Method and device to synthesize boron nitride nanotubes and related nanoparticles

Abstract

Methods and apparatus for producing chemical nanostructures having multiple elements, such as boron and nitride, e.g. boron nitride nanotubes, are disclosed. The method comprises creating a plasma jet, or plume, such as by an arc discharge. The plasma plume is elongated and has a temperature gradient along its length. It extends along its length into a port connector area having ports for introduction of feed materials. The feed materials include the multiple elements, which are introduced separately as fluids or powders at multiple ports along the length of the plasma plume, said ports entering the plasma plume at different temperatures. The method further comprises modifying a temperature at a distal portion of or immediately downstream of said plasma plume; and collecting said chemical nanostructures after said modifying.

1 .- 20 . (canceled) 
     
     
         21 . A method comprising:
 (a) creating a plasma jet having a temperature gradient along its length, wherein the plasma jet comprises a propellant gas;   (b) introducing a boron-containing species at a first point along the length of the plasma jet and introducing a nitrogen-containing species at a second point proximal a region where the plasma jet is created; and   (c) forming boron nitride-based nanostructures due to cooling of the plasma jet.   
     
     
         22 . The method of  claim 21 , wherein the boron nitride-based nanostructures comprise boron nitride nanotubes. 
     
     
         23 . The method of  claim 21 , wherein operation (b) further comprises introducing a carbon-containing species along the length of the plasma jet. 
     
     
         24 . The method of  claim 23 , wherein the carbon-containing species comprises a hydrocarbon or an alcohol. 
     
     
         25 . The method of  claim 21 , wherein the plasma jet is created by an arc discharge between two electrodes. 
     
     
         26 . The method of  claim 21 , wherein operation (c) comprises positioning a member downstream of the plasma jet or to contact a distal portion of the plasma jet. 
     
     
         27 . The method of  claim 26 , wherein the member comprises a water-cooled member comprising a water carrying tube which is of a shape that is linear, annular, or serpentine. 
     
     
         28 . The method  claim 21  further comprising:
 (d) collecting the boron nitride-based nanostructures. 
 
     
     
         29 . The method of  claim 21 , wherein the boron nitride-based nanostructures are selected from a group consisting of boron nitride nanotubes, boron nitride spheres, and boron nitride sheets. 
     
     
         30 . The method of  claim 21 , wherein the boron-containing species is selected from a group consisting of elemental born, a boron oxide, a boron sulfide, a boron nitride, and a boron halide. 
     
     
         31 . The method of  claim 21 , wherein the nitrogen-containing species comprises nitrogen gas. 
     
     
         32 . The method of  claim 21 , wherein the propellant gas comprises an inert gas. 
     
     
         33 . The method of  claim 32 , wherein the inert gas is selected from a group consisting of Ar, He, Xe, and a combination thereof. 
     
     
         34 . An apparatus comprising:
 a plasma source configured to generate a plasma jet, the plasma source defining at least one port for the introduction of a first chemical-species proximate a region where the plasma jet is generated;   a port connector connected to the plasma source, the port connector configured to receive the plasma jet, the port connector defining at least one port along its length configured for the introduction of a second chemical-species to the plasma jet; and   a chamber connected to the port connector;   wherein the plasma source comprises a first and a second electrode;   wherein the second electrode is positioned distal to the first electrode and proximal to the port connector;   wherein the first electrode is a conical tip electrode that extends towards an annular opening of the second electrode to form a nozzle; and   wherein the chamber comprises a collection element positioned to collect nanomaterials.   
     
     
         35 . The apparatus of  claim 34 , wherein the plasma source further includes a source of electric potential connected to the two electrodes, wherein the source of electric potential is configured to generate an arc across the two electrodes. 
     
     
         36 . The apparatus of  claim 34 , wherein the collection element comprises a net. 
     
     
         37 . The apparatus of  claim 36 , wherein the net comprises a surface, and wherein the composition of the surface is selected from a group consisting of a metal, a ceramic, and a combination thereof. 
     
     
         38 . The apparatus of  claim 36 , wherein the net comprises honeycomb structures. 
     
     
         39 . The apparatus of  claim 34 , wherein the collection element is positioned perpendicular to the plasma jet. 
     
     
         40 . The apparatus of  claim 34 , wherein the chamber further comprises a quench moderator positioned proximal to the collection element. 
     
     
         41 . The apparatus of  claim 40 , wherein the quench moderator is axially aligned with the collection element. 
     
     
         42 . The apparatus of  claim 40 , wherein the quench moderator is a cooled, inert member proximate the plasma jet and shaped as a linear rod, serpentine rod, or torus. 
     
     
         43 . The apparatus of  claim 40 , wherein the quench moderator is positioned in the plasma jet and configured to allow the plasma jet to pass by the quench moderator. 
     
     
         44 . The apparatus of  claim 34 , wherein the apparatus is configured to form nanomaterials due to cooling of the plasma jet, and wherein the nanomaterials comprise elements of the first and the second chemical-species introduced to the chamber.