Method of determining lifetime of a nanotube-producing catalyst
AssigneeHonda Motor Co., Ltd.
InventorsElena Mora, Avetik Harutyunyan
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Abstract
The present teachings are directed toward methods of determining the lifetime of a catalyst for producing carbon nanotubes. The methods include providing different isotopically-labeled reaction components, primarily hydrocarbon sources containing different carbon isotopes, to the catalyst and measuring the Raman spectra of the carbon nanotubes produced with the different hydrocarbon sources.
Claims23
A method of measuring the lifetime of a catalyst for producing carbon nanotubes comprising:
- providing first and second independent samples of a catalyst suitable to produce carbon nanotubes;
- exposing independently each of the first and second independent catalyst samples to a first hydrocarbon source containing predominantly a first isotope of carbon therein for a first and a second time period, respectively;
- allowing the first hydrocarbon source to react to produce a first portion of carbon nanotubes containing the first isotope of carbon at each of the first and second independent catalyst samples;
- exposing independently each of the first and second independent catalyst samples to a second hydrocarbon source containing predominantly a second isotope of carbon therein for a third and fourth time period, respectively;
- allowing the second hydrocarbon source to react to produce a second portion of carbon nanotubes containing the second isotope of carbon at each of the first and second independent catalyst samples;
- and
- measuring the physical properties of the carbon nanotubes grown at the first and second independent catalyst samples to determine the lifetime of the catalyst,
- wherein the lengths of the first, second, third and fourth time periods are independently varied, and the first and the second catalyst are each exposed to a hydrocarbon source until carbon nanotubes are no longer produced.
A method for reducing the amount of disordered carbon product present in carbon nanotubes comprising
- providing a catalyst for producing carbon nanotubes;
- determining the lifetime of the catalyst for producing carbon nanotubes;
- providing a hydrocarbon source;
- exposing the hydrocarbon source to the catalyst for a time period determined by the lifetime of the catalyst;
- producing carbon nanotubes at the catalyst from the hydrocarbon source;
- and
- isolating the carbon nanotubes.
A method of measuring the lifetime of a catalyst for producing carbon nanotubes comprising:
- providing first and second independent samples of a catalyst suitable to produce carbon nanotubes;
- exposing independently each of the first and second independent catalyst samples to a first hydrocarbon source containing predominantly a first isotopically labeled component therein for a first and a second time period, respectively;
- allowing the first hydrocarbon source to react to produce a first portion of carbon nanotubes containing the first isotopically labeled component at each of the first and second independent catalyst samples;
- exposing independently each of the first and second independent catalyst samples to a second hydrocarbon source containing predominantly a second isotopically labeled component therein for a third and fourth time period, respectively;
- allowing the second hydrocarbon source to react to produce a second portion of carbon nanotubes containing the second isotopically labeled component at each of the first and second independent catalyst samples;
- and
- measuring the physical properties of the carbon nanotubes grown at the first and second independent catalyst samples to determine the lifetime of the catalyst.
Dependencies are inferred from the claim text.