Electrochemical bulk and film-type oxygen sensors: Strategies for detecting extremely low concentration in hydrogen environments
Soon-Won Jung, Min Hyuk Chang, Kyeong-Joon Jo, Mi-Hee Jung, Seung-Yun Lee- Materials Chemistry
- Electrical and Electronic Engineering
- Surfaces, Coatings and Films
- Process Chemistry and Technology
- Instrumentation
- Electronic, Optical and Magnetic Materials
Potentiometric oxygen sensors with excellent sensitivity in a low oxygen concentration range are designed based on intrinsic logarithmic response characteristics, and an asymmetric electrode structure, differentiated from conventional oxygen sensors with reference oxygen gases or parts exposed to air, is implemented. Electrolytes and electrode materials that formulate oxygen sensor devices are evaluated by comprehensively considering their reactivity to trace oxygen, oxygen ion formation, and ease of movement. The sensor using an yttria-stabilized zirconia bulk ceramic electrolyte measures the oxygen concentration in an oxygen-hydrogen mixture down to 0.5%, with a response time of 7.8 s. The sensor with a Nafion proton conductor film and a polyimide gas separation membrane allows room-temperature sensing and measures the oxygen concentration to a minimum of 2%.