Ammonia Gas Sensor Using Composite Oxide Electrode
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Solution Overview
Problem
Current ammonia sensors lack high sensitivity and selectivity, particularly in industrial settings where accurate ammonia monitoring is crucial for pollution control and urea-based catalyst efficiency, and there is a need for a reliable, economically-produced ammonia sensor for various applications.
Innovation Solution
An ammonia gas sensor comprising an electrolyte with a reference electrode and an ammonia selective sensing electrode made of an oxide material characterized by the formula AxMyOz, where M is vanadium, tungsten, or molybdenum, and A is specific metals, using yttria-stabilized zirconia as the electrolyte to enable electrochemical hydrogen ion transfer, with dopants for stability and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ammonia sensors are used, then the sensor can detect ammonia presence, but the sensitivity and selectivity are insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the sensing electrode by using oxide materials with specific formulas (AxMyOz) containing vanadium, tungsten, or molybdenum combined with other metals, and adjusts operating temperature parameters to achieve high sensitivity and selectivity for ammonia detection while maintaining reliability
Solution Approach 2:
The patent employs composite oxide materials as the sensing electrode, combining multiple metal elements (M from vanadium, tungsten, or molybdenum group with metals from group A) to create a material with superior ammonia detection characteristics that single materials cannot achieve
2Measurement precision
If the sensor operates at higher temperatures to improve response, then sensitivity increases, but the stability of the sensor material deteriorates
Solution Approach 1:
The patent optimizes the chemical composition parameters of the oxide material (formula AxMyOz with specific metal combinations) to achieve a balance where the material remains stable at elevated operating temperatures while maintaining high ammonia detection sensitivity
Solution Approach 2:
The patent uses yttria-stabilized zirconia as the electrolyte, which is a well-established stable material that can withstand high temperatures, effectively acting as a stable foundation for the sensor structure
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
The sensor provides accurate ammonia concentration measurement with high selectivity and sensitivity, resisting interference from NOx, CO, and HC, and maintaining reliability over a wide temperature range, enabling effective pollution control and efficient catalyst regeneration.
Implementation Method 1
The electrolyte is composed of a material capable of electrochemical transfer of hydrogen ions
Implementation Method 2
The ammonia selective sensing electrode is composed of an oxide material characterized by the formula AxMyOz
Data Source
AI summary
One embodiment of an ammonia gas sensor includes: a reference electrode, an ammonia selective sensing electrode and an electrolyte disposed therebetween. The sensing electrode comprises the reaction product of a main material selected from the group consisting of vanadium, tungsten, molybdenum, vanadium oxides, tungsten oxides, molybdenum oxides, and combinations comprising at least one of the foregoing main materials, and an electrically conducting material selected from the group consisting of electrically conductive metals, electrically conductive metal oxides, and combinations comprising at least one of the foregoing.