Gas sensor using metal oxide semiconducting nanofiber sensitized by alkali or alkaline earth metal and noble metal catalysts, and manufacturing method thereof

Patent metadata

Field	Value
Publication number	US-11673122-B2
Application number	US-202117321689-A
Country	US
Kind code	B2
Filing date	May 17, 2021
Priority date	Jul 27, 2020
Publication date	Jun 13, 2023
Grant date	Jun 13, 2023

Abstract

A member for a metal oxide nanofiber based gas sensor can include a metal nanoparticle catalyst and can be formed to be functionalized by binding the metal nanoparticle catalyst and an alkali or alkaline earth metal through electrospinning and heat treatment processes. The member can detect a trace amount of a gas with high selectivity and ultra-high sensitivity by uniformly binding the alkali or alkaline earth metal and the metal nanoparticle catalyst through electrospinning and high-temperature heat treatment.

First claim

What is claimed is:

1. A member for a gas sensor, the member comprising:
metal oxide nanofibers,
wherein the metal oxide nanofibers comprise a metal nanoparticle catalyst and an alkali or alkaline earth metal bound to be functionalized between metal oxide nanoparticles serving as a matrix, and
the metal oxide nanofibers are obtained by an electrospinning process followed by a heat treatment process.

2. The member of claim 1 , wherein a diameter of the metal oxide nanofibers is in a range of 50 nm to 10 μm, and a length of the metal oxide nanofibers is in a range of 1 μm to 100 μm.

3. The member of claim 1 , wherein the metal oxide nanoparticles are selected from the group consisting of WO 3 , ZnO, SnO 2 , TiO 2 , In 2 O 3 , Zn 2 SnO 4 , MnO 2 , which are n-type semiconductors, or is selected from the group consisting of CuO, Co 3 O 4 , Fe 2 O 3 , Fe 3 O 4 , PdO, LaCoO 3 , NiO, NiCo 2 O 4 , and Ag 2 O, which are p-type semiconductors.

4. The member of claim 1 , wherein the metal oxide nanofiber has an open pore structure in a size range of 50 nm to 100 μm between the metal oxide nanofibers which are networked and interconnected.

5. The member of claim 1 , wherein the metal nanoparticle catalyst is manufactured from an apoferritin protein template having a hollow structure with an inside diameter ranging from 7 nm to 8 nm.

6. The member of claim 5 , wherein the metal nanoparticle catalyst is synthesized by injecting a metal salt into the apoferritin protein template and performing reduction treatment through a reducing agent.

7. The member of claim 6 , wherein the metal salt contains one or more selected from the group consisting of Pt, Pd, Rh, Ru, Ni, Co, Cr, Ir, Au, Ag, Zn, Mn, Ga, Ge, W, Sn, Sr, In, Pb, Ta, Sb, Sc, and Ti.

8. The member of claim 1 , wherein a size of the metal nanoparticle catalyst is in a range of 1 nm to 5 nm.

9. The member of claim 1 , wherein the alkali or alkaline earth metal includes one or more selected from the group consisting of Na, K, Mg, Ca, Rb, Sr, Cs, and Ba.

10. The member of claim 1 , wherein the metal oxide nanofiber includes a second phase which is formed due to a reaction of the alkali or alkaline earth metal with the metal oxide nanofiber matrix through the heat treatment process.

11. The member of claim 1 , wherein the metal oxide nanofiber includes a plurality of heterointerfaces formed so that a second phase is formed due to reaction of the alkali or alkaline earth metal with the metal oxide nanofiber matrix and formed between the metal oxide nanofiber matrix, the second phase, and the metal nanoparticle catalyst.

12. The member of claim 11 , wherein the alkali or alkaline earth metal includes Na, and the metal oxide nanofiber matrix includes WO 3 .

13. A method of manufacturing metal oxide nanofibers, the method comprising:
synthesizing a nanoparticle catalyst inside an apoferritin protein template;
preparing a spinning solution by stirring the apoferritin template containing the nanoparticle catalyst and an alkali or alkaline earth metal salt with a metal oxide precursor/polymer composite solution;
electrospinning the spinning solution to synthesize metal oxide precursor/polymer composite nanofibers in which the nanoparticle catalyst and the alkali metal or alkaline earth metal salt are uniformly distributed; and
synthesizing one-dimensional porous metal oxide nanofibers by performing heat treatment on the synthesized composite nanofibers.

14. The method of claim 13 , wherein, in the synthesizing of the nanoparticle catalyst, a metal salt is injected into inner pores of the apoferritin protein template, and a reduction treatment is performed using a reducing agent to synthesize the metal nanoparticle catalyst.

15. The method of claim 13 , wherein, in the preparing of the spinning solution, a weight ratio of the polymer to the nanoparticle catalyst is in a range of 1:0.00001 to 1:0.1.

16. The method of claim 13 , wherein, in the preparing of the spinning solution, a weight ratio of the polymer to the alkali or alkaline earth metal salt is in a range of 1:0.00001 to 1:0.1.

17. The method of claim 13 , wherein, in the preparing of the spinning solution, stirring is performed at a temperature ranging from 20 degrees Celsius to 40 degrees Celsius for four to twenty-four hours.

18. The method of claim 13 , wherein, in the synthesizing of the metal oxide nanofibers, the nanoparticle catalyst and a second phase generated due to the alkali or alkaline earth metal salt are uniformly distributed and bound through the heat treatment.

19. The method of claim 13 , wherein, in the synthesizing of the metal oxide nanofibers, the heat treatment is performed at a temperature ranging from 500 degrees Celsius to 800 degrees Celsius.

20. The method of claim 13 , wherein, in the synthesizing of the metal oxide nanofibers, the apoferritin protein template and the polymer are thermally decomposed and removed through the heat treatment, and the metal oxide precursor is oxidized to form a one-dimensional metal oxide nanofiber structure.

Assignees

• Samsung Electronics Co Ltd
• Korea Advanced Inst Sci & Tech

Inventors

• Jung Won Jong
• Kim Il Doo
• Namkoong Kak
• Kim Dong Ha
• Lee Yeol Ho
• Lee Joon Hyung
• Chang Ki Young
• Jang Ji Soo
• Shin Ha Min
• Kim Yoon Hwa

Classifications

• G01N27/127 Primary

  comprising nanoparticles · CPC title

• B01J37/342

  of electric, magnetic or electromagnetic fields, e.g. for magnetic separation · CPC title

• G01N33/497

  of gaseous biological material, e.g. breath · CPC title

• D01D5/0015

  characterised by the initial state of the material · CPC title

• B01J23/6527

  Tungsten · CPC title