Production Of Chain Agglomerations Of Nano-Scale Metal Particles

Abstract

A process and apparatus for producing chain agglomerations of nano-scale metal particles includes feeding at least one decomposable moiety selected from the group consisting of organometallic compounds, metal complexes, metal coordination compounds and mixtures thereof into a reactor vessel; exposing the decomposable moiety to a source of energy sufficient to decompose the moiety and produce nano-scale metal particles; and deposit or collection of chain agglomerations of nano-scale metal particles.

1 . A process for producing chain agglomerations of nano-scale metal particles, comprising:
 a) providing a reactor vessel having a resistance heater positioned therein;   b) feeding into the reactor vessel at least one decomposable moiety comprising a transition metal comprising cobalt, alone or in mixtures or combinations with iron, nickel or noble metals, the decomposable moiety selected from the group consisting of organometallic compounds, metal complexes, metal coordination compounds and mixtures thereof;   c) heating the resistance heater to a temperature sufficient to decompose the moiety, but no greater than about 500° C.; and   d) exposing the decomposable moiety to the resistance heater, such that the resistance heater provides a point of contact for the decomposition of the decomposable moiety to form nano-scale transition metal particles on said resistance heater after which decomposition occurs on the previously formed particles to produce at least one chain agglomeration of nano-scale metal particles, wherein the nano-scale metal particles have an average diameter no greater than 250 nm and an aspect ratio of 1.4 or less, and the chain agglomerations have an aspect ratio of at least 700:1.   
     
     
         2 . The process of  claim 1 , wherein the temperature of the resistance heater is no greater than about 250° C. 
     
     
         3 . The process of  claim 2 , wherein a vacuum is maintained within the reactor vessel of no less than 1 mm Hg. 
     
     
         4 . (canceled) 
     
     
         5 . The process of  claim 1 , wherein the nano-scale metal particles are deposited on a support. 
     
     
         6 . The process of  claim 1 , wherein a support or collector is positioned within the reactor vessel. 
     
     
         7 . The process of  claim 1 , wherein oxygen is fed into the reactor vessel to partially oxidize the nano-scale metal particles produced by decomposition of the decomposable moiety. 
     
     
         8 . The process of  claim 1 , wherein a reducing material is fed into the reactor vessel to reduce the potential for oxidation of the decomposable moiety. 
     
     
         9 - 10 . (canceled) 
     
     
         11 . The process of  claim 1 , wherein the pressure of the moiety is no greater than 80 mm Hg. 
     
     
         12 . The process of  claim 11 , which further comprises feeding an inert gas into the reactor vessel at a partial pressure of less than  700  mm Hg. 
     
     
         13 - 14 . (canceled) 
     
     
         15 . The process of  claim 1 , wherein the at least one decomposable moiety comprises a metal carbonyl. 
     
     
         16 . The process of  claim 1  wherein the reactor vessel is maintained at a pressure of no less than 1 mm Hg.