COMPOSITION

• US 20200129959A1
• Filed: 09/17/2019
• Published: 04/30/2020
• Est. Priority Date: 09/18/2018
• Status: Active Grant

• Current Assignee: Ilika Technologies Limited (Ilika Plc)
• Original Assignee: Ilika Technologies Limited (Ilika Plc)
• Inventors: HAYDEN, Brian Elliott, VIAN, Christopher, BRADLEY, Kieren, JUNGIUS, Hugo, GIAGLOGLOU, Kyriakos
• Granted Patent: US 11,471,860 B2
• Time in Patent Office: Days
• CPC Class Codes: B01J 23/002 Mixed oxides other than spinels, e.g. perovskite
• CPC Class Codes: B01J 23/34 Manganese
• CPC Class Codes: B01J 2523/00 Constitutive chemical elements of heterogeneous catalysts
• CPC Class Codes: B01J 2523/17 Copper
• CPC Class Codes: B01J 2523/23 Calcium
• CPC Class Codes: B01J 2523/3706 Lanthanum
• CPC Class Codes: B01J 2523/72 Manganese
• CPC Class Codes: B01J 2523/847 Nickel
• CPC Class Codes: B01J 35/393 Metal or metal oxide crystallite size
• CPC Class Codes: B01J 35/397 Egg shell like
• CPC Class Codes: B01J 35/398 Egg yolk like
• CPC Class Codes: B01J 35/58 Fabrics or filaments
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C01G 45/1264 containing rare earth, e.g. La1-xCaxMnO3, LaMnO3
• CPC Class Codes: C01G 53/70 containing rare earth, e.g. LaNiO3 C01G53/68 takes precedence
• CPC Class Codes: C01P 2002/34 perovskite-type (ABO3)
• CPC Class Codes: C01P 2002/54 one element only
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2002/76 by a space-group or by other symmetry indications
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C01P 2006/40 : Electric properties
• CPC Class Codes: H01M 4/8652 : as mixture
• CPC Class Codes: H01M 4/9033 : Complex oxides, optionally doped, of the type M1MeO3, M1 being an alkaline earth metal or a rare earth, Me being a metal, e.g. perovskites
• CPC Class Codes: H01M 4/9041 : Metals or alloys H01M4/92 takes precedence
• CPC Class Codes: Y02E 60/50 : Fuel cells

Abstract

A composition consisting essentially of a perovskite crystalline structure, the composition comprising: ions of a first metal M¹ which occupies an A-site of the perovskite crystalline structure; ions of a second metal M² which occupies a B-site of the perovskite crystalline structure, M² having two oxidation states capable of forming a redox couple suitable for reversibly catalyzing an oxygen reduction reaction (ORR) and an oxygen evolution reaction (OER); ions of a third metal M³ at least a portion of which substitutes for M¹ in the A-site of the perovskite crystalline structure, and at least a portion of which optionally also substitutes for M² in the B-site of the perovskite crystalline structure, at least some of the atoms M³ having a different oxidation state to the atoms M¹; and atoms of an element X, which is a chalcogen; wherein the metal ions M¹, M² and M³ are present in the atomic ratios (a) or (b): (a) 25 to 49.9 atomic % M¹, 30 to 60 atomic % M², and 5 to 45 atomic % M³; (b) 10 to 30 atomic % M¹, 50.1 to 60 atomic % M², and 25 to 45 atomic % M³; each expressed as a percentage of the total metal ions in the composition excluding oxygen; wherein the presence of the M³ ions causes a change in the oxidation state of some of the M² ions in the structure, thereby creating the redox couple suitable for reversibly catalyzing the ORR and OER.

Claims

1. A composition consisting essentially of a perovskite crystalline structure, the composition comprising:

ions of a first metal M¹ which occupies an A-site of the perovskite crystalline structure;

ions of a second metal M² which occupies a B-site of the perovskite crystalline structure, M² having two oxidation states capable of forming a redox couple suitable for reversibly catalyzing an oxygen reduction reaction (ORR) and an oxygen evolution reaction (OER);

ions of a third metal M³, at least a portion of which substitutes for M¹ in the A-site of the perovskite crystalline structure, and at least a portion of which optionally also substitutes for M² in the B-site of the perovskite crystalline structure, at least some of the atoms M³ having a different oxidation state to the atoms M¹; and

atoms of an element X, which is a chalcogen;

wherein the metal ions M¹, M² and M³ are present in atomic ratios within the ranges (a) or (b);

(a) 25 to 49.9 atomic % M¹, 30 to 60 atomic % M², and 5 to 45 atomic % M³;

(b) 10 to 30 atomic % M¹, 50.1 to 60 atomic % M², and 25 to 45 atomic % M³;

each expressed as a percentage of the total metal ions in the composition excluding oxygen;

wherein the presence of the M³ ions causes a change in the oxidation state of some of the M² ions in the structure, thereby creating the redox couple suitable for reversibly catalyzing the ORR and OER.

2. A composition according to claim 1, wherein at least some of the M³ atoms are in an oxidation state which is capable of oxidising some of the M² atoms in the structure, thereby creating the redox couple suitable for reversibly catalyzing the ORR and OER.

3. A composition according to claim 1, wherein the metal ions M¹, M² and M³ are present in the atomic ratios (al):

(a1) 35 to 45 atomic % M¹, 30 to 45 atomic % M², and 15 to 25 atomic % M³;

all expressed as a percentage of the total metal ions in the composition excluding oxygen.

4. A composition according to claim 1, wherein the metal ions M¹, M² and M³ are present in the atomic ratios (b1):

(b1) 15 to 25 atomic % M¹, 51 to 58 atomic % M², and 25 to 35 atomic % M³;

all expressed as a percentage of the total metal ions in the composition excluding oxygen.

5. A composition according to claim 1, wherein M¹ is a trivalent metal.

6. A composition according to claim 5, wherein M¹ is selected from the group consisting of Y, La, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sb and Bi.

7. A composition according to claim 5, wherein M¹ is La.

8. A composition according to claim 1, wherein M² is a trivalent metal capable of oxidation to a tetravalent oxidation state to form the redox couple.

9. A composition according to claim 1, wherein M² is selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Tc, Ru, Rh, Pd, and Ag.

10. A composition according to claim 8, wherein M² is Mn.

11. A composition according to claim 1, wherein M³ is a divalent or trivalent metal.

12. A composition according to claim 1, wherein M³ is selected from the group consisting of Mg, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Tc, Ru, Rh or Pd.

13. A composition according to claim 12, wherein M³ is Ni.

14. A composition according to claim 12, wherein M³ is Ca.

15. A composition according to claim 1, wherein M¹ is La, M² is Mn and M³ is Ni.

16. A composition according to claim 15, wherein the composition comprises 35 to 45 atomic % La, 40 to 45 atomic % Mn, and 15 to 20 atomic % Ni, all expressed as a percentage of the total metal atoms in the composition excluding oxygen.

17. A composition according to claim 1, wherein M¹ is La, M² is Mn and M³ is Ca.

18. A composition according to claim 17, wherein the composition comprises 15 to 25 atomic % La, 51 to 58 atomic % Mn, and 25 to 35 atomic % Ca, all expressed as a percentage of the total metal atoms in the composition excluding oxygen.

19. A composition according to claim 1, which is formed as a nanoparticle.

20. A composition according to claim 19, wherein the nanoparticle is supported on a support.

21. A composition according to claim 1, wherein neither M¹ nor M³ is Sr.

22. A composition according to claim 1, wherein the composition does not have the formula La₁₋

ySr_yZO₃, wherein y is greater than 0 and less than 1, and Z is a transition metal.

23. A composition according to claim 1, wherein the composition does not have the formula La₁₋

ySr_yZO₃, wherein y is greater than 0 and less than 1, and Z is selected from the group consisting of Co, Cu, Fe, Mn, and Ni.

24. A core-shell composition comprising (a) a core particle comprising a first composition;

and (b) a second, different composition applied as a shell on the core particle, wherein either the first or the second composition is a composition according to claim 1.

25. A method of preparing the composition according to claim 1, the method comprises providing a source of each component element of the compound, wherein the sources comprise at least a source of atoms M¹, a source of atoms M², a source of atoms M³, and a source of atoms X;

and depositing the sources of each element onto a substrate, wherein the component elements from the sources react on the substrate to form the composition consisting essentially of the perovskite crystalline structure containing at least M¹, M², M³ and X.

26. A method according to claim 25, the method comprising forming the crystalline composition in the form of a film on the substrate.

27. A method of using a composition, comprising:

providing the composition according to claim 1;

using the composition as a catalyst.

28. The method according to claim 27, wherein the catalyst catalyses the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER).

29. An electrode comprising the composition according to claim 1.

30. A cell comprising:

an anode;

a cathode;

an electrolyte;

wherein the anode and/or the cathode includes a catalyst comprising a composition according to claim 1.

31. A cell according to claim 30, which is a fuel cell.

32. A cell according to claim 31, which is a regenerative fuel cell.

33. A cell according to claim 31, which is an alkaline fuel cell.

34. A cell according to claim 30, which is a metal-air cell.