Catalyst coating of a perovskite film and particles exsoluted from the perovskite film
A hybrid catalyst coating composed of a conformal thin film with exsoluted PrO x nano-particles. The conformal PNM thin film can be a perovskite composition of PrNi 0.5 Mn 0.5 O 3 (PNM). The PrO x nano-particles dramatically enhance the oxygen reduction reaction kinetics via a high concentration of oxygen vacancies while the thin PNM film effectively suppresses strontium segregation from the cathode of an intermediate-temperature solid oxide fuel cell.
1. An electrode comprising:
a mixed ionic-electronic conductor; and
an oxygen-reducing catalyst coating on at least a portion of the conductor;
wherein the catalyst coating comprises a conformal perovskite film and particles exsoluted from the perovskite film;
wherein at 750° C., the electrode has a polarization resistance of less than 0.068 Ωcm 2 ; and
wherein the catalyst coating has a thickness in a range from about 1 to about 20 nm.
2. The electrode of claim 1 , wherein the conformal perovskite film comprises a composition comprising praseodymium, oxygen, at least two transition metals.
3. The electrode of claim 2 , wherein the composition further comprises an alkaline earth metal selected from the group consisting of calcium, strontium, and barium;
wherein one of the transition metals is manganese; and
wherein another of the transition metals is selected from the group consisting of nickel, cobalt, and iron.
4. The electrode of claim 3 , wherein the conformal perovskite film comprises Pr 2-x B x Ni y Mn 1-y O 4+δ ;
wherein 0≤δ≤1;
wherein 0≤x≤2; and
wherein 0≤y≤1.
5. The electrode of claim 4 , wherein the B is replaced by an element selected from the group consisting of calcium, strontium, and barium.
6. The electrode of claim 1 , wherein the particles exsoluted from the perovskite film comprise PrO x nano-particles.
7. The electrode of claim 6 , wherein the particles exsoluted from the perovskite film comprise particles selected from the group consisting of PrO 2 nano-particles and Pr 7 O 12 nano-particles.
8. The electrode of claim 1 , wherein the catalyst coating has a thickness in a range from about 1 to about 10 nm.
9. The electrode of claim 1 , wherein the conformal perovskite film comprises a composition selected from the group consisting of PrNi 0.5 Mn 0.5 O 3 and Pr 2 Ni 0.5 Mn 0.5 O 4 .
10. A solid oxide fuel cell comprising:
an anode;
a cathode comprising the electrode of claim 1 ; and
an electrolyte adjacent the anode and the catalyst coating of the cathode.
11. The solid oxide fuel cell of claim 10 , wherein the catalyst coating has a thickness of about 10 nm.
12. The solid oxide fuel cell of claim 10 , wherein the cathode has a peak power density of greater than 0.88 W/cm 2 ; and
wherein the cathode has a surface exchange coefficient of greater than 5.7×10 −4 cm/s.
13. The electrode of claim 1 , wherein the electrode has a peak power density of greater than 0.88 W/cm 2 .
14. The electrode of claim 1 , wherein the electrode has a surface exchange coefficient of greater than 5.7×10 −4 cm/s.
15. An electrode comprising:
a mixed ionic-electronic conductor; and
an oxygen-reducing catalyst coating on at least a portion of the conductor;
wherein the catalyst coating comprises a conformal perovskite film and particles exsoluted from the perovskite film;
wherein the catalyst coating has a thickness in a range from about 1 to about 20 nm; and
wherein the electrode has a surface exchange coefficient of greater than 5.7×10 −4 cm/s.
16. The electrode of claim 15 , wherein at 750° C., the electrode has a polarization resistance of less than 0.068 Ωcm 2 .
17. The electrode of claim 15 , wherein the conformal perovskite film comprises a composition comprising praseodymium, oxygen, at least two transition metals.
18. The electrode of claim 17 , wherein the composition further comprises an alkaline earth metal selected from the group consisting of calcium, strontium, and barium;
wherein one of the transition metals is manganese; and
wherein another of the transition metals is selected from the group consisting of nickel, cobalt, and iron.
19. The electrode of claim 18 , wherein the conformal perovskite film comprises Pr 2-x B x Ni y Mn 1-y O 4+δ ;
wherein 0≤δ≤1;
wherein 0≤x≤2; and
wherein 0≤y≤1.
20. The electrode of claim 19 , wherein the B is replaced by an element selected from the group consisting of calcium, strontium, and barium.
21. The electrode of claim 15 , wherein the particles exsoluted from the perovskite film comprise PrO x nano-particles.
22. The electrode of claim 21 , wherein the particles exsoluted from the perovskite film comprise particles selected from the group consisting of PrO 2 nano-particles and Pr 7 O 12 nano-particles.
23. The electrode of claim 15 , wherein the catalyst coating has a thickness in a range from about 1 to about 10 nm.
24. The electrode of claim 15 , wherein the conformal perovskite film comprises a composition selected from the group consisting of PrNi 0.5 Mn 0.5 O 3 and Pr 2 Ni 0.5 Mn 0.5 O 4 .
25. The electrode of claim 15 , wherein the electrode has a peak power density of greater than 0.88 W/cm 2 .
26. A solid oxide fuel cell comprising:
an anode;
a cathode comprising the electrode of claim 15 ; and
an electrolyte adjacent the anode and the catalyst coating of the cathode.
27. The solid oxide fuel cell of claim 26 , wherein the catalyst coating has a thickness of about 10 nm.
28. The solid oxide fuel cell of claim 26 , wherein the cathode has a peak power density of greater than 0.88 W/cm 2 ; and
wherein the cathode has a surface exchange coefficient of greater than 5.7×10 −4 cm/s.
29. An electrode comprising:
a mixed ionic-electronic conductor comprising lanthanum strontium cobalt ferrite (LSCF); and
an oxygen-reducing catalyst coating introduced on at least a portion of the conductor via solution infiltration;
wherein the catalyst coating comprises a conformal perovskite film and particles exsoluted from the perovskite film;
wherein at 750° C., the electrode has a polarization resistance of less than 0.068 Ωcm 2 ;
wherein the electrode has a peak power density of greater than 0.88 W/cm 2 ;
wherein the electrode has a surface exchange coefficient of greater than 5.7×10 −4 cm/s; and
wherein the catalyst coating has a thickness in a range from about 1 to about 50 nm.
30. The electrode of claim 29 , wherein the catalyst coating is a conformal perovskite film of PrNi 0.5 Mn 0.5 O 3 coating decomposed from Pr 2 Ni 0.5 Mn 0.5 O 4 by nitrite precursors, with the particles comprising exsolved PrO x nano-particles during an annealing process.
31. The electrode of claim 29 , wherein the catalyst coating is a conformal perovskite film of PrNi 0.5 Mn 0.5 O 3 with the particles comprising exsolved PrO x nano-particles; and
wherein the catalyst coating has a thickness in a range from about 1 to about 20 nm.
32. The electrode of claim 29 , wherein the conformal perovskite film comprises a composition comprising:
praseodymium;
oxygen;
manganese;
at least one other transition metal selected from the group consisting of nickel, cobalt, and iron; and
an alkaline earth metal selected from the group consisting of calcium, strontium, and barium.
33. The electrode of claim 32 , wherein the conformal perovskite film comprises Pr 2-x B x Ni y Mn 1-y O 4+δ ;
wherein 0≤δ≤1;
wherein 0≤x≤2; and
wherein 0≤y≤1.