3d reduced graphene oxide foams embedded with nanocatalysts, synthesizing methods and applications of same

Patent metadata

Field	Value
Publication number	US-2019048482-A1
Application number	US-201816058587-A
Country	US
Kind code	A1
Filing date	Aug 8, 2018
Priority date	Aug 10, 2017
Publication date	Feb 14, 2019
Grant date	—

Abstract

A method of synthesizing three-dimensional (3D) reduced graphene oxide (RGO) foams embedded with water splitting nanocatalysts includes providing a first solution containing nickel (II) nitrate, a second solution containing iron (III) nitrate, and a graphene oxide (GO) aqueous suspension; mixing the GO aqueous suspension with the first solution and the second solution to form a GO-Ni—Fe mixture; adjusting a pH value of the GO-Ni—Fe mixture to be about 3.5; and performing hydrothermal reaction in the GO-Ni—Fe mixture to form RGO-Ni—Fe foams, wherein nanocatalysts containing Ni-Fi oxide particles are embedded in porous structures of the 3D RGO foams.

First claim

What is claimed is:

1 . A method of synthesizing a three-dimensional (3D) reduced graphene oxide (RGO) foam embedded with nanocatalysts, comprising:
providing a first solution containing nickel (II) nitrate, a second solution containing iron (III) nitrate, and a graphene oxide (GO) aqueous suspension; mixing the GO aqueous suspension with the first solution and the second solution to form a GO-Ni—Fe mixture; adjusting a pH value of the GO-Ni—Fe mixture to be about 3.5; and performing hydrothermal reaction in the GO-Ni—Fe mixture to form a RGO-Ni—Fe foam, wherein nanocatalysts containing Ni-Fi oxide particles are embedded in a porous structure of the 3D RGO foam.

2 . The method of claim 1 , wherein the GO-Ni—Fe mixture is characterized with pH=3.5 and C:Ni:Fe=14:1:0.33.

3 . The method of claim 1 , wherein the first and second solutions are provided by dissolving Ni(NO 3 ) 2 .6H 2 O and Fe(NO 3 ) 3 .9H 2 O into deionized water, respectfully.

4 . The method of claim 1 , wherein the pH value of the GO-Ni—Fe mixture is adjusted by adding a NaOH solution therein.

5 . The method of claim 1 , wherein the hydrothermal reaction in the GO-Ni—Fe mixture is performed in a sealed autoclave for hydrothermal reaction at a predetermined temperature for a period of time.

6 . The method of claim 5 , wherein the predetermined temperature is in a ranges of about 160-200° C., and the period of time is in a range of about 7-11 h.

7 . The method of claim 1 , further comprising washing the RGO-Ni—Fe foam with deionized water.

8 . The method of claim 7 , further comprising freeze-drying the RGO-Ni—Fe foam under about 0.05 mbar vacuum at about −50° C. to obtain the RGO-Ni—Fe solid foam.

9 . The method of claim 1 , further comprising, prior to performing hydrothermal reaction in the GO-Ni—Fe mixture, ultrasonicateing the GO-Ni—Fe mixture to remove air bubbles that are trapped in the GO-Ni—Fe mixture.

10 . A 3D RGO foam embedded with nanocatalysts, synthesized according to the method of claim 1 .

11 . A device for water splitting, comprising a working electrode containing 3D RGO foams embedded with nanocatalysts, synthesized according to the method of claim 1 .

12 . A method of synthesizing a three-dimensional (3D) reduced graphene oxide (RGO) foam embedded with nanocatalysts, comprising:
providing at least one solution containing at least one precursor of nanocatalysts, and a graphene oxide (GO) aqueous suspension; mixing the GO aqueous suspension with the at least one solution to form a mixture; and performing hydrothermal reaction in the mixture to form a 3D RGO foam embedded with the nanocatalysts.

13 . The method of claim 12 , wherein the at least one precursor comprises Na 2 MoO 4 and L-cysteine.

14 . The method of claim 13 , wherein the mixture is characterized with pH=5.8.

15 . The method of claim 13 , wherein the 3D RGO foam embedded with the nanocatalysts is a 3D RGO-MoS 2 foam.

16 . The method of claim 12 , wherein the at least one solution comprises a first solution containing nickel (II) nitrate, and a second solution containing iron (III) nitrate.

17 . The method of claim 16 , wherein the first and second solutions are formed by dissolving Ni(NO 3 ) 2 .6H 2 O and Fe(NO 3 ) 3 .9H 2 O into deionized water, respectfully.

18 . The method of claim 16 , wherein the mixture is characterized with pH=3.5 and C:Ni:Fe=14:1:0.33.

19 . The method of claim 16 , wherein the hydrothermal reaction in the mixture is performed in a sealed autoclave for hydrothermal reaction at a predetermined temperature for a period of time.

20 . The method of claim 19 , wherein the predetermined temperature is in a ranges of about 160-200° C., and the period of time is in a range of about 7-11 h.

21 . The method of claim 16 , wherein the 3D RGO foam embedded with the nanocatalysts is the RGO-Ni—Fe foam.

22 . The method of claim 21 , further comprising freeze-drying the RGO-Ni—Fe foam under about 0.05 mbar vacuum at about −50° C.

23 . The method of claim 12 , further comprising, prior to performing hydrothermal reaction in the mixture, ultrasonicateing the mixture to remove air bubbles that are trapped in the mixture.

24 . A 3D RGO foam embedded with nanocatalysts, synthesized according to the method of claim 12 .

25 . A device for water splitting, comprising a working electrode containing 3D RGO foams embedded with nanocatalysts, synthesized according to the method of claim 12 .

Assignees

• Univ Arkansas

Inventors

• Zhao Wei
• Wang Daoyuan

Classifications

• B01J23/745

  Iron · CPC title

• B01J27/20

  Carbon compounds · CPC title

• B01J23/755

  Nickel · CPC title

• B01J23/883

  and nickel · CPC title

• B01J37/00

  Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts · CPC title