Intermetallic catalyst and method for preparing the same
Disclosed is a method of preparing an intermetallic catalyst that includes irradiating ultrasonic waves to a precursor admixture including a noble metal precursor, a transition metal precursor, and a carrier to form core-shell particles including a transition metal oxide coating layer; the annealing the core-shell particles to form intermetallic particles including a transition metal oxide coating layer; and the removing the transition metal oxide coating layer from the intermetallic particles.
1. A method of preparing an intermetallic catalyst, comprising:
forming core-shell particles comprising a transition metal oxide coating layer,
treating the core-shell particles to form intermetallic particles including a transition metal oxide coating layer; and
removing the transition metal oxide coating layer from the intermetallic particles.
2. The method of claim 1 wherein the core shell particles are formed by one or more steps comprising treating a precursor admixture comprising a noble metal precursor and a transition metal precursor with ultrasonic waves.
3. The method of claim 2 wherein the precursor admixture further comprises a carrier.
4. The method of claim 1 , 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.
5. The method of claim 4 , wherein the transition metal in the transition metal oxide coating layer and the transition metal in the transition metal core are the same transition metal derived from the transition metal precursor.
6. The method of claim 1 , wherein a thickness of the transition metal oxide coating layer is about 0.2 nm to about 0.88 nm.
7. The method of claim 2 , wherein the noble metal comprises one or more selected from the group consisting of platinum (Pt), ruthenium (Ru), osmium (Os), iridium (Ir), palladium (Pd), and an alloy thereof.
8. The method of claim 2 , wherein the transition metal comprises one or more selected from the group consisting of 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), and an alloy thereof.
9. The method of claim 3 , wherein the carrier comprises one or more selected from the group consisting of carbon black, graphite, a carbon nanofiber, a graphitized carbon nanofiber, a carbon nanotube, a carbon nanohorn, and a carbon nanowire.
10. The method of claim 2 , wherein the treating with the ultrasonic waves is performed for about 20 minutes to about 4 hours at an output of about 125 W to about 200 W based on 100 mL of the precursor admixture.
11. The method of claim 2 , wherein each of the intermetallic particles comprises
an intermetallic core comprising a transition metal and a noble metal, and
a transition metal oxide coating layer surrounding the intermetallic core.
12. The method of claim 1 , wherein the treating of the core shell particles comprises annealing performed at a temperature of about 700° C. to about 1200° C. for about 0.5 hours to about 16 hours.
13. (Currently Amended The method of claim 12 wherein:
the 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.
14. The method of claim 1 , wherein the removing of the transition metal oxide coating layer from the intermetallic particles is performed by acid treatment.
15. The method of claim 14 , wherein the acid treatment is performed at a temperature of about 60° C. to about 94° C. for about 2 hours to about 4 hours and the acid used for the acid treatment comprises HClO 4 , HNO 3 , HCl, or a combination thereof, and the acid concentration is about 0.01 M to about 1.0 M.
16. An intermetallic catalyst comprising:
an intermetallic core of a transition metal and a noble metal, and
a noble metal skin layer surrounding the intermetallic core.
17. The intermetallic catalyst of claim 16 , wherein in the intermetallic catalyst, an atomic ratio of the noble metal and the transition metal is about 1:0.5 to about 1:2.0.
18. The intermetallic catalyst of claim 16 , wherein a particle diameter of the intermetallic catalyst is about 3.5 nm to about 20 nm.
19. The intermetallic catalyst of claim 16 , wherein a thickness of the noble metal shell is less than or equal to about 0.5 nm.
20. The intermetallic catalyst of claim 16 , wherein the intermetallic core has a degree of ordering of atomic arrangement of greater than or equal to about 30%.