Multifunctional potentiometric gas sensor array with an integrated temperature control and temperature sensors

Patent metadata

Field	Value
Publication number	US-9027387-B2
Application number	US-68236508-A
Country	US
Kind code	B2
Filing date	Oct 9, 2008
Priority date	Oct 9, 2007
Publication date	May 12, 2015
Grant date	May 12, 2015

Abstract

Embodiments of the subject invention relate to a gas sensor and method for sensing one or more gases. An embodiment incorporates an array of sensing electrodes maintained at similar or different temperatures, such that the sensitivity and species selectivity of the device can be fine tuned between different pairs of sensing electrodes. A specific embodiment pertains to a gas sensor array for monitoring combustion exhausts and/or chemical reaction byproducts. An embodiment of the subject device related to this invention operates at high temperatures and can withstand harsh chemical environments. Embodiments of the device are made on a single substrate. The devices can also be made on individual substrates and monitored individually as if they were part of an array on a single substrate. The device can incorporate sensing electrodes in the same environment, which allows the electrodes to be coplanar and, thus, keep manufacturing costs low. Embodiments of the device can provide improvements to sensitivity, selectivity, and signal interference via surface temperature control.

First claim

The invention claimed is:

1. A gas sensor, comprising:
a substrate, wherein the substrate comprises an electrolyte;
a reference electrode;
at least two sensing electrodes, wherein the at least two sensing electrodes are positioned on the substrate, wherein the at least two sensing electrodes are in contact with the electrolyte;
a temperature control mechanism, wherein the temperature control mechanism is configured to alter a corresponding one or more temperatures of one or more of the at least two sensing electrodes such that the at least two sensing electrodes are at a corresponding at least two operating temperatures; and
an EMF detector, wherein the EMF detector is configured to measure a corresponding at least two EMFs between the at least two sensing electrodes and the reference to produce a corresponding at least two measured EMFs,
wherein the gas sensor is configured such that, when the at least two sensing electrodes are at the corresponding at least two operating temperatures, the reference electrode is at a reference electrode temperature, and the at least two sensing electrodes are exposed to an environment of interest, the at least two measured EMFs provide information with respect to one or more gases in the environment of interest.

2. The gas sensor according to claim 1 , wherein the at least two sensing electrodes are disposed on a surface of the substrate.

3. The gas sensor according to claim 1 , wherein a first measured EMF of the at least two measured EMFs between a first sensing electrode of the at least two sensing electrodes and the reference electrode indicates whether a first gas is present in the environment of interest.

4. The gas sensor according to claim 1 , wherein a first measured EMF of the at least two measured EMFs between a first sensing electrode of the at least two sensing electrodes and the reference electrode indicates a concentration of a first gas present in the environment of interest.

5. The gas sensor according to claim 1 , wherein the reference electrode is in contact with the electrolyte.

6. The gas sensor according to claim 5 , wherein the reference electrode is exposed to the environment of interest, wherein the EMF detector is configured to measure an additional EMF between a first sensing electrode of the at least two sensing electrodes and a second sensing electrode of the at least two sensing electrodes to produce an additional measured EMF, wherein the gas sensor is configured such that, when the at least two sensing electrodes are at the corresponding at least two operating temperatures, the reference electrode is at a reference electrode temperature, and the at least two sensing electrodes are exposed to an environment of interest, the at least two measured EMFs and the additional measured EMF provide information with respect to one or more gases in the environment of interest.

7. The gas sensor according to claim 6 , wherein upon exposure to a gas to be measured, a corresponding EMF occurs between a selected two sensing electrodes of the at least two sensing electrodes.

8. The gas sensor according to claim 6 , wherein the first sensing electrode and the second sensing electrode are formed of the same material and are maintained at different temperatures by a corresponding first heating element and a corresponding second heating element.

9. The gas sensor according to claim 8 , wherein the at least two sensing electrodes are all formed of the same material and are all maintained at different temperatures.

10. The gas sensor according to claim 8 , wherein each of the at least one of the at least two sensing electrodes are formed of the same material, are maintained at the same temperature, and have different microstructures, sizes, or thicknesses than each of the other of the at least one of the at least two sensing electrodes of the same material.

11. The gas sensor according to claim 10 , wherein the EMF detector is configured to measure a corresponding EMF of any two of the at least two sensing electrodes and the reference electrode maintained at a different temperature, having a different microstructure, having a different size, or having a different thickness.

12. The gas sensor according to claim 6 , wherein the at least two sensing electrodes and the reference electrode comprise one or more electrodes of a first material and one or more electrodes of a second material, wherein each of the electrodes of the at least two sensing electrodes and reference electrode is maintained at one of two or more different temperatures by two or more heating elements.

13. The gas sensor according to claim 12 , wherein the EMF detector is configured to measure a corresponding EMF of any two electrodes of the at least two sensing electrodes and reference electrode formed of a different material or maintained at a different temperature.

14. The gas sensor according to claim 12 , wherein each of the at least one of the at least two sensing electrodes and reference electrode formed of a same material are maintained at a first of the two or more temperatures and have different microstructures, sizes, or thicknesses than each of the other of the at least one of the at least two sensing electrodes of the same material.

15. The gas sensor according to claim 14 , wherein any two electrodes of the at least two sensing electrodes and reference electrode are formed of a different material, maintained at a different temperature, have a different microstructure, have a different size, or have a different thickness.

16. The gas sensor according to claim 12 , wherein the heating elements comprises resistor elements.

17. The gas sensor according to claim 16 , wherein the resistor elements are formed of platinum.

18. The gas sensor according to claim 16 , wherein each resistor element is disposed in a pattern on an opposite surface of the electrolyte to one of the sensing electrodes of the at least two sensing electrodes and reference electrode.

19. The gas sensor according to claim 16 , wherein a pattern of each resistor element comprises a C-shape pattern, a spiral pattern, or a serpentine pattern.

20. The gas sensor according to claim 6 , wherein electrodes of the at least two sensing electrodes and reference electrode comprise metal or a semiconducting oxide.

21. The gas sensor according to claim 6 , wherein electrodes of the at least two sensing electrodes and reference electrode comprise at least one platinum electrode.

22. The gas sensor according to claim 6 , wherein electrodes of the at least two sensing electrodes and reference electrode comprise at least one La 2 CuO 4 (LCO) electrode.

23. The gas sensor according to claim 6 , wherein the first sensing electrode and the second sensing electrode provide the additional measured EMF providing information with respect to a first of the one or more gases and a third sensing electrode and a fourth sensing electrode provide a second additional measured EMF providing information with respect to a second of the one or more gases.

24. The gas sensor according to claim 23 , wherein the first of the one or more gases is NO and the second of the one or more gases is NO 2 .

25. The gas sensor according to claim 6 , wherein the first sensing electrode and the second sensing electrode provide the additional measured EMF providing information with respect to a first of the one or more gases and a third sensing electrode and a fourth sensing electrode provide

Assignees

• Blackburn Bryan M
• Wachsman Eric D
• Univ Florida

Inventors

• Blackburn Bryan M
• Wachsman Eric D

Classifications

• Y02A50/20

  Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters · CPC title

• G01N27/4067 Primary

  Means for heating or controlling the temperature of the solid electrolyte · CPC title

• G01N27/4075

  Composition or fabrication of the electrodes and coatings thereon, e.g. catalysts · CPC title

• G01N27/417

  using cells {, i.e. more than one cell} and probes with solid electrolytes · CPC title

• G01N27/419 Primary

  Measuring voltages or currents with a combination of oxygen pumping cells and oxygen concentration cells · CPC title