Highly aligned SnO2 nanorods on graphene sheets for gas sensors

Highly aligned SnO2 nanorods on graphene 3-D array structures were synthesized by a straightforward nanocrystal-seeds-directing hydrothermal method. The diameter and density of the nanorods grown on the graphene can be easily tuned as required by varying the seeding concentration and temperature. The array structures were used as gas sensors and exhibit improved sensing performances to a series of gases in comparison to that of SnO2 nanorod flowers. For nanorod arrays of optimal diameter and distribution, these structures were proved to exert an enhanced sensitivity to reductive gases (especially H2S), which was twice as high as that obtained using SnO2 nanorod flowers. The improved sensing properties are attributed to the synergism of the large surface area of SnO2 nanorod arrays and the superior electronic characteristics of graphene.