The development of next‐generation molecular‐electronic, electrocatalytic, and energy‐storage systems depends on the availability of robust materials in which molecular charge‐storage sites and conductive hosts are in intimate contact. It is shown here that electron transfer from single‐walled carbon nanotubes (SWNTs) to polyoxometalate (POM) clusters results in the spontaneous formation of host–guest POM@SWNT redox‐active hybrid materials. The SWNTs can conduct charge to and from the encapsulated guest molecules, allowing electrical access to >90% of the encapsulated redox species. Furthermore, the SWNT hosts provide a physical barrier, protecting the POMs from chemical degradation during charging/discharging and facilitating efficient electron transfer throughout the composite, even in electrolytes that usually destroy POMs.

This is a repository copy of Atomic Mechanism of Metal Crystal Nucleus Formation in a Single-Walled Carbon Nanotube.

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.

Electron transfer processes play a significant role in host-guest interactions and determine physicochemical phenomena emerging at the nanoscale that can be harnessed in electronic or optical devices as well as biochemical and catalytic systems. We have developed a novel method for qualifying and quantifying the electronic doping of single walled carbon nanotubes (SWNT) using electrochemistry and have established a direct link between these experimental measurements and ab initio DFT calculations. Metallocenes such as cobaltocene and methylated ferrocene derivatives were encapsulated inside SWNT (1.4 nm diameter) and the cyclic voltammetry (CV) performed. The electron transfer between guest-molecules and host-SWNT is measured as a function of shift in the redox potential (E1/2) . Furthermore, the shift in E1/2 is shown to be inversely proportional to the nanotube diameter. For the quantification of the amount of electron transfer from the guestmolecules on the SWNT, a novel method using coulometry was developed allowing the mapping of the density of states (DOS) and the Fermi level of the SWNT. Correlated with theoretical calculations, coulometry provides an accurate indication of n/p-doping of the SWNT.

In spite of the high potential of endohedral metallofullerenes (EMFs) for application in biology, medicine and molecular electronics and recent efforts in EMF synthesis, the variety of EMFs accessible by conventional synthetic methods remains limited and does not include, for example, EMFs of late transition metals. We propose a method in which EMF formation is initiated by electron irradiation in aberration-corrected high-resolution transmission electron spectroscopy (AC-HRTEM) of a metal cluster surrounded by amorphous carbon inside a carbon nanotube serving as a nano-reactor and apply this method for synthesis of nickel EMFs. The use of AC-HRTEM makes it possible not only to synthesize new, previously unattainable nanoobjects but also to study in situ the mechanism of structural transformations. Molecular dynamics simulations using the state-of-the-art approach for modeling the effect of electron irradiation are performed to rationalise the experimental observations and to link the observed processes with conditions of bulk EMF synthesis.KEYWORDS endohedral metallofullerenes, electron irradiation, transmission electron microscopy, molecular dynamics, carbon nanotube Endohedral metallofullerens (EMFs) and their derivatives have shown considerable promise for biological and medical applications and for molecular electronics 1,2,3 . However, the variety of EMFs available by current synthetic methods is very limited. Traditional methods for the synthesis of EMFs in the arc discharge reactor or via laser evaporation are restricted principly to alkali earth elements, lanthanides and early transition metals (groups 2 -4 of the Periodic Table), see Refs. 1