Controlled electrodeposition of nanoparticles

Abstract

Deposition of nanoparticles onto carbon surfaces is described. Metal and/or metal oxide ions are deposited on a carbon surface by electrodeposition, such as by immersing a carbon and an anode in a salt bath, and applying a number of electrical pulses having a defined pulse width. The size, coverage density, and metallic composition of the nanoparticles may be affected by the pulse width of the electrical pulses, the number of electrical pulses, and the chemical composition of the salt bath, respectively. The carbon may be anodized before electrodeposition. If the carbon is a carbon precursor, after electrodeposition, the carbon precursor is carbonized to form a carbon. After electrodeposition, the carbon may be activated to form an activated carbon. The nanoparticles may serve as catalysts for activation rugosity of mesoporous carbons. The catalytically activated carbon materials may be used in all manner of devices that contain carbon materials.

1 . A method of forming metallic nanoparticles on the surface of a carbon, comprising:
 electrodepositing metal ions on the surface of the carbon, the electrodepositing comprising:   applying a plurality of electrical pulses, each electrical pulse having a pulse width, wherein the number of electrical pulses is between 5 and 50, and the pulse width is between 5 milliseconds and 200 milliseconds.   
   
   
       2 . The method of  claim 1 , wherein the carbon is a carbon precursor. 
   
   
       3 . The method of  claim 2 , wherein the carbon precursor is conductive. 
   
   
       4 . The method of  claim 1 , wherein electrodepositing metal ions further comprises immersing the carbon and an anode in a salt bath having a chemistry, wherein the metallic nanoparticle composition is determined by the chemistry of the salt bath. 
   
   
       5 . The method of  claim 1 , wherein the nanoparticles comprise at least one of: nickel or iron. 
   
   
       6 . The method of  claim 1 , wherein the nanoparticles are less than D 50  50 nm. 
   
   
       7 . The method of  claim 1 , wherein the pulse duration is less than 50 milliseconds. 
   
   
       8 . The method of  claim 1 , wherein the number of electrical pulses is less than 30. 
   
   
       9 . The method of  claim 1 , further comprising anodizing the carbon before electrodepositing metal ions. 
   
   
       10 . A method comprising:
 electrodepositing metal ions on a surface of a carbon, to form metallic nanoparticles on the surface of the carbon; and   activating the carbon to form an activated carbon.   
   
   
       11 . The method of  claim 10 , wherein the carbon is a carbon precursor. 
   
   
       12 . The method of  claim 11 , wherein the carbon precursor is conductive. 
   
   
       13 . The method of  claim 11 , further comprising carbonizing the precursor to form a carbon. 
   
   
       14 . The method of  claim 10 , wherein electrodepositing metal ions further comprises immersing the carbon and an anode in a salt bath having a chemistry, wherein the metallic nanoparticle composition is determined by the chemistry of the salt bath. 
   
   
       15 . The method of  claim 10 , wherein the nanoparticles comprise at least one of: nickel or iron. 
   
   
       16 . The method of  claim 10 , wherein the nanoparticles are less than D 50  50 nm. 
   
   
       17 . The method of  claim 10 , wherein the pulse duration is less than 50 milliseconds. 
   
   
       18 . The method of  claim 10 , wherein the number of electrical pulses is less than 30. 
   
   
       19 . A method of forming an activated carbon:
 (a) providing a carbon which is either a carbon or a carbon precursor;   (b) electrodepositing metal ions on the surface of the carbon to form nanoparticles on the surface of the carbon;   (b2) if the carbon is a carbon precursor, then carbonizing the precursor to form a carbon; and   (c) activating the carbon to form an activated carbon.   
   
   
       20 . The method of  claim 19 , wherein activating the carbon comprises:
 catalytically activating the carbon in air and an inert gas to form a catalytically activated carbon; wherein the mass of the catalytically activated carbon is lower than the mass of the carbon; and   physically activating the catalytically activated carbon in steam or carbon dioxide to form an activated carbon; wherein the mass of the activated carbon is lower than the mass of the catalytically activated carbon and wherein the activated carbon is mesoporous.   
   
   
       21 . The method of  claim 19  wherein the nanoparticles comprise at least two different metal oxides. 
   
   
       22 . The method of  claim 19  wherein the nanoparticles comprise at least one of: iron, nickel, cobalt, titanium, ruthenium, osmium, rhodium, iridium, yttrium, palladium, or platinum.