Ambipolarity of large-area Pt-functionalized graphene observed in H2 sensing

A Pt-functionalized graphene (PFG) was prepared, whose hydrogen gas sensing behaviors were studied within the hydrogen concentration range from 1 × 102 to 1 × 104 ppm. The results indicated that resistance of the as-prepared PFG increased with hydrogen at room temperature and 40 °C. On the contrary, the PFG showed decrease in resistance when it interacted with 10,000 ppm of H2 at 65 °C, or with 500 ppm of H2 at 105 °C. A model based on the ambipolarity of graphene was suggested to explain these phenomena.