Ultra-sensitive gas sensors based on tellurium-single walled carbon nanotube hybrid nanostructures

Patent metadata

Field	Value
Publication number	US-9632057-B2
Application number	US-201314050932-A
Country	US
Kind code	B2
Filing date	Oct 10, 2013
Priority date	Oct 10, 2012
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

A gas sensor operable at ambient conditions, the sensor includes functionalized feather-like tellurium (Te) nanostructures on single-walled carbon nanotube (SWNTs) networks.

First claim

What is claimed is:

1. A gas sensor operable at ambient conditions, the sensor comprising:
feather-like tellurium (Te) nanostructures functionalized on single-walled carbon nanotube (SWNTs) networks; and
tailoring a morphology and a density of the feather-like Te nanostructures to a response and a recovery time of approximately 36 sec and 7 min to 100 ppb v NO 2 gas at room temperature, respectively.

2. The sensor of claim 1 , comprising:
a silicon wafer substrate configured to receive the functionalized feather-like tellurium (Te) nanostructures on the single-walled carbon nanotube (SWNTs) networks.

3. The sensor of claim 2 , comprising:
a plurality of working electrodes on the silicon wafer substrate; and
a sensing cell having a gas inlet and a gas outlet.

4. A method of fabricating a gas sensor, the method comprising:
electrodepositing a tellurium (Te) solution on aligned single-walled carbon nanotubes (SWNTs); and
controlling deposition charge density during the electrodeposition of the tellurium (Te) solution on the aligned single-walled carbon nanotubes (SWNTs) to form feather-like tellurium (Te) nanostructures.

5. The method of claim 4 , comprising:
preparing a carbon nanotube suspension of carboxylated single-walled carbon nanotubes in a solution of N, N-dimethylformamide;
sonicating the solution until a uniform suspension is obtained;
centrifuging the suspension and collecting a supernatant;
placing the supernatant into a Teflon cell with a chip for SWNT alignment; and
obtaining alignment of the single-walled carbon nanotubes (SWNTs) across the microelectrodes.

6. The method of claim 5 , comprising:
obtaining alignment by applying 2 peak to peak voltage (V pp ) and 4 MHz frequency for approximately 4 seconds.

7. The method of claim 6 , comprising:
rinsing the synthesized sensor with nanopure water;
drying the sensor with ultra-pure N 2 gas; and
annealing the sensor.

8. The method of claim 7 , wherein the annealing is at 300° C. for 2 hours in forming gas.

9. The method of claim 4 , wherein the electrodeposition of the tellurium (Te) solution comprises:
electrodepositing Te from an acidic nitric bath containing HTeO 2 + .

10. The method of claim 5 , comprising:
rinsing the sensor with nanopure water; and
drying the sensor with nitrogen gas.

11. The method of claim 5 , comprising:
configuring the sensor to sense nitrogen dioxide (NO 2 ).

12. The method of claim 11 , comprising:
tailoring the morphology and density of the feather-like Te nanostructures to a response and a recovery time of approximately 36 sec and 7 min to 100 ppb v NO 2 gas at room temperature, respectively.

13. The method of claim 4 , comprising:
forming the feather-like tellurium (Te) nanostructures at a charge density of about 94.5 mC/cm 2 to about 189 mC/cm 2 .

14. The method of claim 9 , wherein the acidic nitric bath containing HTeO 2 + comprises:
10 mM (millimolar) of HTeO 2 + .

15. The method of claim 9 , comprising:
fixing an applied potential during electrodeposition at −0.75 V to −1.28 V.

Assignees

• Univ California

Inventors

• Myung Nosang V
• Zhang Miluo

Classifications

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• C25D5/54 Primary

  Electroplating of non-metallic surfaces (C25D7/12 takes precedence) · CPC title

• C25D5/50

  by heat-treatment · CPC title

• C25D9/00

  Electrolytic coating other than with metals (C25D11/00, C25D15/00 take precedence; electrophoretic coating C25D13/00) · CPC title

• C25D3/02

  from solutions (C25D5/34 - C25D5/46 take precedence) · CPC title