Hydrogen Selective Gas Sensor Based on Attenuation Measurement of Acoustic Wave Using Uncoated CMUT

The present work demonstrates the possibility of using capacitive micromachined ultrasonic transducers as a selective hydrogen gas sensor without functionalized coating. The sensor principle is based on the attenuation measurement of ultrasonic acoustic wave in gas. Measurements of selectivity with respect to methane and carbon dioxide are presented and a limit of detection of 0.05% of hydrogen in nitrogen is demonstrated experimentally. Such sensors can be used for safety monitoring of hydrogen production plants, storage tanks, radioactive waste management, refueling stations and automotive vehicles.