Gas phase synthesis of nanoparticles in a multi-element diffusion flame burner

Abstract

Low nanosized combusted products are obtained by introducing at least one volatile metal compound into the flame of a non-premixed, multi-element diffusion flame burner which exhibits a one-dimensional temperature profile. The combustion process generates a stable environment favoring formation of very small particles of uniform composition. Adjusting burner stoichiometry enables production of zero valent metal powders and metal compounds of low or intermediate oxidation states as well as the usual more highly oxidized species.

What is claimed is:  
     
         1 . A process for the generation of low nanosized particles of one or more metals or the combusted products thereof, comprising: 
 a) providing a multi-element diffusion flame burner having a plurality of combustible gas passageways and combusting gas passageways arranged in a geometric array defining a substantially planar burner surface, and optionally, one or a plurality of spaced apart precursor supply passageways;    b) supplying non-premixed combusting gas to said combusting gas passageways and non-premixed combustible gas to said combustible gas passageways and igniting to form a primary flame;    c) introducing a particle precursor into at least one of 
 (i) said combusting gas,  
 (ii) said combustible gas, or  
 (iii) said precursor supply passageways, and  
   d) recovering a nanosized combusted particle product.    
     
     
         2 . The process of  claim 1 , wherein said precursor comprises at least one volatile metal compound of a metal of groups 3 to 7, a transition metal, or an inner transition metal.  
     
     
         3 . The process of  claim 1 , wherein said precursor comprises a volatile metal alkyl, metal alkoxide, metal hydride, metal halide, metal salt of an organic carboxylic acid, metal glycolate, metal olefin complex, or a mixed metal compound containing at least one metal and two or more alkyl, alkoxide, hydride, halide, carboxylate, olefin, or glycolate moieties.  
     
     
         4 . The process of  claim 1 , wherein said metal comprises silicon, titanium, aluminum, zirconium, gold, silver, platinum, or tin.  
     
     
         5 . The process of  claim 1 , wherein said nanosized particles have a mean particle size of less than 50 nm.  
     
     
         6 . The process of  claim 1 , wherein said precursor is an organic tin compound and said nanosized particle product comprises one or more of Sn(0), SnO, or SnO 2 .  
     
     
         7 . The process of  claim 6 , wherein said nanosized particle product comprises Sn(0).  
     
     
         8 . The process of  claim 1 , wherein at least one of said combusting gas or said combustible gas is diluted with an inert gas.  
     
     
         9 . An Sn(0) or SnO nanosized particle product, prepared by the process of  claim 1 .  
     
     
         10 . The process of  claim 1 , further comprising 
 d) altering the flame stoichiometry to vary the oxidation state of said combusted product.