▎ 摘　　要

Graphene/SnO2 (G/SnO2) composites were prepared by solvothermal method and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, etc. The effect of the amount of graphene and the solvothermal temperature on the gas sensing properties of G/SnO2 composites was investigated. The results showed that graphene supernatant can regulate the growth of SnO2 crystals. The G/SnO2 nanomaterial obtained with 1 mL supernatant and heat treatment at 160 degrees C for 10 h had good response and selectivity to ammonia at room temperature. The response to 1 000 mu L.L-1 ammonia gas reached 266.4 and the detection limit reached 0.01 mu L.L-1.