Laser pyrolysis method for producing carbon nano-spheres
OwnerJ. McKinnon, Andrew Herring +1inventors
InventorsJ. McKinnon, Andrew Herring, Bryan McCloskey
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Abstract
The present invention encompasses methods and apparatus for creating metal nanoparticles embedded in a carbonanceous char, the conversion of an carbonaceous char with embedded metallic nanoparticles to graphite-encased nano-sized metal particles surrounded by char, the separation of the graphite encased metal particles from the char matrix, and the related preparation and isolation of carbon nanosphere materials with or without the enclosed metal nanoparticles, and the uses of such carbon nanospheres and graphite enclosed metal nanoparticles as supports and enhancers for fuel cell electrocatalysts and other applications.
Claims35
A method for synthesizing hollow carbon nanospheres and nanometer-scale metallic particles from a carbon-based substrate doped with a metal salt, and for recovering either one or both of these products, comprising the sequential steps of:
- (a) doping a carbon-based substrate with about 1-99 wt. % of a metal salt;
- (b) heating the doped substrate in an inert gas atmosphere to a first heating temperature of about 200° C. to about 400° C. for a period sufficient to produce initial charring of the substrate to form amorphous carbon and metal nanoparticles;
- (c) cooling the charred substrate and separating metal nanoparticles from a first portion of the charred substrate if desired;
- and,
- (d) pyrolyzing a second portion of the charred substrate by heating it to a second heating temperature of about 2000° C. or higher in an inert gas atmosphere for a period sufficient to produce carbon nanospheres.
A carbon nanosphere material prepared by the sequential steps of:
- (a) doping a carbon-based substrate with about 1-99 wt. % of a metal salt;
- (b) heating the doped substrate in an inert gas atmosphere to a first heating temperature of about 200° C. to about 400° C. for a period sufficient to produce initial charring of the substrate to form amorphous carbon and metal nanoparticles;
- and,
- (c) pyrolyzing at least a portion of the charred substrate by heating it to a second heating temperature of about 2000° C. or higher in an inert gas atmosphere for a period sufficient to produce carbon nanospheres.
A metal nanoparticle material prepared by the sequential steps of:
- (a) doping a carbon-based substrate with about 1-99 wt. % of a metal salt;
- (b) heating the doped substrate in an inert gas atmosphere to a first heating temperature of about 200° C. to about 400° C. for a period sufficient to produce initial charring of the substrate to form amorphous carbon and metal nanoparticles;
- and,
- (c) cooling at least a portion of the charred substrate and subjecting it to a mild oxidation to separate the metal nanoparticles from the carbonaceous material.
Dependencies are inferred from the claim text.