The synthesis of hierarchically porous nanostructures is always highly concerned by researchers. Herein, we report a simple, low-cost and green approach to obtain hierarchical ZnSnO3 porous nanostructures by using the branches of pterocarya stenoptera, catalpa and apricot as biotemplate, respectively. The gas sensing properties of hierarchical ZnSnO3 porous nanostructures are systematically analyzed. The results exhibit that the ZnSnO3 based gas sensors show not only high responses and rapid response/recovery speed (2/8 s for ZnSnO3-1, 1/10 s for ZnSnO3-2 and 2/20 s for ZnSnO3-3) at the working temperature of 240oC but also excellent anti-humidity properties, gas selectivity, repeatability and long-term stability. Besides, the linear relationship between the responses and the formaldehyde concentration (1–200 ppm) is observed. The excellent gas sensing performance of the ZnSnO3 based gas sensors is mainly ascribed to the unique structural merits. The simple synthetic method in this paper also provides implications for the design and synthesis of porous MOSs.
