Method of forming high surface area metal oxide nanostructures and applications of same

Abstract

A method of forming metal oxide nanostructures on a metallic material includes applying a hot water process to the metallic material, which includes treating the metallic material with hot water under a treatment condition for a period of time so as to form metal oxide nanostructures on a surface of the metallic material, where the treated metallic material with metal oxide nanostructures under the hot water process has a high surface area that is higher than its pristine surface area of the metallic material. Also, a method of depositing metal oxide nanostructures on a target material includes applying a hot water process to a source metallic material and the target material, which includes treating the source metallic material and the target material with hot water under a treatment condition for a period of time so as to form metal oxide nanostructures on a surface of the target material.

What is claimed is: 
     
         1 . A method of forming metal oxide nanostructures on a metallic material, comprising:
 applying a hot water process to the metallic material, comprising treating the metallic material with hot water under a treatment condition for a period of time so as to form metal oxide nanostructures on a surface of the metallic material, wherein the treated metallic material with metal oxide nanostructures under the hot water process has a high surface area that is higher than its pristine surface area of the metallic material.   
     
     
         2 . The method of  claim 1 , wherein the hot water is a liquid phase of water, a gas phase of water, or a combination thereof. 
     
     
         3 . The method of  claim 2 , wherein the step of treating the metallic material with the hot water comprises immersing the metallic material the hot water, or applying a steam of the hot water at the metallic material. 
     
     
         4 . The method of  claim 3 , wherein the hot water is stirred at various flow patterns, flown at a direction, or in the steam applied at an angle relative to the surface of the metallic material. 
     
     
         5 . The method of  claim 1 , wherein the hot water comprises a type of water with different levels of purity, resistivity, dissolved oxygen, or mineral content. 
     
     
         6 . The method of  claim 1 , wherein the metallic material comprises one or more metallic compositions including elemental metals, alloys, compounds, a combination thereof, or a combination of metallic and non-metallic materials. 
     
     
         7 . The method of  claim 1 , wherein the metallic material comprises a one-dimensional (1D), two-dimensional (2D), or three-dimensional (3D) metallic material. 
     
     
         8 . The method of  claim 7 , wherein the 1D metallic material has a fiber, wire or rod geometry, the 2D metallic material has a plate, foil or thin film geometry, or the 3D metallic material has a powder, pipe, mesh or foam geometry. 
     
     
         9 . The method of  claim 7 , wherein the metallic material is in a form of substrate being electrically charged or neutral. 
     
     
         10 . The method of  claim 1 , wherein the treatment condition comprises a temperature in a variety of ranges such that the hot water is liquid water at ambient temperatures, warm water below boiling point, boiling water, or steam at much higher temperatures. 
     
     
         11 . The method of  claim 10 , wherein the treatment condition further comprises a variety of environmental pressures including different atmospheric pressures at different altitudes and high or low pressures achieved in a special container, and a variety of dissolved oxygen levels. 
     
     
         12 . The method of  claim 11 , further comprising controlling the treatment condition to determine sizes, morphology, stoichiometry, composition, and phase of the metal oxide nanostructures. 
     
     
         13 . The method of  claim 12 , wherein the phase of the metal oxides nanostructures comprises thermally stable stoichiometric oxides and hydroxides. 
     
     
         14 . The method of  claim 1 , further comprising heating the water, the metallic material, or both of them. 
     
     
         15 . The method of  claim 1 , wherein the step of treating the metallic material with the hot water is assisted by external physical and chemical factors including radiation, applied electric or magnetic fields, mechanical vibrations, and chemical additives. 
     
     
         16 . The method of  claim 15 , wherein the radiation includes microwave, laser, ultraviolet and infrared light, and the chemical additives include metal salt and metal salt solution. 
     
     
         17 . The method of  claim 1 , further comprising activating the surface of the metallic material with a pretreatment physical method and/or a pretreatment chemical method so as to enhance formation kinetics of the metal oxide nanostructures during the hot water process. 
     
     
         18 . The method of  claim 17 , wherein the pretreatment chemical method includes acid dipping, or plasma exposure, and the pretreatment physical method includes roughening the surface of the metallic material by polishing, abrasive blasting, and/or a mechanical erosion process. 
     
     
         19 . The method of  claim 1 , further comprising, prior to the step of treating the metallic material with the hot water, performing surface patterning and/or roughening on the metallic material, so as to form a hierarchically micro-nano-structured metallic material with a surface area that is substantially higher than the high surface area of the treated metallic material. 
     
     
         20 . The method of  claim 1 , wherein the hot water process produces a solution containing metal oxide molecules, usable for other purposes in addition to metal oxide nanostructure growth. 
     
     
         21 . A nanostructured metallic material formed by the method of  claim 1 . 
     
     
         22 . A method of depositing metal oxide nanostructures on a target material, comprising:
 applying a hot water process to a source metallic material and the target material, comprising treating the source metallic material and the target material with hot water under a treatment condition for a period of time so as to form metal oxide nanostructures on a surface of the target material.   
     
     
         23 . The method of  claim 22 , wherein the source metallic material comprises one or more metallic compositions including elemental metals, alloys, compounds, a combination thereof, or a combination of metallic and non-metallic materials. 
     
     
         24 . The method of  claim 22 , wherein the target material is a non-metallic material, a metallic material, or a combination thereof. 
     
     
         25 . The method of  claim 22 , wherein the step of treating the source metallic material with the hot water comprises immersing the source metallic material and the target material in the hot water. 
     
     
         26 . The method of  claim 22 , wherein the step of treating the source metallic material with the hot water is assisted by external physical and chemical factors including radiation, applied electric or magnetic fields, mechanical vibrations, and chemical additives. 
     
     
         27 . The method of  claim 26 , wherein the radiation includes microwave, laser, ultraviolet and infrared light, and the chemical additives include metal salt and metal salt solution. 
     
     
         28 . The method of  claim 22 , further comprising activating the surface of the target material with a pretreatment physical method and/or a pretreatment chemical method so as to enhance formation kinetics of the metal oxide nanostructures during the hot water process. 
     
     
         29 . The method of  claim 28 , wherein the pretreatment chemical method includes acid dipping, or plasma exposure, and the pretreatment physical method includes roughening the surface of the metallic material by polishing, abrasive blasting, and/or a mechanical erosion process. 
     
     
         30 . The method of  claim 22 , further comprising, prior to the step of treating the source metallic material with the hot water, performing surface patterning and/or roughening on the target material, so as to form a hierarchically micro-nano-structured metallic material with a surface area that is substantially higher than the high surface area of the treated target material. 
     
     
         31 . The method of  claim 22 , wherein the hot water process produces a solution containing metal oxide molecules, usable for other purposes in addition to metal oxide nanostructure growth. 
     
     
         32 . The method of  claim 22 , wherein the formation of the metal oxide nanostructures on the surface of the target material metal comprises metal oxide formation on a surface of source metallic material, release of metal oxide molecules from the source metallic material, migration of the metal oxide molecules through water, and deposition of the metal oxide molecules on the surface of the target material, and surface diffusion of the metal oxide molecules so as to form the metal oxide nanostructures with smooth crystal facets on the surface of the target material.