Characterization and Modeling of a Pt-In₂O₃ Resistive Sensor for Hydrogen Detection at Room Temperature

Sensitive H₂ sensors at low concentrations and room temperature are desired for the early warning and control of hydrogen leakage. In this paper, a resistive sensor based on Pt-doped In₂O₃ nanoparticles was fabricated using inkjet printing process. The H₂ sensing performance of the sensor was evaluated at low concentrations below 1% at room temperature. It exhibited a relative high response of 42.34% to 0.6% H₂. As the relative humidity of 0.5% H₂ decreased from 34% to 23%, the response decreased slightly from 34% to 23%. The sensing principle and the humidity effect were discussed. A dynamic current sensing model for dry H₂ detection was proposed based on Wolkenstein theory and experimentally verified to be able to predict the sensing behavior of the sensor. The H₂ concentration can be calculated within a short measurement time using the model without waiting for the saturation of the response, which significantly reduces the sensing and recovery time of the sensor. The sensor is expected to be a promising candidate for room-temperature H₂ detection, and the proposed model could be very helpful in promoting the application of the sensor for real-time H₂ leakage monitoring.