the incorporation of ultrasmall Cu NCs into a series of benchmark Zr‐MOFs, without Cu NCs aggregation, via a scalable room temperature fabrication approach. The Cu NCs@MOFs core–shell composites show much enhanced reactivity in comparison to the Cu NCs confined in the pore of MOFs, regardless of their very similar intrinsic properties at the atomic level. Moreover, introducing polar groups on the MOF structure can further improve both the catalytic reactivity and selectivity. Mechanistic investigation reveals that the CuI sites located at the interface between Cu NCs and support serve as the active sites and efficiently catalyze CO2 photoreduction. This synergetic effect may pave the way for the design of low‐cost and efficient catalysts for CO2 photoreduction into high‐value chemical feedstock. [ABSTRACT FROM AUTHOR]

The metal-organic framework MOF-808 contains Zr 6 O 8 nodes with a high density of vacancy sites, which can incorporate carboxylate-containing functional groups to tune chemical reactivity. Although the postsynthetic methods to modify the chemistry of the Zr 6 O 8 nodes in MOFs are well known, tackling these alterations from a structural perspective is still a challenge. We have combined infrared spectroscopy experiments and first-principles calculations to identify the presence of node vacancies accessible for chemical modifications within the MOF-808. We demonstrate the potential of our approach to assess the decoration of MOF-808 nodes with different catechol-benzoate ligands. Furthermore, we have applied advanced synchrotron characterization tools, such as pair distribution function analyses and X-ray absorption spectroscopy, to resolve the atomic structure of single metal sites incorporated into the catechol groups postsynthetically. Finally, we demonstrate the catalytic activity of these MOF-808 materials decorated with single copper sites for 1,3-dipolar cycloadditions.