Plasma synthesis of metal oxide nanoparticles
AssigneeE. I. Du Pont de Nemours and Company
InventorLu Zhang
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Abstract
The present invention is a method of increasing particle surface area and decreasing the concentration of over-sized particles in a process for making metal oxide particles, particularly nanoparticle TiO2, in an inlet-fed, plug flow, plasma reactor by vapor phase reaction of titanium tetrachloride and oxygen in the presence of a source of hydrogen to form titanium dioxide particles.
Claims8
A method for synthesizing nano-sized titanium dioxide-containing particles in a plasma process comprising vapor phase reacting titanium halide and oxygen, the oxygen being in an amount in excess of the stoichiometric amount of oxygen required to react with the titanium, in the presence of an amount of a source of hydrogen, to form metal titanium dioxide nanoparticles wherein the average particle size is below 100 nm in diameter and a minor proportion of the particle aggregates are above 100 nm in diameter, the amount of the source of hydrogen being sufficient to provide the minor proportion of particle aggregates.
A method of making nanosize titanium dioxide-containing particles in a plasma reactor, comprising:
- (a) injecting into the reactor a feed gas containing oxygen and a titanium halide vapor, the oxygen of the feed gas being in an amount in excess of the stoichiometric amount of oxygen required to react with the titanium;
- (b) injecting source of hydrogen into the reactor;
- (c) generating a plasma;
- and
- (d) contacting the feed gas with the plasma in the presence of the hydrogen in an amount sufficient to form a product mixture containing titanium dioxide nanoparticles wherein the average particle size is below 100 nm in diameter and a minor proportion of the particle aggregates are above 100 nm in diameter.
Dependencies are inferred from the claim text.