Noble metal-based electrocatalyst and method of treating a noble metal-based electrocatalyst
View Patent ↗A noble metal-based electrocatalyst comprises a bimetallic particle comprising a noble metal and a non-noble metal and having a polyhedral shape. The bimetallic particle comprises a surface-segregated composition where an atomic ratio of the noble metal to the non-noble metal is higher in a surface region and in a core region than in a sub-surface region between the surface and core regions. A method of treating a noble metal-based electrocatalyst comprises annealing a bimetallic particle comprising a noble metal and a non-noble metal and having a polyhedral shape at a temperature in the range of from about 100° C. to about 1100° C.
1. A noble metal-based electrocatalyst comprising:
a bimetallic particle comprising a noble metal and a non-noble metal and having a polyhedral shape, the bimetallic particle comprising a surface-segregated composition where an atomic ratio of the noble metal to the non-noble metal is higher in a surface region and in a core region than in a sub-surface region between the surface and core regions,
wherein the core region has a size of from about 40% to about 60% of a size of the bimetallic particle, wherein the surface region has a thickness of from about 10% to about 30% of the size of the bimetallic particle, and wherein the sub-surface region has a thickness of from about 10% to about 50% of the size of the bimetallic particle.
2. The noble metal-based electrocatalyst of claim 1 further comprising a plurality of the bimetallic particles.
3. The noble metal-based electrocatalyst of claim 2 , wherein the bimetallic particles are agglomerated.
4. The noble metal-based electrocatalyst of claim 2 , wherein the bimetallic particles are non-agglomerated.
5. The noble metal-based electrocatalyst of claim 2 , further comprising a support underlying the bimetallic particles, the bimetallic particles being dispersed on the support.
6. The noble metal-based electrocatalyst of claim 1 , wherein the bimetallic particle has a size of at least about 10 nm.
7. The noble metal-based electrocatalyst of claim 1 , wherein the polyhedral shape is selected from the group consisting of: cube, truncated octahedron, octahedron, truncated tetrahedron, tetrahedron, and icosahedron.
8. The noble metal-based electrocatalyst of claim 1 , wherein the noble metal is selected from the group consisting of: Pt, Pd, Au, Ag, Ru, Rh, Os, and Ir, and wherein the non-noble metal is selected from the group consisting of: Ti, V, Cr, Mn, Mo, Zr, Nb, Ta, Zn, In, Sn, Sb, Pb, W, Co, Cu, Ni and Fe.
9. The noble metal-based electrocatalyst of claim 8 , wherein the noble metal comprises Pt and the non-noble metal comprises Ni.
10. The noble metal-based electrocatalyst of claim 1 , wherein an atomic ratio of the noble metal to the non-noble metal in the surface region and in the core region is from 0.5 to about 4.
11. The noble metal-based electrocatalyst of claim 1 , wherein the atomic ratio of the noble metal to the non-noble metal in the sub-surface region is from about 0.2 to about 3.
12. The noble metal-based electrocatalyst of claim 1 , wherein the polyhedral shape comprises {111} facets.