Synthesis and gas sensing properties of NiO/SnO2 hierarchical structures toward ppb-level acetone detection

We have synthesized pristine SnO2 and NiO/SnO2 hierarchical structures by a facile hydrothermal method. Structural and morphological characterizations of the obtained NiO/SnO2 samples were systematically studied using XRD, SEM, TEM and XPS. Meanwhile, gas-sensing properties of the as-fabricated pristine SnO2 and NiO/SnO2 sensor devices were investigated toward ppb-level acetone detection. The measured results show that the Ni1Sn3 gas sensor can reach a response of 20.18 toward 50 ppm acetone under optimum operating temperature (300 °C), which is about 3.3 times higher than that of pristine sensor. Moreover, the Ni1Sn3 gas sensor also exhibits fast response/recovery time (2 s/9 s), low detection limit (10 ppb) and good selectivity. We attribute the enhanced gas-sensing properties of NiO/SnO2 hierarchical structures to the synergetic effect as well as p-n heterojunction between the NiO and SnO2 structures.