Methods and catalysts for the manufacture of carbon fibrils
An improved catalyst for producing carbon fibrils is made by incorporating an effective yield-enhancing amount of a carboxylate into a fibril-forming catalyst. Alternatively, such a catalyst is made by coprecipitating a compound of a metal having fibril-forming catalytic properties and an aluminum and/or magnesium compound, optionally in the presence of carbon particles or carbon fibril aggregates. The catalyst may also be made by incorporating a compound of a fibril-forming metal onto magnesia particles in carbon particles or carbon fibril aggregates. The catalysts, methods of using them to form carbon fibrils and those carbon fibrils are also disclosed.
1. A method for the production of carbon fibrils comprising passing a fibril-forming feedstock under temperature and pressure conditions suitable for formation of fibrils over a supported fibril-forming catalyst made by a process comprising the steps of:
precipitating an effective amount of a catalyst compound of a carbon-fibril-forming catalyst metal from an aqueous solution onto a slurry of support particles in the presence of an effective amount of a carboxylate to enhance the amount of carbon fibrils produced per weight catalyst used in a gas synthesis process compared with the amount of fibrils which would have been produced in said gas synthesis process per weight of said catalyst made without said precipitating in the presence of said carboxylate,
wherein said metal-containing carbon-fibril-forming catalyst compound comprises at least one metal derived from a metal-containing compound, said metal-containing compound being different from the carboxylate, and also being different from a compound from which the carboxylate is derived, said carboxylate comprising an anion of a water soluble carboxylic acid.