Mixed-conductor enhanced composite and core-shell oxides for cyclic redox production of fuels and chemicals

Patent metadata

Field	Value
Publication number	US-10486143-B2
Application number	US-201515109894-A
Country	US
Kind code	B2
Filing date	Jan 6, 2015
Priority date	Jan 6, 2014
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

Compositions and methods for preparing and using ceramic mixed ionic-electronic conductor (MIEC) enhanced transition metals and metal oxides in composite or core-shell forms are disclosed. The presently disclosed compositions are stable at high temperatures and can carry as much as about 20 weight % oxygen.

First claim

That which is claimed:

1. A core-shell redox catalyst comprising:
(i) metal oxide core, wherein the metal oxide core comprises at least one transition metal oxide and mixtures thereof, wherein the at least one transition metal oxide is an oxide of a transition metal selected from the group consisting of Mn, Fe, Co, Ni, V, Mo, Cu, Zn and mixtures thereof, a spinel oxide having a formula A 2+ B 2 3+ O 4 2− , wherein A and B are each independently a metal cation, or combinations thereof:
(ii) A rigid mixed ionic-electronic conductive (MIEC) shell substantially enclosing the metal oxide core, wherein the rigid MIEC shell comprises a perovskite structure; and
(iii) A plurality of surface catalytic sites.

2. The core-shell redox catalyst of claim 1 , wherein the metal cation is selected from the group consisting of magnesium, zinc, iron, manganese, aluminum, chromium, titanium, and silicon.

3. The core-shell redox catalyst of claim 1 , wherein the rigid MIEC shell is selected from the group consisting of La x Sr 1-x FeO 3 , BaCe y Fe 1-y O 3 , and CaTi z Fe 1-z O 3 , wherein 0.2<x<0.8, 0.2<y<0.8, and 0.05<z<0.75.

4. The core-shell redox catalyst of claim 1 , further comprising an active metal.

5. The core-shell redox catalyst of claim 1 , wherein the core-shell redox catalyst has a lattice oxygen capacity of about 5 w.t. % to about 20 w.t. %.

6. The core-shell redox catalyst of claim 1 , wherein the rigid MIEC shell is selected from the group consisting of BaCe y Fe 1-y O 3 and CaTi z Fe 1-z O 3 , wherein 0.2<y<0.8, and 0.05<z<0.75.

7. The core-shell redox catalyst of claim 1 , wherein the metal oxide core comprises an iron oxide;
wherein the rigid MIEC shell comprises La x Sr 1-x FeO 3 , wherein 0.2<x<0.8;
wherein a ratio of the metal oxide of the core to the MIEC shell is about 4:1 to about 1:4;
wherein the core-shell redox catalyst has a lattice oxygen capacity of about 10 w.t. % to about 20 w.t. %; and
wherein a surface area of the core-shell redox catalyst is about 15 m 2 g −1 or less.

8. A method for generating syngas, the method comprising contacting methane, light hydrocarbons, or a mixture thereof with a redox catalyst according to claim 1 , thereby reducing the redox catalyst to produce a reduced redox catalyst and converting the methane and/or light hydrocarbons into syngas.

9. The method of claim 8 , further comprising contacting the reduced redox catalyst with H 2 O/O 2 to regenerate the redox catalyst and to produce H 2 and/or heat.

Assignees

• Univ North Carolina State

Inventors

• Li Fanxing
• Chen Yanguang

Classifications

• B01J23/78

  with alkali- or alkaline earth metals · CPC title

• B01J23/005

  Spinels · CPC title

• B01J38/48

  Liquid treating or treating in liquid phase, e.g. dissolved or suspended · CPC title

• C01B3/40

  characterised by the catalyst · CPC title

• C01B2203/0261

  containing a catalytic partial oxidation step [CPO] · CPC title