Enhanced gas sensing performance of Co-doped ZnO hierarchical microspheres to 1,2-dichloroethane

A chlorinated compound sensor was developed with cobalt-doped ZnO hierarchical microspheres as the sensing materials, which were prepared by a template-free hydrothermal method via salt basic carbonate precursor combined with subsequent calcination. The calcination of the precursor produces hierarchical microspheres composed of interconnected nanosheets with high porosity resulting from the thermal decomposition process. Field emission scanning electron microscopy (FESEM) reveals that the doped ZnO microspheres have the same microstructure and size as pristine ZnO microspheres. That the dopant Co2+ has substituted Zn2+ sites in ZnO crystal lattice was determined by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV–vis absorption spectrum. These hierarchical cobalt-doped ZnO architectures are highly promising for gas sensor applications. A potential application of Co-doped ZnO microspheres as gas sensors to 1,2-dichloroethane was investigated. It was found that the hierarchical Co-doped ZnO microspheres exhibit dope-induced enhancement of sensing performance with good reversibility and high selectivity. The sensors also show fast response and recovery time of 30 s and 5 s, respectively. It is believed that this precursor route can be extended to fabricate other doped metal oxide nanostructure with enhanced gas sensing performance.