Isopropanol sensing properties of coral-like ZnO–CdO composites by flash preparation via self-sustained decomposition of metal–organic complexes

The coral-like ZnO–CdO composites with the 3D hierarchical porous structure were prepared in a facile flash from self-sustained decomposition of a metal–organic complex. The phases and the morphologies of the resulting materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectrum (XPS), respectively. The results showed that the ZnCd composites have a coral-like shape with a size of tens of micrometers and exhibit the hierarchically porous morphology, in which the walls of the macropores contain smaller mesopores. The 3D hierarchical architecture consisted of nanoparticles. The gas-sensing characteristics of the resulted porous ZnO–CdO composites for isopropanol were investigated. Indirect-heating sensors using porous ZnO–CdO composites as sensitive materials were fabricated on an alumina tube with Au electrodes and platinum wires. All measurements were performed at several operating temperatures from 175 to 315°C. Good gas-sensing performances to isopropanol have been found for the prepared sample of porous ZnO–CdO composite with a content of 10at% CdO (ZnCd10). It is shown that the sensor exhibits the highest gas response and selectivity at the operating temperature of 248°C, making them promising candidates as practical detectors for isopropanol.