Hierarchically structured, nitrogen-doped carbon membranes

Patent metadata

Field	Value
Publication number	US-10323329-B2
Application number	US-201715767488-A
Country	US
Kind code	B2
Filing date	Jan 24, 2017
Priority date	Jan 25, 2016
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

The present invention is a structure, method of making and method of use for a novel macroscopic hierarchically structured, nitrogen-doped, nano-porous carbon membrane (HNDCMs) with asymmetric and hierarchical pore architecture that can be produced on a large-scale approach. The unique HNDCM holds great promise as components in separation and advanced carbon devices because they could offer unconventional fluidic transport phenomena on the nanoscale. Overall, the invention set forth herein covers a hierarchically structured, nitrogen-doped carbon membranes and methods of making and using such a membranes.

First claim

What is claimed is:

1. A method of making a hierarchically structured, nitrogen-doped carbon membrane, the method comprising the steps of:
(a) pouring onto a substrate a polymer solution comprising poly[1-cyanomethyl-3-vinylimidazolium bis(trifluoromethanesulfonyl) imide] (PCMVImTf 2 N) and poly(acrylic acid) (PAA) in a dimethyl formamide solution to form a sheet;
(b) drying the sheet to form a gradient porous polymer membrane;
(c) contacting the gradient porous polymer membrane with an ammonium hydroxide aqueous solution; and
(d) pyrolyzing the gradient porous polymer membrane of step (c) in the presence of nitrogen to form the hierarchically structured, nitrogen-doped carbon membrane.

2. The method of claim 1 , wherein the drying step is performed at a temperature of 80° C. to 120° C.

3. The method of claim 1 , wherein the drying step is performed for 1 to 20 hours.

4. The method of claim 1 , wherein the molecular weight of the PAA is from 2,000 g/mol to 3,000,000 g/mol.

5. The method of claim 1 , wherein the molecular weight of PCMVImTf 2 N is from 22,000 g/mol to 100,000 g/mol.

6. The method of claim 1 , further comprising contacting the gradient porous polymer membrane with a metallic salt aqueous solution comprising Co, Fe, Ni, Cr or Ge.

7. The method of claim 1 , wherein the contacting step comprises soaking the gradient porous polymer membrane in the ammonium hydroxide for one to 36 hours.

8. The method of claim 1 , wherein pyrolysis step is performed at a temperature of 500° C. to 1500° C.

9. The method of any of claim 1 further comprising:
refluxing the gradient porous polymer membrane in an aqueous cobalt acetate solution for about 12 to about 36 hours; rinsing; and drying the refluxed gradient porous polymer membrane prior to the pyrolysis step; and
phosphatizing the Co-containing membrane in the presence of monosodium phosphate (NaH 2 PO 4 ) and nitrogen at a temperature of about 175° C. to about 525° C. to form a functionalized nanoporous carbon membrane comprising Co/CoP Janus-type nanocrystals after the pyrolysis step.

10. A nanoporous carbon membrane comprising:
a nitrogen-doped gradient porous polymer membrane with a hierarchical pore architecture,
wherein the polymer comprises poly[1-cyanomethyl-3-vinylimidazolium bis(trifluoromethanesulfonyl) imide] (PCMVImTf2N) and poly(acrylic acid) (PAA) and
wherein the pores are interconnected and gradually decrease in size from a first surface of the membrane to a second surface of the membrane.

11. The nanoporous carbon membrane of claim 10 , further comprising a metal catalyst selected from the group consisting of Co, Fe, Ni, Cr, Ge.

12. The nanoporous carbon membrane of claim 10 , wherein the membrane is functionalized with Co/CoP Janus nanocrystals.

13. A method of producing hydrogen comprising electrochemical splitting of water using a nanoporous carbon membrane comprising:
(a) nitrogen-doped gradient porous polymer membrane with a hierarchical pore architecture,
wherein the polymer comprises poly[1-cyanomethyl-3-vinylimidazolium bis(trifluoromethanesulfonyl) imide] (PCMVImTf 2 N) and poly(acrylic acid) (PAA) and
wherein the pores are interconnected and gradually decrease in size from a first surface of the membrane to a second surface of the membrane; and

(b) a single metal catalyst.

14. The method of claim 13 , wherein the metal catalyst is cobalt.

15. The method of claim 13 , wherein the electrochemical splitting of water occurs under alkaline conditions.

16. The method of claim 13 , wherein the electrochemical splitting of water occurs under acidic conditions.

17. The method of claim 16 , where in the membrane is functionalized with Co/CoP Janus nanocrystals.

18. The method of claim 1 , any of claim 13 , wherein electrochemical splitting of water comprises a hydrogen evolution reaction (HER).

19. The method of claim 18 , wherein the electrochemical splitting of water further comprises an oxygen evolution reaction.

20. The method of claim 13 , wherein the electrochemical splitting comprises:
(a) a hy1drogen evolution reaction; and
(b) an oxygen evolution reaction.

Assignees

• Univ King Abdullah Sci & Tech

Inventors

• Wang Hong
• Wu Tao

Classifications

• B01D2325/34

  Molecular weight or degree of polymerisation · CPC title

• B01J35/065

  Operations & Transport · mapped topic

• B01D2325/10

  Catalysts being present on the surface of the membrane or in the pores · CPC title

• C08L33/02

  Homopolymers or copolymers of acids; Metal or ammonium salts thereof · CPC title

• B01D2323/18

  Pore-control agents or pore formers · CPC title