Methods of oxidizing multiwalled carbon nanotubes
AssigneeHyperion Catalysis International, Inc.
InventorsChunming Niu, David Moy, Asif Chishti, Robert Hoch
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Abstract
Methods of oxidizing multiwalled carbon nanotubes are provided. The multiwalled carbon nanotubes are oxidized by contacting the carbon nanotubes with gas-phase oxidizing agents such as CO2, O2, steam, N2O, NO, NO2, O3, and ClO2. Near critical and supercritical water can also be used as oxidizing agents. The multiwalled carbon nanotubes oxidized according to methods of the invention can be used to prepare rigid porous structures which can be utilized to form electrodes for fabrication of improved electrochemical capacitors.
Claims51
A method of oxidizing multiwalled carbon nanotubes having a diameter no greater than 1 micron, said method comprising
- growing multiwalled carbon nanotubes on a supported catalyst, said supported catalyst comprising a catalyst and a catalyst support,
- contacting said multiwalled carbon nanotubes with a gas-phase oxidizing agent selected from the group consisting of CO2, O2, steam, N2O, NO, NO2, O3, ClO2 and mixtures thereof under conditions sufficient to form oxidized nanotubes which exhibit upon titration an acid titer of from 0.05 to about 0.6 meq/g,
- wherein said oxidized nanotubes include said supported catalyst.
A method for producing a network of carbon nanotubes comprising the steps of:
- (a) growing multiwalled carbon nanotubes on a supported catalyst, said supported catalyst comprising a catalyst and a catalyst support,
- (b) oxidizing said carbon nanotubes with a gas-phase oxidizing agent selected from a group consisting of CO2, O2, steam, N2O, NO, NO2, O3, ClO2 and mixtures thereof under conditions sufficient to form oxidized nanotubes, wherein said oxidized nanotubes include said supported catalyst.
- (c) subjecting said oxidized nanotubes to conditions sufficient to cause crosslinking.
A method for producing a network of functionalized carbon nanotubes comprising the steps of:
- (a) growing carbon nanotubes on a supported catalyst, said supported catalyst comprising a catalyst and a catalyst support,
- (b) oxidizing said carbon nanotubes with a gas-phase oxidizing agent selected from a group consisting of CO2, O2, steam, N2O, NO, NO2, O3, ClO2 and mixtures thereof under conditions sufficient to form oxidized nanotubes, wherein said oxidized nanotubes include said supported catalyst;
- (c) treating said oxidized nanotubes with a reactant suitable to react with moieties of said oxidized nanotubes thereby adding at least a secondary group onto the surface of said oxidized nanotubes;
- (d) further contacting said nanotubes bearing secondary groups with an effective amount of crosslinking agent.
A method of treating aggregates of carbon nanotubes which comprises
- growing aggregates of carbon nanotubes on a supported catalyst, said supported catalyst comprising a catalyst and a catalyst support,
- contacting said aggregates with an gas-phase oxidizing agent selected from a group consisting of CO2, O2, steam, N2O, NO, NO2, O3, ClO2 and mixtures thereof under conditions sufficient to oxidize said carbon nanotube aggregates which exhibit upon titration an acid titer of from 0.05 to about 0.6 meq/g,
- wherein said oxidized carbon nanotube aggregates include said supported catalyst.
Dependencies are inferred from the claim text.