Interactions of Gold Nanoparticles with the Interior of Hollow Graphitized Carbon Nanofibers

Abstract

Interactions of free-standing gold nanoparticles and hollow graphitized nanofibers in colloidal suspension are investigated, revealing the first example of the controlled arrangement of nanoparticles inside nano-containers, as directed by their internal structure. The ordering is highly effective for small gold nanoparticles whose sizes are commensurate with the height of graphitic step-edges in the graphitized carbon nanofibers and is less effective for larger gold nanoparticles. Studies aimed at understanding the role of the organic-solvent surface tension, employed for the filling experiments, demonstrate that gold nanoparticles become preferentially anchored into the hollow graphitized carbon nanofibers under a mixture of pentane/CO(2) in supercritical conditions. It is shown that a three-step cleaning procedure enables effective removal of gold nanoparticles adsorbed on the exterior surface of graphitized carbon nanofibers, while ordered arrays of encapsulated nanoparticles are retained.

Molybdenum Dioxide in Carbon Nanoreactors as a Catalytic Nanosponge for the Efficient Desulfurization of Liquid Fuels

“…In addition, the performance of molybdenum-based nanocatalysts can be optimized using support materials, which are known to both stabilize nanoparticles against sintering and promote further activity by facilitating charge transfer between the catalysts and the support material. [24,25] Hollow graphitized nanofibers (GNFs) with an internal diameter of 60 nm-structural analogues to carbon nanotubes, but possessing nanoscale step-edges on the inside-are particularly attractive as their corrugated interior surfaces promote the formation and enhance the stability of catalytic centers, [26][27][28] while increasing the concentration of reactants around the catalyst, without restricting the transport of reactants to and products from the internal cavity (the critical dimensions of most small molecules are typically at least two orders of magnitude smaller than the internal diameter of GNFs). [20][21][22][23] Among catalyst supports, hollow carbon nanostructures, such as carbon nanotubes, may offer several potential benefits for ODS catalysts.…”

Assembly and Magnetic Bistability of Mn3O4 Nanoparticles Encapsulated in Hollow Carbon Nanofibers

“…[6] The main drawback of these approaches is a lack of control over the composition, size, and morphology of the nanoparticles formed inside the nanotubes. [9][10][11] Even though the size, shape, and composition of preformed nanoparticles can be effectively controlled by various preparation methods, [12,13] the control of nanoparticle assemblies and their associated properties, combined with their confinement within carbon nanostructures, still remains a challenge. [7] The insertion of preformed nanoparticles with well-defined magnetic properties into carbon nanostructures, under conditions where their structures and properties are fully retained, could offer a powerful route for the development of novel architectures for spintronic devices.…”

New Pathway for Heterogenization of Molecular Catalysts by Non-covalent Interactions with Carbon Nanoreactors

“…Indeed, it has been demonstrated previously for various metal nanoparticles that guest species are located predominantly on these step-edge sites. [17,18,19] Furthermore, the diameters of GNFs are sufficiently large to minimise diffusion resistance of the reactant and product molecules to and from the catalytic centres. by HR-TEM and although fullerene-free molecules were not resolved in the micrograph, the presence of the copper containing species was also confirmed by EDX.…”