Nanofibrous electrocatalyst including nanofibrous continuous network of graphitic nanofibers having embedded catalytically active metal moieties

Patent metadata

Field	Value
Publication number	US-10700361-B2
Application number	US-201615144650-A
Country	US
Kind code	B2
Filing date	May 2, 2016
Priority date	Sep 28, 2012
Publication date	Jun 30, 2020
Grant date	Jun 30, 2020

Abstract

A nanofibrous catalyst and method of manufacture. A precursor solution of a transition metal based material is formed into a plurality of interconnected nanofibers by electro-spinning the precursor solution with the nanofibers converted to a catalytically active material by a heat treatment. Selected subsequent treatments can enhance catalytic activity.

First claim

What is claimed is:

1. An article of manufacture of a catalyst, comprising:
a nanofibrous continuous network of graphitic nanofibers having catalytically active metal moieties embedded within the graphitic nanofibers and the graphitic nanofibers having a matrix of interconnected nanopores exposing the catalytically active metal moieties,
wherein a graphitic skin of the graphitic nanofibers provides a protective layer over the catalytically active metal moieties embedded within the graphitic nanofibers.

2. The article of manufacture as defined in claim 1 , wherein the catalyst forms a component selected from the group of a cathode in PEMFC membrane electrode assembly and a cathode of a lithium air battery.

3. The article of manufacture as defined in claim 1 ,
wherein the metal moieties originate from a precursor having composition comprising transition metal zeolitic imidazolate frameworks comprising iron zeolitic imidazole framework (Fe-Im), cobalt zeolitic imidazole framework (Co-Im), iron zeolitic methyl-imidazole framework (Fe-mIm), cobalt zeolitic methyl-imidazole framework (Co-mlm), zinc zeolitic imidazole framework (Zn-Im), zinc zeolitic methyl-imidazole framework (Zn-mlm), or zinc zeolitic ethyl-imidazole framework (Zn-elm).

4. The article of manufacture of claim 1 , wherein the catalytically active metal moieties comprise catalytically active transition metal, nitrogen and carbon moieties.

5. The article of manufacture of claim 1 , wherein the catalytically active metal moieties comprise catalytically active metal oxide compound crystallites.

6. The article of manufacture as defined in claim 1 , wherein the graphitic nanofibers have a diameter of about ten nanometers to one thousand nanometers.

7. The article of manufacture of claim 1 , wherein the graphitic nanofibers comprise a thermally carbonized backbone forming polymer and a carbonized pore forming polymer.

8. The article of manufacture of claim 7 , wherein the backbone forming polymer is carbonized to graphitic form.

9. The article of manufacture of claim 8 , wherein the graphitic nanofibers have crosslinking therebetween.

10. A cathode comprising:
a carbon paper substrate; and
a dried catalyst ink comprising a plurality of graphitic nanofibers having catalytically active metal moieties embedded within the graphitic nanofibers and the graphitic nanofibers having a matrix of interconnected nanopores throughout exposing the catalytically active metal moieties,
wherein the dried catalyst ink is disposed on the carbon paper substrate,
wherein a graphitic skin of the graphitic nanofibers provides a protective layer over the catalytically active metal moieties embedded within the graphitic nanofibers.

11. The cathode of claim 10 , wherein the catalytically active metal moieties comprise catalytically active transition metal, nitrogen and carbon moieties.

12. The cathode of claim 10 , wherein the catalytically active metal moieties comprise catalytically active metal oxide compound crystallites.

13. The cathode of claim 10 , wherein the graphitic nanofibers comprise a thermally carbonized backbone forming polymer and a carbonized pore forming polymer.

14. The cathode of claim 10 , wherein the graphitic nanofibers have crosslinking therebetween.

15. A fuel cell membrane electrode assembly comprising:
an anode;
a cathode comprising:
a carbon paper substrate; and
a dried catalyst ink comprising a catalytic powder having a plurality of graphitic nanofibers and catalytically active metal moieties embedded within the graphitic nanofibers and the graphitic nanofibers having a matrix of interconnected nanopores exposing the catalytically active metal moieties, and

a fuel cell membrane having the anode and cathode pressed into the fuel cell membrane,
wherein a graphitic skin of the graphitic nanofibers provides a protective layer over the catalytically active metal moieties embedded within the graphitic nanofibers.

16. The fuel cell membrane electrode assembly of claim 15 , wherein the catalyst ink has a dry catalyst loading of 1.8 mg/cm 2 on the carbon paper substrate.

17. The fuel cell membrane electrode assembly of claim 15 , wherein the catalytically active metal moieties comprise catalytically active transition metal, nitrogen and carbon.

18. The fuel cell membrane electrode assembly of claim 15 , wherein the catalytically active metal compound crystallites comprise catalytically active metal oxide compound crystallites.

19. The fuel cell membrane electrode assembly of claim 15 , wherein the graphitic nanofibers comprise a thermally carbonized backbone forming polymer and a carbonized pore forming polymer.

Assignees

• Uchicago Argonne Llc

Inventors

• Liu Di-Jia
• Shui Jianglan
• Chen Chen

Classifications

• H01M50/437

  Glass · CPC title

• Y02P70/50

  Manufacturing or production processes characterised by the final manufactured product · CPC title

• H01M50/44

  Fibrous material · CPC title

• Y02E60/50

  Fuel cells · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title