Materials for ammonia synthesis

Patent metadata

Field	Value
Publication number	US-2020224323-A1
Application number	US-202016742390-A
Country	US
Kind code	A1
Filing date	Jan 14, 2020
Priority date	Jan 14, 2019
Publication date	Jul 16, 2020
Grant date	—

Abstract

Disclosed herein are doped perovskite oxides. The doped perovskite oxides may be used as a cathode material in an electrochemical cell to electrochemically generate ammonia from N 2 . The doped perovskite oxides may be combined with nitride compounds, for instance iron nitride, to further increase the efficiency of the ammonia production.

First claim

What is claimed is:

1 . A perovskite oxide having the formula:
A 1 w A 2 x X y Fe z O 3 , wherein: A 1 is selected from La, Tb, Gd, Sm, Pr, and Nd; A 2 is selected from Sr, Mg, Ca, and Ba; X is one or more metals in the +1 or +2 oxidation state; w is from 0.5-1.0; x is from 0-0.5; y is from 0-0.5; and z is from 0.5 to less than 1.0; wherein w, x, y, and z are chosen to maintain electroneutrality.

2 . The perovskite oxide of claim 1 , wherein X is Ni, Co, Ti, Mn, Zn, Cu, Li, Al, Sc, V, Cr, Ga, Ge, Y, Zr, Nb, In, V, W, Mb, Pd, Pt, Ag, Au, Cd, or a combination thereof.

3 . The perovskite oxide of claim 1 , wherein A 1 is La.

4 . The perovskite oxide of claim 3 , wherein A 2 is Sr.

5 . The perovskite oxide of claim 1 , wherein w is from 0.6 to 0.9.

6 . The perovskite oxide of claim 5 , wherein z is from 0.6 to 0.9.

7 . The perovskite oxide of claim 4 , wherein X is Ni or Co.

8 . The perovskite oxide of claim 1 , wherein x is from 0.15 to 0.25.

9 . The perovskite oxide of claim 1 , wherein y is from 0.15 to 0.25.

10 . A cathode comprising the perovskite oxide of claim 1 .

11 . The cathode of claim 10 , further comprising one or more nitride compounds having the formula M a N b , wherein M is selected from Fe, Mb, Co, Cr, and V, a is selected from 1, 2, 3, or and 4, and b is selected from 1, 2, 3, and 4

12 . The cathode of claim 11 , wherein M is Fe.

13 . The cathode of claim 11 , wherein the weight ratio of perovskite oxide to nitride compound is from 10:1 to 1:10.

14 . A solid oxide electrolyte cell comprising:
(a) the cathode of claim 11 ; (b) an anode; and (c) an electrolyte disposed between the cathode and anode;
wherein the cathode and anode are in electrical communication with a power supply configured to provide a voltage potential between the cathode and anode.

15 . The cell of claim 14 , wherein the electrolyte is an oxygen-ion conducting solid electrolyte.

16 . The cell of claim 14 , wherein the electrolyte comprises yttria stabilized zirconia (YSZ), scandia stabilized zirconia (ScSZ), gadolinium doped ceria (GDC), perovskite-type oxides such as lanthanum strontium gallium magnesium oxide (LSGM), lanthanum yttrium germanate (LaYGe), or a combination thereof.

17 . The cell of claim 14 , wherein the anode comprises a combination of a lanthanum strontium manganate-type perovskite and at least one doped fluorite oxide, for instance yttria stabilized zirconia, GDC, and ABO 3 -type perovskite oxides where A is selected from alkaline earth metals and lanthanoids and B is one or more transition metals.

18 . The cell of claim 14 , wherein the anode comprises palladium, platinum, silver, gold, yttria stabilized zirconia, lanthanum strontium manganate, or a combination thereof.

19 . A method of generating ammonia, comprising:
(c) electrochemically reducing H 2 O and N 2 with the perovskite oxide of claim 1 , to provide NH 3 and O 2 − ; and (d) oxidizing the O 2 − to give oxygen gas.

20 . The method of claim 19 , wherein the electrochemical reduction is performed by supplying an electric current to the perovskite oxide of claim 1 , wherein the current applied is in an amount from 0.1-50 mA.

Assignees

• Ohio State Innovation Foundation

Inventors

• Ozkan Umit
• Gunduz Seval
• Deka Dhruba Jyoti

Classifications

• Y02E60/50

  Fuel cells · CPC title

• C25B13/07

  based on ceramics · CPC title

• C25B1/27

  Ammonia · CPC title

• C25B9/19 Primary

  with diaphragms · CPC title

• C25B9/23

  comprising ion-exchange membranes in or on which electrode material is embedded · CPC title