Voltage-dependent gas discrimination using self-activated graphene with Pt decoration

Gas discrimination using a chemoresistive sensor without heater is still a challenging research topic. Designing sensor arrays composed of various types of individual sensors have been considered as a general strategy to obtain abundant data for the classification. However, fabrication process and integration of various sensors on a small substrate are complex and challenging. Here, we report voltage-dependent gas discrimination using a single sensor with varied sensing properties induced by different levels of self-activation. The sensor can be employed for a hydrogen sensor with an ultralow detection limit down to 0.219 ppt, owing to the catalytic effect of the Pt nanoparticles. In addition, abundant data can be accumulated from the single sensor using different self activation states. The switching time of about 2 s for each activation state enables fast data acquisition for principal component analysis. This work is not only a proof-of-concept study for gas discrimination using a single sensor, but also broadens potential of graphene gas sensors decorated with noble metal nanoparticles for practical applications.