Zero-standby power hydrogen sensing using event-driven micromechanical switches

Zero-standby power sensors are crucial for enhancing the safety and widespread adoption of hydrogen (H2) technologies in chemical processes and sustainable energy applications, given the flammability of H2 at low concentrations. Here, we report an event-driven hydrogen sensing system utilizing palladium (Pd)-based micromechanical cantilever switches. The detection mechanism relies on strain generation in the Pd layer, which undergoes reversible volume expansion upon hydrogen adsorption. Our experimental and simulation results demonstrate that the bistable micromechanical switch-based sensor generates a wake-up signal with activation time depending on hydrogen concentration in the target environment while always remaining active for events without any standby power consumption under normal conditions. The H2 adsorption-induced subsequent switching of the multi-cantilever-based switch configuration on the sensor resulted in the quasi-quantification of hydrogen concentrations. The reported zero-standby power sensor's operational lifetime is limited by the frequency of detection events and exposure to concentrations exceeding hydrogen's flammability limit. This work advances the development of high-density, maintenance-free sensor networks for large-scale deployment with Internet of Things devices, enabling unattended continuous monitoring of hydrogen generation, transportation, distribution, and end-user applications.