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A method of pore fabrication in the walls of carbon nanotubes has been developed, leading to porous nanotubes that have been filled with catalysts and utilized in liquid- and gas-phase reactions. Chromium oxide nanoparticles have been utilized as highly effective etchants of carbon nanotube sidewalls. Tuning the thermal profile and loading of this nanoscale oxidant, both of which influence the localized oxidation of the carbon, have allowed the controlled formation of defects and holes with openings of 40–60 nm, penetrating through several layers of the graphitic carbon nanotube sidewall, resulting in templated nanopore propagation. The porous carbon nanotubes have been demonstrated as catalytic nanoreactors, effectively stabilizing catalytic nanoparticles against agglomeration and modulating the reaction environment around active centers. CO2 sorption on ruthenium nanoparticles (RuNPs) inside nanoreactors led to distinctive surface-bound intermediates (such as carbonate species), compared to RuNPs on amorphous carbon. Introducing pores in nanoreactors modulates the strength of absorption of these intermediates, as they bond more strongly on RuNPs in porous nanoreactors as compared to the nanoreactors without pores. In the liquid-phase hydrosilylation of phenylacetylene, the confinement of Rh4(CO)12 catalyst centers within the porous nanoreactors changes the distribution of the products relative to those observed in the absence of the additional pores. These changes have been attributed to the enhanced local concentration of phenylacetylene and the environment in which the catalytic centers reside within the porous carbon host.

Two-dimensional fused aromatic networks (2D FANs) have emerged as a highly versatile alternative to holey graphene. The synthesis of 2D FANs with increasingly larger lattice dimensions will enable new application perspectives. However, the synthesis of larger analogues is mostly limited by lack of appropriate monomers and methods. Herein, we describe the synthesis, characterisation and properties of an expanded 2D FAN with 90-ring hexagons, which exceed the largest 2D FAN lattices reported to date.

Three-dimensional covalent organic frameworks (3D COFs) with a pcu topology have been obtained from distorted polycyclic aromatic hydrocarbons acting as triangular antiprismatic (D3d) nodes. Such 3D COFs are six-fold interpenetrated as the result of interframework ?-stacking, which enable charge transport properties that are not expected for 3D COFs.

Understanding charge transport in 2D covalent organic frameworks is crucial to increase their performance. Herein a new wavy 2D covalent organic framework has been designed, synthesized and studied to shine light on the structural factors that dominate charge transport.

Three-dimensional covalent organic frameworks (3D COFs) with a pcu topology have been obtained from distorted polycyclic aromatic hydrocarbons acting as triangular antiprismatic (D3d) nodes. Such 3D COFs are six-fold interpenetrated as the result of interframework π-stacking, which enable charge transport properties that are not expected for 3D COFs.

Molecular motion and bond dissociation are two of the most fundamental phenomena underpinning the properties of molecular materials. We entrapped HF and H2O molecules within the fullerene C60 cage, encapsulated within a single-walled carbon nanotube (X@C60)@SWNT, where X = HF or H2O. (X@C60)@SWNT represents a class of molecular nanomaterial composed of a guest within a molecular host within a nanoscale host, enabling investigations of the interactions of isolated single di- or triatomic molecules with the electron beam. The use of the electron beam simultaneously as a stimulus of chemical reactions in molecules and as a sub-angstrom resolution imaging probe allows investigations of the molecular dynamics and reactivity in real time and at the atomic scale, which are probed directly by chromatic and spherical aberration-corrected high-resolution transmission electron microscopy imaging, or indirectly by vibrational electron energy loss spectroscopy in situ during scanning transmission electron microscopy experiments. Experimental measurements indicate that the electron beam triggers homolytic dissociation of the H–F or H–O bonds, respectively, causing the expulsion of the hydrogen atoms from the fullerene cage, leaving fluorine or oxygen behind. Because of a difference in the mechanisms of penetration through the carbon lattice available for F or O atoms, atomic fluorine inside the fullerene cage appears to be more stable than the atomic oxygen under the same conditions. The use of (X@C60)@SWNT, where each molecule X is “packaged” separately from each other, in combination with the electron microscopy methods and density functional theory modeling in this work, enable bond dynamics and reactivity of individual atoms to be probed directly at the single-molecule level.

A high degree of crystallinity is an essentialaspect in two-dimensional covalent organic frameworks, asmany properties depend strongly on the structural arrangement of the different layers and their constituents. Weintroduce herein a new design strategy based on core-twistedpolycyclic aromatic hydrocarbon as rigid nodes that give riseto a two-dimensional covalent organic framework with awavy honeycomb (chairlike) lattice. The concave−convex self- complementarity of the wavy two-dimensional lattice guides thestacking of framework layers into a highly stable and ordered covalent organic framework that allows a full 3D analysis by transmission electron microscopy revealing its chairlike honeycomb facets and aligned mesoporous channels. Remarkably, the waviness of the framework does not disrupt the interlayerπ−πstacking that shows charge transporting properties similar to those of planar covalent organic frameworks. The implementation of core-twisted aromatics as building blocks for covalent organic frameworks brings new possibilities in the design of highly ordered organic materials.

We present the synthesis of metal nanowires in a multiplexed device configuration using single-walled carbon nanotubes (SWNTs) as nanoscale vector templates. The SWNT templates control the dimensionality of the wires, allowing precise control of their size, shape and orientation; moreover a solution processable approach enables their linear deposition between specific electrode pairs in electronic devices. Electrical characterizations demonstrate the successful fabrication of metal nanowire electronic devices, while multiscale characterization of the different fabrication steps reveals details of the structure and charge transfer between the material encapsulated and the carbon nanotube. Overall the strategy presented allows facile, low-cost and direct synthesis of multiplexed metal nanowire devices for nanoelectronic applications.

The integrated analytical approach developed in this study offers a powerful methodology for the structural characterization of complex molecular nanomaterials. Structures of a covalent organic framework based on boronate esters (COF-5) and a conjugated microporous polymer (Aza-CMP) have been investigated by a combination of several electron microscopy techniques elucidating the three-dimensional topology of the complex polycrystalline (COF) and non-crystalline (CMP) materials. Unexpected, aperiodic mesoporous channels of 20-50 nm in diameter were found to be penetrating the COF and CMP particles, which cannot be detected by X-ray diffraction techniques. The mesopores appear to be stable under a range of different conditions and accessible to gas molecules, exhibiting a particular bonding capability with CO2 in the case of the CMP. The mesoporosity appears to be unrelated to the intrinsic chemical structures of the COF or CMP but rather it reflects the dynamics of polymer particle formation in a polycondensation reaction. The mesopores may be templated by clusters of solvent molecules during the COF or CMP synthesis, leaving cavities within the polymer particles. The unexpected mesoporosity discovered in COF and CMP materials begs for re-assessment of the nature of framework materials and may open new opportunities for applications of these molecular materials in gas sorption or catalysis.

We present the synthesis of metal nanowires in a multiplexed device configuration using single‐walled carbon nanotubes (SWNTs) as nanoscale vector templates. The SWNT templates control the dimensionality of the wires, allowing precise control of their size, shape and orientation; moreover a solution processable approach enables their linear deposition between specific electrode pairs in electronic devices. Electrical characterizations demonstrate the successful fabrication of metal nanowire electronic devices, while multiscale characterization of the different fabrication steps reveals details of the structure and charge transfer between the material encapsulated and the carbon nanotube. Overall the strategy presented allows facile, low‐cost and direct synthesis of multiplexed metal nanowire devices for nanoelectronic applications.

Catalysis of chemical reactions by nanosized clusters of transition metals holds the key to the provision of sustainable energy and materials. However, the atomistic behaviour of nanocatalysts still remains largely unknown due to uncertainties associated with the highly labile metal nanoclusters changing their structure during the reaction. In this study, we reveal and explore reactions of nm-sized clusters of 14 technologically important metals in carbon nano test tubes using time-series imaging by atomically-resolved transmission electron microscopy (TEM), employing the electron beam simultaneously as an imaging tool and stimulus of the reactions. Defect formation in nanotubes and growth of new structures promoted by metal nanoclusters enable the ranking of the different metals both in order of their bonding with carbon and their catalytic activity, showing significant variation across the Periodic Table of Elements. Metal nanoclusters exhibit complex dynamics shedding light on atomistic workings of nanocatalysts, with key features mirroring heterogeneous catalysis.

The use of boron nitride nanotubes as effective nanoscale containers for the confinement and thermal transformations of molecules of C60-fullerene has been demonstrated. The gas-phase insertion of fullerenes into the internal channel of boron nitride nanotubes yields quasi-one-dimensional arrays, with packing arrangements of the guest-fullerenes different to those in the bulk crystal and critically dependent on the internal diameter of the host-nanotube. Interestingly, the confined fullerene molecules (i) exhibit dynamic behaviour and temperature-dependant phase transitions analogous to that observed in the bulk crystal and (ii) can be effectively removed from within the internal channel of nanotubes by excessive sonication in organic solvent, indicating weak host-guest interactions. The thermal treatment of fullerenes confined within nanotubes at 1200 °C in argon triggers the polymerisation and coalescence of the guest-fullerenes into carbon nanotubes inside boron nitride nanotubes affording a hybrid nanostructure – the world’s smallest coaxial cable – on a preparative scale, as confirmed by high resolution bright field transmission electron microscopy (TEM) imaging and electron energy loss spectroscopy, energy filtered transmission electron microscopy (EELS, EFTEM) elemental mapping and UV-vis absorption spectroscopy.