Electrochemical Synthesis of Elongated Noble Metal Nanoparticles, such as Nanowires and Nanorods, on High-Surface Area Carbon Supports

Abstract

Elongated noble-metal nanoparticles and methods for their manufacture are disclosed. The method involves the formation of a plurality of elongated noble-metal nanoparticles by electrochemical deposition of the noble metal on a high surface area carbon support, such as carbon nanoparticles. Prior to electrochemical deposition, the carbon support may be functionalized by oxidation, thus making the manufacturing process simple and cost-effective. The generated elongated nanoparticles are covalently bound to the carbon support and can be used directly in electrocatalysis. The process provides elongated noble-metal nanoparticles with high catalytic activities and improved durability in combination with high catalyst utilization since the nanoparticles are deposited and covalently bound to the carbon support in their final position and will not change in forming an electrode assembly.

1 . A catalyst particle comprising:
 a carbon support having a high surface area per unit mass; and   an elongated metal nanoparticle covalently bound to the carbon support.   
     
     
         2 . The catalyst particle of  claim 1 , wherein the elongated metal nanoparticle has a morphology of a nanowire or a nanorod. 
     
     
         3 . The catalyst particle of  claim 1 , wherein the elongated metal nanoparticle comprises Pd. 
     
     
         4 . The catalyst particle of  claim 1 , wherein the elongated metal nanoparticle comprises a continuous and nonporous shell with a solid core. 
     
     
         5 . The catalyst particle of  claim 1 , wherein the carbon support is functionalized. 
     
     
         6 . The catalyst particle of  claim 5 , wherein the functionalized carbon support comprises a plurality of carbon nanoparticles having exposed on the surface a functional group selected from carboxylic, carbonyl, phenol, lactone or a combination thereof. 
     
     
         7 . The catalyst particle of  claim 4 , wherein the shell is more noble than the core. 
     
     
         8 . The catalyst particle of  claim 7 , wherein the elongated metal nanoparticle comprises a Pd core and a Pt shell. 
     
     
         9 . The catalyst particle of  claim 4 , wherein the shell comprises 4 to 12 monolayers of platinum (Pt). 
     
     
         10 . An electrode comprising:
 a carbon support having a high surface area per unit mass; and   an elongated metal nanoparticle covalently bound to the carbon support.   
     
     
         11 . The electrode of  claim 10 , wherein the elongated metal nanoparticle has a morphology of a nanowire or a nanorod. 
     
     
         12 . The electrode of  claim 10 , wherein the elongated metal nanoparticle comprises Pd. 
     
     
         13 . The electrode of  claim 10 , wherein the elongated metal nanoparticle comprises a continuous and nonporous shell with a solid core. 
     
     
         14 . The electrode of  claim 10 , wherein the carbon support is functionalized. 
     
     
         15 . The electrode of  claim 14 , wherein the functionalized carbon support comprises a plurality of carbon nanoparticles having exposed on the surface a functional group selected from carboxylic, carbonyl, phenol lactone or a combination thereof. 
     
     
         16 . The electrode of  claim 13 , the shell is more noble than the core. 
     
     
         17 . The electrode of  claim 16 , wherein the elongated metal nanoparticle comprises a Pd core and a Pt shell. 
     
     
         18 . An energy conversion device comprising:
 a first electrode;   a conducting electrolyte; and   a second electrode,   wherein at least one of the first or second electrodes comprises a plurality of catalyst particles of  claim 1 .   
     
     
         19 . The energy conversion device of  claim 18 , wherein the elongated metal nanoparticle has a morphology of a nanowire or a nanorod. 
     
     
         20 . The energy conversion device of  claim 18 . wherein the elongated metal nanoparticle comprises Pd. 
     
     
         21 . The energy conversion device of  claim 18 , wherein the elongated metal nanoparticle comprises a palladium (Pd) core and platinum (Pt) shell having a shape of a nanowire or a nanorod with an external diameter of 3 nm to 9 nm.