Facile Fabrication of Mesoporous Hierarchical Co-Doped ZnO for Highly Sensitive Ethanol Detection

The development of highly sensitive gas-sensing materials for the detection of volatile organic compounds at low temperature is vital for gas sensors. Herein, novel mesoporous hierarchical Co-doped ZnO was successfully constructed by calcining layered zinc hydroxide precursors prepared through a facile hydrothermal route. The hierarchical architectures of the precursors were preserved after their conversion to mesoporous Co-doped ZnO through calcination, and the obtained mesoporous hierarchical Co-doped ZnO was systematically characterized by X-ray powder diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, nitrogen adsorption desorption analysis, and X-ray photoelectron spectra. The hierarchical Co-doped ZnO was assembled by many thin nanosheets composed of small nanoparticles (8.6 nm), and the hierarchical Co-doped ZnO with 5 atom % doping amount has a specific surface area of 111.7 m(2) g(-1) and abundant mesopores in the range of 2-50 nm. Gas-sensing tests demonstrate that the hierarchical 5 atom % Co-doped ZnO showed a sensing response of 54 to 50 ppm ethanol at the low operating temperature of 180 degrees C, and the response followed a good linear relationship with 5-160 ppm ethanol. Moreover, the hierarchical Co-doped ZnO also exhibited distinctive selectivity, good response repeatability, and preferable long-term stability to ethanol, indicating that the nanosheet-assembled mesoporous hierarchical Co-doped ZnO has potential applications in high-performance gas sensing materials working at low temperature.