Nanostructured SnO2–ZnO sensors: Highly sensitive and selective to ethanol

Nanostructured SnO2–ZnO as selective ethanol gas sensor materials with controlled grain size and morphology were successfully synthesized by a precipitation method. The structure, morphology, and gas sensing performance of calcined SnO2–ZnO samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and surface area analyzer (using BET method), and a continuous-flow gas sensing measurement system, respectively. The sensors responses depend on the composition, size and morphology of the samples. The sensor with 0.05:1.0 Zn2+:Sn2+ molar ratio was highly sensitive and selective for the detection of ethanol. The gas-sensing mechanism of the nanostructures was discussed. The different reductive–oxidative and acid–base heterostructures of SnO2 and ZnO were suggested as the main reasons for the selective detection of ethanol.