Method for producing encapsulated nanoparticles and carbon nanotubes using catalytic disproportionation of carbon monoxide

A method for the production of carbon encapsulated nanoparticles, carbon nanotubes and other closed carbon structures, including contacting a catalyst of a transition metal, or a compound or alloy thereof, with a gas mixture containing carbon monoxide, and an amount of available molecular hydrogen which is insufficient to cause formation of graphite plane edges through capping, at a temperature in the range from 300 DEG -1000 DEG C., to provide closed carbon structures, which are useful in the preparation of thermal composites, reinforcement composites and magnetic particle recording media.