Carbon nanostructures manufactured from catalytic templating nanoparticles

Abstract

Methods for manufacturing carbon nanostructures include: 1) forming a plurality of catalytic templating particles using a plurality of dispersing agent molecules; 2) forming an intermediate carbon nanostructure by polymerizing a carbon precursor in the presence of the plurality of templating nanoparticles; 3) carbonizing the intermediate carbon nanostructure to form a composite nanostructure; and 4) removing the templating nanoparticles from the composite nanostructure to yield the carbon nanostructures. The carbon nanostructures are well-suited for use as a catalyst support. The carbon nanostructures exhibit high surface area, high porosity, and high graphitization. Carbon nanostructures according to the invention can be used as a substitute for more expensive and likely more fragile carbon nanotubes.

1 . A composition of matter comprising a plurality of carbon nanostructures having a graphitic structure and a BET specific surface area greater than about 120 m 2 /g, the carbon nanostructures being manufactured according to a process comprising:
 (i) forming a plurality of catalytic templating nanoparticles by:
 (a) reacting a plurality of precursor catalyst atoms with a plurality of organic dispersing agent molecules to form complexed catalyst atoms; and 
 (b) allowing or causing the complexed catalyst atoms to form the templating nanoparticles; 
   (ii) forming intermediate carbon nanostructures by polymerizing a carbon precursor in the presence of the templating nanoparticles;   (iii) carbonizing the intermediate carbon nanostructures to form a plurality of composite nanostructures; and   (iv) removing the templating nanoparticles from the composite nanostructures to yield the carbon nanostructures.   
     
     
         2 . A composition of matter as defined in  claim 1 , wherein the precursor catalyst atoms used to form the catalytic templating nanoparticles comprise at least one of iron, nickel, or cobalt. 
     
     
         3 . A composition of matter as defined in  claim 1 , wherein the dispersing agent molecules used to form the catalytic templating nanoparticles are capable of bonding with the precursor catalyst atoms and comprise at least one functional group selected from the group consisting of a hydroxyl, a carboxyl, a carbonyl, an amine, an amide, a nitrile, a nitrogen with a free lone pair of electrons, an amino acid, a thiol, a sulfonic acid, a sulfonyl halide, an acyl halide, and combinations thereof. 
     
     
         4 . A composition of matter as defined in  claim 1 , wherein the dispersing agent molecules used to form the catalytic templating nanoparticles comprise at least one member selected from the group consisting of oxalic acid, malic acid, malonic acid, maleic acid, succinic acid, glycolic acid, lactic acid, glucose, citric acid, pectins, cellulose, ethanolamine, mercaptoethanol, 2-mercaptoacetate, glycine, sulfobenzyl alcohol, sulfobenzoic acid, sulfobenzyl thiol, sulfobenzyl amine, polyacrylates, polyvinylbenzoates, polyvinyl sulfate, polyvinyl sulfonates, polybisphenol carbonates, polybenzimidizoles, polypyridine, sulfonated polyethylene terephthalate, and combinations thereof. 
     
     
         5 . A composition of matter as defined in  claim 1 , wherein the carbon precursor used to form the intermediate carbon nanostructures comprises a hydrothermally polymerizable organic substrate that comprises at least one of citric acid, acrylic acid, benzoic acid, acrylic ester, butadiene, styrene, or cinnamic acid. 
     
     
         6 . A composition of matter as defined in  claim 1 , wherein the carbon precursor used to form the intermediate carbon nanostructures comprises at least one of resorcinol-formaldehyde-gel, phenol resin, melamine-formaldehyde gel, poly(furfuryl alcohol), or poly(acrylonitrile). 
     
     
         7 . A composition of matter as defined in  claim 1 , wherein the templating nanoparticles are formed prior to being mixed with the carbon precursor. 
     
     
         8 . A composition of matter as defined in  claim 1 , wherein at least a portion of the templating nanoparticles are removed from the composite nanostructures by etching with at least one of an acid or a base to yield the carbon nanostructures. 
     
     
         9 . A composition of matter as defined in  claim 1 , the carbon nanostructures being composed of hollow multi-walled structures, each multi-walled structure being formed from multiple graphitic layers. 
     
     
         10 . A composition of matter as defined in  claim 1 , wherein (a) further comprises mixing and reacting a ground state metal comprising the precursor catalyst atoms with the organic dispersing agent molecules to form the complexed catalyst atoms and adding a base to adjust the pH to above 8 and below about 13. 
     
     
         11 . A composition of matter as defined in  claim 1 , further comprising catalyst particles on the carbon nanostructures. 
     
     
         12 . A composition of matter comprising a plurality of carbon nanostructures having a graphitic structure and a BET specific surface area greater than about 120 m 2 /g and being composed of hollow multi-walled sphere-like carbon nanostructures, each multi-walled sphere-like carbon nanostructure being formed from multiple graphitic layers and having a single interior hole defining an interior diameter of the sphere-like carbon nanostructure, the carbon nanostructures being manufactured according to a process comprising:
 (i) providing a plurality of solid catalytic templating nanoparticles consisting essentially of one or more types of metal catalyst atoms and optionally one or more types of organic dispersing agent molecules;   (ii) mixing the solid catalytic templating nanoparticles with a carbon precursor and polymerizing the carbon precursor in the presence of the solid catalytic templating nanoparticles to form a plurality of intermediate carbon nanostructures;   (iii) carbonizing the intermediate carbon nanostructures to form a plurality of composite nanostructures; and   (iv) removing the templating nanoparticles from the composite nanostructures to yield the carbon nanostructures.   
     
     
         13 . A composition of matter as defined in  claim 12 , wherein the metal catalyst atoms comprise at least one of iron, nickel, or cobalt and the dispersing agent molecules comprise at least one functional group selected from the group consisting of a hydroxyl, a carboxyl, a carbonyl, an amine, an amide, a nitrile, a nitrogen with a free lone pair of electrons, an amino acid, a thiol, a sulfonic acid, a sulfonyl halide, an acyl halide, and combinations thereof. 
     
     
         14 . A composition of matter as defined in  claim 12 , wherein the dispersing agent molecules comprise at least one member selected from the group consisting of oxalic acid, malic acid, malonic acid, maleic acid, succinic acid, glycolic acid, lactic acid, glucose, citric acid, pectins, cellulose, ethanolamine, mercaptoethanol, 2-mercaptoacetate, glycine, sulfobenzyl alcohol, sulfobenzoic acid, sulfobenzyl thiol, sulfobenzyl amine, polyacrylates, polyvinylbenzoates, polyvinyl sulfate, polyvinyl sulfonates, polybisphenol carbonates, polybenzimidizoles, polypyridine, sulfonated polyethylene terephthalate, and combinations thereof. 
     
     
         15 . A composition of matter as defined in  claim 12 , wherein the carbon precursor comprises a hydrothermally polymerizable organic substrate that comprises at least one of citric acid, acrylic acid, benzoic acid, acrylic ester, butadiene, styrene or cinnamic acid. 
     
     
         16 . A composition of matter as defined in  claim 12 , wherein the carbon precursor comprises at least one of resorcinol-formaldehyde-gel, phenol resin, melamine-formaldehyde gel, poly(furfuryl alcohol), or poly(acrylonitrile). 
     
     
         17 . A composition of matter as defined in  claim 12 , wherein the solid catalytic templating nanoparticles are provided in an aqueous medium having pH greater than 8 and less than about 13. 
     
     
         18 . A composition of matter comprising:
 a plurality of carbon nanostructures,
 the carbon nanostructures having a graphitic structure and a BET specific surface area greater than about 120 m 2 /g, 
 the carbon nanostructures being composed of hollow multi-walled sphere-like carbon nanostructures, each multi-walled sphere-like carbon nanostructure being formed from multiple graphitic layers and having a single interior hole defining an interior diameter of the sphere-like carbon nanostructure. 
   
     
     
         19 . A composition of matter as defined in  claim 18 , at least some of the sphere-like carbon nanostructures further including a catalytic templating nanoparticle disposed within the single interior hole. 
     
     
         20 . A composition of matter as defined in  claim 18 , further comprising catalyst particles on the carbon nanostructures.