Small angle neutron and X-ray studies of carbon structures with metal atoms

Abstract

Encapsulation of metal atoms inside carbon single-wall cages or within multi-layer cells has been realized using molecular precursors and high temperature processes transforming them into desirable structures. Endohedral fullerenols Fe@C₆₀(OH)_X with 3d-metal (iron) have been studied by SANS in aqueous solutions where they form stable globular clusters with radii R _C ∼ 10-12 nm and aggregation numbers N _C ∼ 10⁴. This self-assembly is a crucial feature of paramagnetic fullerenols as perspective contrast agents for Magneto-Resonance Imaging in medicine. Cellular carbon-metal structures have been created by the pyrolysis of diphthalocyanines of lanthanides and actinides. It was established that these ultra porous matrices consist of globular cells of molecular precursor size (∼ 1 nm) which are aggregated into superstructures. This provides retain of metal atoms inside matrices which may serve for safety storage of spent fuel of nuclear power plants.