Room-temperature detection of hydrogen by platinum-decorated tin oxide thin films augmented by heat-treatment

We report the room temperature detection of low concentration (few hundred ppm) of hydrogen using sputtered tin oxide (SnO2) thin films catalyzed by ultra-thin layer of platinum (Pt), followed by argon annealing at different temperatures from 150 °C to 600 °C. Structural, morphological, optical, compositional, and gas sensing properties of the fabricated films were investigated. The results show that the gas sensing properties of the heated Pt/SnO2 sensors at room temperature was enhanced as compared to the as-deposited Pt/SnO2, and pristine SnO2 sensors. The maximum response is observed at the post-annealing in the temperature range between 150 and 300 °C. In particular, the sensor annealed at 150 °C, show excellent response, high selectivity, reasonable response and recovery time, as well as high long-term stability for hydrogen detection at room temperature. A plausible mechanism for the observed enhancement in the sensing performance towards hydrogen is proposed.