Metal carbide/carbon composite body having porous structure by three-dimensional connection of core-shell unit particles, preparation method thereof, and use of the composite body

Patent metadata

Field	Value
Publication number	US-9517452-B2
Application number	US-201514839320-A
Country	US
Kind code	B2
Filing date	Aug 28, 2015
Priority date	Oct 4, 2013
Publication date	Dec 13, 2016
Grant date	Dec 13, 2016

Abstract

The present invention relates to a metal carbide/carbon composite body having a porous structure, in which core-shell unit particles are three-dimensionally connected, a preparation method thereof, and the use of the composite body. More specifically, the present invention provides a metal carbide/carbon composite body, a preparation method thereof, and the use of the composite body, wherein the composite body is formed by high-temperature calcination of a metal oxalate hydrate body under a carbon monoxide-containing gas atmosphere, wherein the metal carbide/carbon composite body has a porous structure in which core-shell unit particles are three-dimensionally connected, wherein the core-shell unit particles comprise a metal carbide core formed by thermal decomposition of a metal oxalate hydrate; and a graphitic carbon shell, the product resulting from Boudouard reaction of carbon monoxide, formed on the metal carbide core.

First claim

The invention claimed is:

1. A metal carbide/carbon composite body which is formed by high-temperature calcination of a metal oxalate hydrate body having a certain shape under a carbon monoxide-containing gas atmosphere,
wherein the metal carbide/carbon composite body has a porous structure in which core-shell unit particles are three-dimensionally connected,
wherein the core-shell unit particles comprise a metal carbide core formed by thermal decomposition of a metal oxalate hydrate; and a graphitic carbon shell, the product resulting from Boudouard reaction of carbon monoxide, formed on the metal carbide core.

2. The metal carbide/carbon composite body of claim 1 , wherein the shape of the metal carbide/carbon composite body having a porous structure resembles the shape of a metal oxalate hydrate body.

3. The metal carbide/carbon composite body of claim 1 , wherein the average diameter of the metal carbide/carbon composite body having a porous structure is from 1 μm to 100 μm.

4. The metal carbide/carbon composite body of claim 1 , wherein the average diameter of the core-shell unit particles is from 1 nm to 100 nm.

5. The metal carbide/carbon composite body of claim 1 , wherein a core-shell unit particle serves as one microreactor.

6. The metal carbide/carbon composite body of claim 1 , wherein the metal oxalate hydrate body is an iron oxalate hydrate body, and a metal carbide formed therefrom is iron carbide.

7. A method for preparing the metal carbide/carbon composite body having a porous structure according to claim 1 ,
wherein the method comprises:
calcining a metal oxalate hydrate body having a certain shape at high temperature under a carbon monoxide-containing gas atmosphere (step 1 ).

8. The method of claim 7 , wherein the method comprises the following steps prior to step 1 :
preparing a mixture comprising a metal hydrate salt, a surfactant, a saccharide, and water (step 1 - 1 );
heating the mixture of step 1 - 1 to decompose the metal hydrate salt via hydrothermal reaction, thereby forming a metal oxalate hydrate body having a controlled shape (step 1 - 2 ); and
optionally cooling the product obtained in step 1 - 2 and washing the metal oxalate hydrate body (step 1 - 3 ).

9. The method of claim 8 , wherein the shape of the metal oxalate hydrate body is controlled by regulating the type of saccharide, the type of surfactant, the amount of saccharide added, and/or the amount of surfactant added.

10. The method of claim 9 , wherein the shape of the metal oxalate hydrate body is controlled to have the shape of a rectangular cuboid or a cube.

11. The method of claim 8 , wherein the hydrothermal reaction is carried out by heating the mixture of step 1 - 1 to a temperature of 80° C. to 150° C., followed by reacting the mixture for 30 minutes to 48 hours.

12. The method of claim 8 , wherein the metal hydrate salt is at least one selected from iron(III) chloride tetrahydrate, iron(II) chloride tetrahydrate, iron(III) chloride hexahydrate, iron(II) chloride tetrahydrate, iron(III) nitrate nonahydrate, iron(III) sulfate hydrate, iron(II) perchlorate hydrate, and iron(II) sulfate hydrate.

13. The method of claim 8 , wherein the saccharide is at least one selected from a monosaccharide, a disaccharide, and a polysaccharide.

14. The method of claim 13 , wherein the monosaccharide is at least one selected from glucose, fructose, and galactose, the disaccharide is at least one selected from sucrose, lactose, maltose, trehalose, melibiose, and cellobiose, and the polysaccharide is at least one selected from raffinose, stachyose, starch, dextrin, glycogen, and cellulose.

15. The method of claim 8 , wherein the surfactant is polyvinylpyrrolidone (PVP), a polymer surfactant, and the PVP having an average molecular weight of 10,000 to 36,000 is used.

16. The method of claim 7 , wherein the high-temperature calcination is carried out at a heat treatment temperature of 300° C. to 450° C.

17. The metal carbide/carbon composite body of claim 1 , wherein the metal carbide/carbon composite body is used as catalysts, adsorbents, electrode materials, or sensor materials.

18. A method for preparing liquid or solid hydrocarbons from syngas via the Fischer-Tropsch synthesis, wherein the method comprises:
applying the composite body of claim 1 as a catalyst in a Fischer-Tropsch synthesis reactor (step a); and
carrying out the Fischer-Tropsch synthesis in the presence of the catalyst by introducing syngas into the reactor (step b).

19. The method of claim 18 , wherein the composite body catalyst has a porous structure in which iron carbide/carbon unit particles in the shape of a core-shell are connected together, wherein the core-shell unit particles comprise an iron carbide core of a Hägg carbide (χ-Fe 5 C 2 ) species and a graphitic carbon shell.

Assignees

• Korea Energy Research Inst

Inventors

• Park Ji Chan
• Jung Heon
• Lee Ho Tae
• Yang Jung Il
• Chun Dong Hyun
• Hong Sung Jun
• Hong Seok Yong

Classifications

• B01J35/45

  Nanoparticles · CPC title

• B01J35/0013

  Operations & Transport · mapped topic

• B01J37/082

  Decomposition and pyrolysis · CPC title

• B01J37/10

  in the presence of water, e.g. steam · CPC title

• B01J37/08

  Heat treatment {(B01J37/0009, B01J37/0018 take precedence)} · CPC title