Metal Oxide Gas Sensor With Localized Self-Heating for Hydrogen Detection
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Solution Overview
Problem
Existing gas sensing devices require high electricity consumption and elevated temperatures to detect hydrogen gas efficiently, leading to increased power usage and slower sensing speeds at lower temperatures.
Innovation Solution
A gas sensor design featuring a metal oxide gas-sensitive body layer with a local region of higher oxygen deficiency, where the second electrode catalyzes hydrogen atom dissociation, allowing for reduced current usage and faster sensing by concentrating current flow and heating at the local region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gas detecting element is heated to 100°C or more to improve detection sensitivity, then the gas sensing performance is improved, but the electricity consumption increases to about 100 mW
Solution Approach 1:
The patent divides the gas detecting element into multiple local regions with different oxygen deficiency degrees. By segmenting the heating function to only the necessary local region rather than heating the entire element, the electricity consumption is dramatically reduced while maintaining detection sensitivity in the targeted area.
Solution Approach 2:
The patent creates local regions with different oxygen deficiency degrees within the gas detecting element. This local quality variation allows the sensor to achieve high detection sensitivity in specific regions without requiring uniform high-temperature heating across the entire element, thereby reducing overall power consumption.
2Use of energy by moving object
If the gas detecting element operates at low temperature to reduce electricity consumption, then the power usage decreases, but the gas sensing speed becomes slower
Solution Approach 1:
The patent segments the gas detecting element into multiple local regions, with at least one region maintained at higher temperature through localized heating. This allows the sensor to operate overall at low temperature (reducing power consumption) while maintaining fast sensing speed in the heated local region where detection occurs.
Solution Approach 2:
The patent utilizes the resistance change of the gas detecting element itself to generate localized heating through current flow, eliminating the need for external heating devices. The element serves its own heating function, concentrating energy where needed for fast sensing while maintaining low overall power consumption.
3Measurement precision
If a heating heater is installed adjacent to the gas detecting element to maintain temperature, then the detection sensitivity is improved, but the device complexity and power consumption increase
Solution Approach 1:
The patent merges the gas detection function and heating function into a single integrated structure. The gas detecting element itself serves as both the detection medium and the heating element through resistive heating, eliminating the need for separate heating devices and reducing overall device complexity.
Solution Approach 2:
The gas detecting element performs self-heating through the current required for its operation. The electrical current that would otherwise be lost as heat is instead utilized to maintain the necessary temperature for detection, making the system self-sufficient and eliminating external heating components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables hydrogen gas detection with significantly reduced electricity consumption (down to 0.006 mW) and enhanced sensing speed, eliminating the need for separate heating and improving power efficiency and detection reliability.
Implementation Method 1
a gas sensor according to claim 1, wherein the gas-sensitive body layer has a local region in which a degree of oxygen deficiency reversibly changes when gas molecules containing hydrogen atoms are detected, and the resistance of the metal oxide layer decreases when the hydrogen atoms are dissociated from the gas molecules in a part of the second electrode in contact with the local region and the dissociated hydrogen atoms are bound to oxygen atoms in the local region of the metal oxide layer
Implementation Method 2
the second electrode causes catalysis that dissociates the hydrogen atoms from the gas molecules containing the hydrogen atoms
Implementation Method 3
the resistance of the metal oxide layer decreases when the hydrogen atoms are dissociated from the gas molecules in a part of the second electrode in contact with the local region and the dissociated hydrogen atoms are bound to oxygen atoms in the local region of the metal oxide layer
Data Source
Figure 1~2B
Figure 2C~2D
Figure 3~4B
AI summary
A gas sensor (100) includes: a gas-sensitive body layer (103) disposed above a substrate (101) and including a metal oxide layer; a first electrode (104) on the gas-sensitive body layer (103); and a second electrode (105) on the gas-sensitive body layer (103), being apart from the first electrode (104) by a gap (106). The gas-sensitive body layer (103) has a resistance change characteristic that reversibly transitions to a high-resistance state and a low-resistance state on basis of a voltage applied across the first electrode (104) and the second electrode (105). At least a part of the gas-sensitive body layer (103) is exposed to the gap (106). The gas-sensitive body layer (103) has a resistance that decreases when gas containing a hydrogen atom is in contact with the second electrode (105).