Hydrogen sensors: palladium-based electrode

Hydrogen sensors are transducer devices and able to convert the hydrogen concentration in the environment to an electrical signal. The detection and monitoring of hydrogen gas under the explosive limit is the essential issue for its applications as the chemical reactant and energy resource. In this study, the sensing mechanism and principle of the palladium-based hydrogen gas sensors are firstly reported. Then, the physical sensing parameter, measuring range, response time and recovery time of the different hydrogen gas sensors are also reviewed. Moreover, the high response speed hydrogen sensors are introduced for practical usages.