Fabrication and gas-sensing performance of nanorod-assembled SnO2 nanostructures

The manner how nano building blocks assemble into hierarchical architectures exerts a tremendous influence on gas-sensing property of the metal oxides. Herein, we focus on tuning the 1D SnO2 rectangular nanorods into 3D hierarchical nanoflowers by manipulating the concentration of surfactant (citric acid) as well as the period of hydrothermal process, and then investigate their gas-sensing performance. Nanostructures assembled by short, unordered and well-ordered rectangular nanorods were successfully fabricated, corresponding to infant, abnormal and blooming SnO2 nanoflowers, respectively. In comparison, sensor based on blooming SnO2 nanoflowers exhibited significantly enhanced gas response to ethanol than the other two, not only in terms of the sensitivity but also the response/recovery time, which may be mainly attributed to the sufficient diffusion channel and exposed surface provided by finely dispersed nanorods in the blooming nanoflowers.