Hydrothermally synthesized SnO2-graphene composites for H2 sensing at low operating temperature

The flower-like SnO2 and a series of SnO2-graphene (S–G) composites have been synthesized through a simple one-pot hydrothermal method. The as-prepared products were characterized by XRD, FESEM, TEM, BET, XPS, and Raman spectroscopy. The results clearly revealed that the three-dimensional flower-like SnO2 hierarchical structure was destroyed by graphene nanosheets. The possible growth models for flower-like SnO2 and S–G composites were proposed based on the microstructure characterizations. Furthermore, the H2 sensing responses of all samples were investigated at low operating temperatures (OT) between 30 and 180 °C. The results indicate that the S–G-2-based sensor exhibits the excellent H2 sensing response of 87.2 at a relatively low OT of 150 °C, which is about 70 times higher than that of pure SnO2. Mechanism of H2 sensing of S–G composite has been discussed in terms of resistance change, which is influenced by the Schottky barrier at the interface of S–G composites.