Low-Cost Hydrogen Sensor in the ppm Range with Purely Optical Readout

Due to the changing global climate, the role of renewable energy sources is of increasing importance. Hydrogen can play an important role as an energy carrier in the transition from fossil fuels. However, to ensure safe operations, a highly reliable and sensitive hydrogen sensor is required for leakage detection. We present a sensor design with purely optical readout that reliably operates between 50 and 100,000 ppm. The building block of the sensor is a reactive sample that consists of a layered structure with palladium nanodisks as the top layer and changes its optical properties depending on the external hydrogen partial pressure. We use a fiber-coupled setup consisting of an LED, a sensor body containing the reactive sample, and a photodiode to probe and read out the reflectance of the sample. This allows separation of the explosive detection area from the operating electronics and thus comes with an inherent protection against hydrogen ignition by electronic malfunctions. Our results prove that this sensor design provides a large detection range, fast response times, and enhanced robustness against aging compared to conventional thin-film technologies. Especially, the simplicity, feasibility, and scalability of the presented approach yield a holistic approach for industrial hydrogen monitoring.