# US 7,744,673 B2 · Hollow sphere metal oxides > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,744,673 B2 - Document ID: US7744673B2 - Status: Granted - Kind: B2 - Application number: 11/876,338 - Filed: 2007-10-22 - Published: 2008-09-04 - Granted: 2010-06-29 - Earliest claimed: 2006-10-27 - Assignees: Stc.Unm - Inventors: Xingmao Jiang; Charles Jeffrey Brinker - Web page: https://patentgrep.com/patent/US7744673B2 ## CPC - B01J 13/0095: {Preparation of aerosols} - B01J 13/02: Making microcapsules or microballoons {(for medical preparations A61K9/50)} - B22F 1/0549: {Hollow particles, including tubes and shells} - B22F 3/1112: {comprising hollow spheres or hollow fibres} - B22F 2998/00: Supplementary information concerning processes or compositions relating to powder metallurgy - B22F 2999/00: Aspects linked to processes or compositions used in powder metallurgy - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER ## Abstract In accordance with invention, there are methods for fabricating hollow spheres and nanofoams. The method for making hollow spheres can include providing a homogeneous precursor solution including a first solvent and one or more anhydrous precursor species and forming aerosol droplets having a first size distribution using the homogeneous precursor solution in an anhydrous carrier gas. The method can also include transporting the aerosol droplets through an aerosol reactor including a reactant to form a plurality of hollow spheres, wherein each of the plurality of hollow spheres can be formed by one or more chemical reactions occurring at a surface of the aerosol droplet. The method can further include controlling size and thickness of the hollow spheres by one or more of the precursor solution concentration, aerosol droplet size, temperature, residence time of the aerosol droplets in the aerosol reactor, and the reactant distribution in the aerosol reactor. ## Claims ### Claim 1 A method for fabricating hollow spheres comprising: providing a homogeneous precursor solution comprising a first hydrophobic solvent and one or more anhydrous precursor species; forming aerosol droplets having a first size distribution using the homogeneous precursor solution in an anhydrous carrier gas; transporting the aerosol droplets through an aerosol reactor containing a reactant to form a plurality of hollow spheres, wherein each of the plurality of hollow spheres is formed by one or more chemical reactions occurring at a surface of the aerosol droplet; and controlling size and thickness of the hollow spheres by one or more of the precursor solution concentration, aerosol droplet size, temperature, residence time of the aerosol droplets in the aerosol reactor, and the reactant distribution in the aerosol reactor. ### Claim 2 (depends on 1) The method of claim 1, wherein the first hydrophobic solvent comprises one or more anhydrous volatile inert hydrophobic solvents and the reactant comprises water. ### Claim 3 (depends on 2) The method of claim 2, wherein the precursor species comprises one or more of metal alkoxides and metal chlorides. ### Claim 4 (depends on 3) The method of claim 3, wherein the precursor species comprises one or more of tin, germanium, titanium, silicon, zinc, zirconium, cadmium, lead, and mercury. ### Claim 5 (depends on 3) The method of claim 3, wherein the hollow sphere comprises a metal oxide shell. ### Claim 6 (depends on 5) The method of claim 5 further comprising converting the metal oxide shell to a metal shell. ### Claim 7 (depends on 1) The method of claim 1 further comprising annealing the plurality of hollow spheres to convert the hollow spheres from an amorphous state to a multi-crystalline state. ### Claim 8 (depends on 1) The method of claim 1, wherein the first hydrophobic solvent comprises one or more anhydrous volatile inert hydrophobic solvents and the reactant comprises one or more of hydrogen sulfide, volatile sulfides, hydrogen, and aldehydes. ### Claim 9 (depends on 8) The method of claim 8, wherein the hollow sphere comprises one or more of a metal shell and a metal sulfide shell. ### Claim 10 (depends on 9) The method of claim 9, wherein the metal is selected from the group consisting of silver, copper, gold, platinum, palladium, zinc, zirconium, cadmium, lead, and mercury. ### Claim 11 (depends on 1) The method of claim 1, wherein the aerosol reactor further contains a catalyst. ### Claim 12 (depends on 11) The method of claim 11, wherein the catalyst comprises one or more of ammonia, organic amines, hydrogen chloride, and organic acids. ### Claim 13 (depends on 1) The method of claim 1, wherein the homogeneous precursor solution further comprises one or more pharmaceutical compositions. ### Claim 14 (depends on 13) The method of claim 13, wherein the one or more hollow spheres comprise one or more pharmaceutical compositions. ### Claim 15 (depends on 1) The method of claim 1, wherein the precursor species comprises one or more of quantum dots, magnetic nanoparticles, and preformed nanocrystallines. ### Claim 16 (depends on 15) The method of claim 15, wherein the one or more hollow spheres comprise one or more of quantum dots, magnetic nanoparticles, and preformed nanocrystallines. ### Claim 17 A method for fabricating nanofoam comprising: providing a homogeneous precursor solution comprising a first hydrophobic solvent and one or more anhydrous precursor species; forming aerosol droplets having a first size distribution using the homogeneous precursor solution in an anhydrous carrier gas; transporting the aerosol droplets through an aerosol reactor containing a reactant, wherein one or more chemical reactions occurs at a surface of the aerosol droplet to form partially consolidated hollow sphere; and aggregating partially consolidated hollow spheres to form nanofoam. ### Claim 18 (depends on 17) The method of claim 17, wherein the first hydrophobic solvent comprises one or more anhydrous volatile inert hydrophobic solvents and the reactant comprises water. ### Claim 19 (depends on 18) The method of claim 18, wherein the precursor species comprises one or more of metal alkoxides and metal chlorides. ### Claim 20 (depends on 19) The method of claim 19, wherein the precursor species comprises one or more of tin, germanium, titanium, silicon, zinc, zirconium, cadmium, lead, and mercury. ### Claim 21 (depends on 19) The method of claim 19, wherein the nanofoam comprises one or more of a metal oxide shell and a metal shell. ### Claim 22 (depends on 17) The method of claim 17, wherein the first hydrophobic solvent comprises one or more anhydrous volatile inert hydrophobic solvents and the reactant comprises one or more of hydrogen sulfide, volatile sulfides, hydrogen, and aldehydes. ### Claim 23 (depends on 19) The method of claim 19, wherein the nanofoam comprises one or more of a metal shell and a metal sulfide shell. ### Claim 24 (depends on 22) The method of claim 22, wherein the metal is selected from the group consisting of silver, copper, gold, platinum, palladium, zinc, zirconium, cadmium, lead, and mercury. ### Claim 25 (depends on 17) The method of claim 17, wherein the nanofoam comprise one or more of pharmaceutical composition, quantum dots, magnetic nanoparticles, and preformed nanocrystallines.