Mixed-valent oxide-catalytic carbonization for synthesis of monodispersed nano sized carbon spheres

Abstract

Abstract A mixed-valent oxide-catalytic carbonization process for synthesizing monodispersed carbon spheres at very low cost is reported for the first time. The carbon spheres are formed by catalytic carbonization of natural gas (primarily methane) with the assistance of mixed-valent metal oxides. The catalyst is reusable and the entire synthesis process produces no environmental waste. The product can be controlled by temperature to produce macroscopic quantities and a high percentage (>95%) of nano sized carbon spheres; thus, measurements of their physical properties can be performed easily. The carbon spheres are solid and comprise layered graphitic flakes. The sphere is nucleated from a pentagonal carbon ring, followed by a spiral shell growth. When the sphere grows larger, graphitic flakes of atomic thickness are nucleated on the surface owing to the nucleation of the paired pentagonal-heptagonal (P-H) carbon rings. The combination of the P-H carbon rings with the hexagonal networks produces eight ba...