Platinum monolayer on hollow, porous nanoparticles with high surface areas and method of making
View Patent ↗A catalytic nanoparticle includes a porous, hollow core and an atomically thin layer of platinum atoms on the core. The core is a porous palladium, palladium-M or platinum-M core, where M is selected from the group consisting of gold, iridium, osmium, palladium, rhenium, rhodium and ruthenium.
1. A catalytic nanoparticle comprising:
a porous, hollow palladium, palladium-M or platinum-M core, where M is selected from the group consisting of gold, iridium, osmium, palladium, rhenium, rhodium and ruthenium; and
an atomically thin layer of platinum atoms on the core.
2. The catalytic nanoparticle of claim 1 wherein a lattice constant of the porous, hollow palladium core is less than that of bulk palladium.
3. The catalytic nanoparticle of claim 1 wherein a lattice constant of the porous, hollow platinum-M core is less than that of bulk platinum-M.
4. The catalytic nanoparticle of claim 1 wherein core has pores between about 1 nanometer and about 5 nanometers.
5. The catalytic nanoparticle of claim 1 wherein the core has a diameter between about 2 nanometers and about 20 nanometers.
6. The catalytic nanoparticle of claim 1 wherein the atomically thin layer of platinum atoms is selected from the group consisting of a monolayer, a bilayer and a trilayer of platinum metal atoms.
7. The catalytic nanoparticle of claim 1 , wherein the porous, hollow platinum-M core has a platinum:M mole ratio between about 1:2 and about 1:12.
8. The catalytic nanoparticle of claim 1 , wherein the porous, hollow platinum-M core has a platinum:M mole ratio between about 1:3 and about 1:6.
9. A method for forming a catalytic structure, the method comprising:
forming non-noble transition metal nanoparticles;
replacing non-noble transition metal atoms of the non-noble transition metal nanoparticles with palladium, palladium-M or platinum-M alloy atoms, where M is selected from the group consisting of gold, iridium, osmium, palladium, rhenium, rhodium and ruthenium, to form a porous, hollow palladium, palladium-M or platinum-M core; and
depositing an atomically thin layer of platinum atoms on the porous, hollow core.
10. The method of claim 9 wherein the non-noble transition metal nanoparticles are copper nanoparticles.
11. The method of claim 10 wherein the porous, hollow core has pores with a pore size between about 1 nanometer and about 5 nanometers.
12. The method of claim 10 wherein the porous, hollow core has a diameter between about 2 nanometers and about 20 nanometers.
13. The method of claim 10 wherein the core is formed from platinum-M alloy having a platinum:M mole ratio between about 1:2 to about 1:12.
14. The method of claim 9 wherein the non-noble transition metal nanoparticles have a lattice constant smaller than the lattice constant of platinum.
15. The method of claim 9 wherein the non-noble transition metal nanoparticles have a diameter between about 1 nanometer and about 20 nanometers.
16. The method of claim 9 wherein the step of depositing a monolayer of platinum atoms comprises:
depositing a copper monolayer on the porous, hollow core; and
replacing the copper monolayer with the monolayer of platinum atoms.
17. The method of claim 9 wherein the step of depositing a monolayer of platinum atoms is repeated to form a bilayer or a trilayer of platinum atoms.
18. The method of claim 9 wherein the step of replacing the non-noble transition metal atoms comprises:
mixing the non-noble transition metal nanoparticles with a solution containing a palladium salt or a palladium-M alloy salt.
19. The method of claim 9 wherein the step of replacing the non-noble transition metal atoms comprises:
mixing the non-noble transition metal nanoparticles with a solution containing a platinum-M alloy salt.
20. The method of claim 19 wherein the step of mixing the non-noble transition metal nanoparticles with a solution containing a platinum-M alloy salt comprises:
forming a solution having a platinum-M alloy concentration such that when the non-noble transition metal nanoparticles are added to the solution the platinum-M:non-noble transition metal is about 1:1.