Patent ID: 6849245

Claim:
A method for producing a carbon nanostructure from an unsupported powdered metal catalyst, which method comprises: mixing a) one or more metal compounds selected from the group consisting of metal carbonates, metal nitrates, and metal hydroxides, wherein at least one of the metals is a Group VIII metal, with b) one or more dispersing agents selected from the group consisting of alkaline halides, alkaline-earth halides, and metal oxides; calcining the resulting mixture at a temperature from about 200° C. to about 400° C. for an effective amount of time to convert at least the metal compound to its respective oxide; milling the calcined mixture for an effective amount of time to decrease the particles comprising the mixture to a predetermined size, wherein the dispersing agent, during milling, serves to keep the metal powder particles from agglomerating; treating the milled, calcined mixture of particles with hydrogen for an effective amount of time and temperature to chemically reduce at least a portion of the catalytic metal oxides to the metallic state; and decomposing a carbon-containing compound having up to about 8 carbon atoms in the presence of at least a portion of the reduced milled, calcined mixture of catalytic metal particles and discrete dispersing agent at a temperature from about 450° C. to about 800° C.