Catalyst for fuel cell and method for preparing the same

Abstract

A catalyst for a fuel cell includes: a crystalline carbon support having a specific surface area of about 200 m 2 /g to about 500 m 2 /g; and intermetallic active particles of a transition metal and a noble metal, wherein the intermetallic active particles are supported on the crystalline carbon support and have a particle diameter of greater than or equal to about 3 nm.

What is claimed is: 
     
         1 . A catalyst for a fuel cell, the catalyst comprising:
 a crystalline carbon support having a specific surface area of about 200 m 2 /g to about 500 m 2 /g; and   intermetallic active particles of a transition metal and a noble metal,   wherein the intermetallic active particles are supported on the crystalline carbon support and have a particle diameter of greater than or equal to about 3 nm.   
     
     
         2 . The catalyst of  claim 1 , wherein the crystalline carbon support has a Raman spectrum intensity ratio of (1360) plane and (1590) plane, I G /I D  ((I(1580 cm −1 )/I(1360 cm −1 )) of greater than or equal to about 0.9. 
     
     
         3 . The catalyst of  claim 1 , wherein the crystalline carbon support has an interplanar spacing (d 002 ) of the (002) plane of less than or equal to about 0.355 nm. 
     
     
         4 . The catalyst of  claim 1 , wherein the crystalline carbon support has a carbon shell thickness of about 3 nm to about 6 nm. 
     
     
         5 . The catalyst of  claim 1 , wherein the crystalline carbon support comprises carbon black, graphite, or a combination thereof. 
     
     
         6 . The catalyst of  claim 1 , wherein the catalyst comprises more than about 60% by number of the intermetallic active particles having a particle diameter of greater than or equal to about 3 nm with respect to a total number of the intermetallic active particles. 
     
     
         7 . The catalyst of  claim 1 , wherein the catalyst comprises about 40% or less by number of the intermetallic active particles present in pores of the carbon support with respect to a total number of the intermetallic active particles. 
     
     
         8 . The catalyst of  claim 1 , wherein the catalyst comprises more than 60% by number of the intermetallic active particles participating in catalytic activity with respect to a total number of the intermetallic active particles. 
     
     
         9 . The catalyst of  claim 1 , wherein the intermetallic active particles comprise an intermetallic core of a transition metal and a noble metal, and a noble metal skin layer surrounding the intermetallic core. 
     
     
         10 . The catalyst of  claim 1 , wherein an atomic ratio of the noble metal and the transition metal in the intermetallic active particles is about 1:0.2 to about 1:0.6. 
     
     
         11 . The catalyst of  claim 1 , wherein the noble metal comprises platinum (Pt), ruthenium (Ru), osmium (Os), iridium (Ir), palladium (Pd), an alloy thereof, or a mixture thereof. 
     
     
         12 . The catalyst of  claim 1 , wherein the transition metal comprises cobalt (Co), iron (Fe), nickel (Ni), zinc (Zn), tin (Sn), manganese (Mn), copper (Cu), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), zirconium (Zr), yttrium (Y), niobium (Nb), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), osmium (Os), palladium (Pd), cadmium (Cd), iridium (Ir), gold (Au), silver (Ag), an alloy thereof, or a mixture thereof. 
     
     
         13 . A method of preparing a catalyst for a fuel cell, the method comprising:
 supporting a noble metal and a transition metal on a crystalline carbon support having a specific surface area of about 200 m 2 /g to about 500 m 2 /g; and   annealing the crystalline carbon support on which the noble metal and the transition metal are supported.   
     
     
         14 . The method of  claim 13 , wherein the method further comprises: coating a protective layer on the surface of the crystalline carbon support on which the noble metal and the transition metal are supported before annealing. 
     
     
         15 . The method of  claim 14 , wherein the protective layer is an organic protective layer including polydopamine, polyaniline, polypyrrole, or a combination thereof, or
 an inorganic protective layer including carbon, metal oxide, ceramic, or a combination thereof.   
     
     
         16 . A method of preparing a catalyst for a fuel cell, the method comprising:
 irradiating ultrasonic waves to a precursor mixed solution including a noble metal precursor, a transition metal precursor, and a crystalline carbon support having a specific surface area of about 200 m 2 /g to about 500 m 2 /gm, and forming core-shell particles including a transition metal oxide coating layer;   annealing the core-shell particles and forming intermetallic particles including a transition metal oxide coating layer; and   removing the transition metal oxide coating layer from the intermetallic particles.   
     
     
         17 . The method of  claim 16 , wherein the core-shell particles comprise:
 a transition metal core;   a noble metal shell surrounding the transition metal core; and   a transition metal oxide coating layer surrounding the noble metal shell.   
     
     
         18 . The method of  claim 16 , wherein irradiating of the ultrasonic waves is performed for about 20 minutes to about 2 hours at an output of about 125 W to about 200 W based on 100 mL of the precursor mixed solution. 
     
     
         19 . The method of  claim 16 , wherein the intermetallic particles comprise:
 intermetallic particles of a transition metal and a noble metal; and   a transition metal oxide coating layer surrounding the intermetallic particles.   
     
     
         20 . The method of  claim 13  or  claim 16 , wherein annealing is performed at about 700° C. to about 1200° C. for about 2 hours to about 4 hours. 
     
     
         21 . The method of  claim 13  or  claim 16 , wherein annealing is performed under a mixed gas including hydrogen (H 2 ) and argon (Ar), and
 the mixed gas comprises hydrogen (H 2 ) in an amount of about 1 volume % to about 10 volume % based on a total volume of the mixed gas. 
 
     
     
         22 . The method of  claim 16 , wherein removing the transition metal oxide coating layer from the intermetallic particles is performed by an acid treatment at about 60° C. to about 94° C. for about 2 hours to 4 hours. 
     
     
         23 . The method of  claim 22 , wherein an acid used for the acid treatment comprises HClO 4 , HNO 3 , H 2 SO 4 , HCl, or a combination thereof. 
     
     
         24 . The method of  claim 22 , wherein a concentration of an acid used for the acid treatment is about 0.01 M to about 1.0 M.