Mesoporous nickel-iron-manganese-alloy based metal/metal oxide composite thick film catalysts

Patent metadata

Field	Value
Publication number	US-2018351155-A1
Application number	US-201815990650-A
Country	US
Kind code	A1
Filing date	May 27, 2018
Priority date	Nov 29, 2015
Publication date	Dec 6, 2018
Grant date	—

Abstract

Selective alloy corrosion is used to synthesize a robust and ultrafine mesoporous NiFeMn-based metal/metal oxide oxygen evolving catalyst with ligament and pore sizes in the range of 10 nm and a BET surface area of 43 m2/g. As an oxygen evolving catalyst, the mesoporous catalyst exhibits high stability (>264 hours) at a high current density (500 mA/cm2) with a low overpotential (360 mV) using a moderate electrolyte concentration (1 M KOH). The catalyst is made from non-precious metals and its fabrication is straight forward and directly applicable to large-scale synthesis.

First claim

What is claimed is:

1 . A nanostructured catalytic electrode, comprising:
(a) a nanoporous alloy material represented by the formula (Ni a Fe b )E t at %; (b) wherein a is in the range of 30<a<100; (c) wherein b is in the range of 0<b<60; (d) wherein t is in the range of 0<t<40; and (e) wherein E is an element selected from the group of elements consisting of Mg, Al, Ti, Mn, Zn, and Ta.

2 . The nanostructured electrode of claim 1 , wherein said nanoporous alloy material comprises Ni 60 Fe 30 Mn 10 .

3 . The nanostructured electrode of claim 1 , further comprising a layer of oxide that substantially covers one or more surfaces of the nanoporous alloy material.

4 . The nanostructured electrode of claim 3 , wherein said layer of oxide has a thickness in the range of 1 nm to 10 nm.

5 . The nanostructured electrode of claim 3 , wherein said layer of oxide is a substantially uniform thickness with a thickness in the range of 1 nm to 50 nm.

6 . The nanostructured electrode of claim 3 , wherein said layer of oxide is a NiFe oxide layer.

7 . The nanostructured electrode of claim 3 , wherein said layer of oxide is a NiFeE oxide layer, wherein E is an element selected from the group of elements consisting of Mg, Al, Ti, Mn, Zn, and Ta.

8 . The nanostructured electrode of claim 1 , wherein said alloy material has ligaments and pores on the order of 10 nm and has a Brunauer-Emmett-Teller (BET) surface area on the order of 43 m 2 /g.

9 . The nanostructured electrode of claim 3 , wherein said alloy material has a catalytic area per cm 2 on the order of 3×10 4 cm 2 .

10 . The nanostructured electrode of claim 3 , wherein said alloy material exhibits a catalytic activity towards water oxidation of 500 mA/cm 2 at 360 mV overpotential in 1 M KOH electrolyte.

11 . A method for fabricating a nanostructured oxygen-evolving catalytic electrode with a stable oxide coated network for alkaline electrolysis, comprising:
(a) providing a parent alloy of Ni, Fe and a sacrificial element; and (b) dealloying the parent alloy with exposure to a corroding medium; (c) wherein a portion of the sacrificial element is removed from the parent alloy to form a nanoporous structure; and (d) wherein a layer of oxide is formed on one or more surfaces of the nanoporous structure to provide a stable oxide coated nanostructured electrode.

12 . The method of claim 11 , wherein the parent alloy comprises an alloy material represented by the formula (Ni a Fe b )E t at %,
wherein a is in the range of 30<a<100; wherein b is in the range of 0<b<60; wherein t is in the range of 0<t<40; and wherein E is the sacrificial element selected from the group of elements consisting of Mg, Al, Ti, Mn, Zn, and Ta.

13 . The method of claim 12 , wherein said parent alloy has a composition index t of said formula (Ni a Fe b )E t at % that is greater than 50 at %, wherein E is an element selected from the group of elements consisting of Mg, Al, Ti, Mn, Zn, and Ta.

14 . The method of claim 11 , wherein said parent alloy has a composition of Ni 15 Fe 20 Mn 65 at %.

15 . The method of claim 11 , wherein said corroding medium is a solution selected from the group of solutions consisting of an ammonium sulfate solution; a potassium hydroxide solution; a sodium hydroxide solution; a hydrochloric acid solution; a sulfuric acid solution; and an acetic acid solution.

16 . The method of claim 11 , wherein the nanoporous alloy material produced by dealloying the parent alloy comprises:
an alloy represented by the formula (Ni a Fe b )E t at %; wherein a is in the range of 30<a<100; wherein b is in the range of 0<b<60; wherein E is an element selected from the group of elements consisting of Mg, Al, Ti, Mn, Zn, and Ta; and wherein t is in the range of 0<t<40.

17 . The method of claim 11 , wherein a ratio of index a to index b in the alloy material represented by the formula (Ni a Fe b )E t at % is 2:1;
wherein E is an element selected from the group of elements consisting of Mg, Al, Ti, Mn, Zn, and Ta.

18 . The method of claim 11 , wherein the nanoporous alloy material produced by dealloying the parent alloy comprises: Ni 60 Fe 30 Mn 10 .

19 . The method of claim 11 , wherein the layer of oxide is a NiFe oxide layer that has a thickness in the range of 1 nm to 50 nm.

20 . The method of claim 11 , wherein the layer of oxide is a NiFeE oxide layer that has a thickness in the range of 1 nm to 50 nm, wherein E is an element selected from the group of elements consisting of Mg, Al, Ti, Mn, Zn, and Ta.

21 . An electrochemical cell comprising:
(a) a vessel containing an aqueous alkali electrolyte and an ion permeable membrane separating the electrolyte into a first volume and a second volume; (b) a cathode coupled to a source of current disposed in the first volume of electrolyte; and (c) a nanostructured catalytic anode, wherein said anode comprises:
(i) an alloy material represented by the formula (Ni a Fe b )E t at %;
(ii) wherein a is in the range of 30<a<100;
(iii wherein b is in the range of 0<b<60;
(iv) wherein t is in the range of 0<t<40; and
(v) wherein E is an element selected from the group of elements consisting of Mg, Al, Ti, Mn, Zn, and Ta; and
(vi) a layer of oxide that substantially covers one or more surfaces of the alloy material.

22 . The cell of claim 21 , wherein a ratio of index a to index b in the alloy material represented by the formula (Ni a Fe b )E t at % is 2:1.

23 . The cell of claim 22 , wherein the alloy material comprises: Ni 60 Fe 30 Mn 10 .

24 . The cell of claim 21 , wherein the layer of oxide is a NiFe oxide layer that has a thickness in the range of 1 nm to 50 nm.

25 . The cell of claim 21 , wherein the layer of oxide is a NiFeE oxide layer that has a thickness in the range of 1 nm to 50 nm, wherein E is an element selected from the group of elements consisting of Mg, Al, Ti, Mn, Zn, and Ta.

26 . The cell of claim 21 , wherein said anode has ligaments and pores on the order of 10 nm and has a Brunauer-Emmett-Teller (BET) surface area on the order of 43 m 2 /g.

27 . The cell of claim 21 , wherein said anode has a catalytic area per cm 2 on the order of 3×10 4 cm 2 .

28 . The cell of claim 21 , wherein said anode exhibits a catalytic activity towards water oxidation of 500 mA/cm 2 at 360 mV overpotential in 1 M KOH electrolyte.

Assignees

• Univ California

Inventors

• Tolbert Sarah
• Detsi Eric
• Lesel Benjamin

Classifications

• C22C38/04

  containing manganese · CPC title

• H01M8/0232

  Metals or alloys · CPC title

• H01M2300/0014

  Alkaline electrolytes · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• C22C38/08

  containing nickel {(C22C38/105 takes precedence)} · CPC title