Conductometric ozone sensor based on mesoporous ultrafine Co3O4 nanobricks

Monitoring the ozone concentration is widely needed in manufacturing. In this work, mesoporous Co3O4 nanobricks were prepared by a facile hydrothermal corrosion method followed by thermal decomposition from CoSn(OH)(6) precursor. The morphologies, phase, surface composition, nanostructures and exposed crystal facet of the Co3O4 were investigated by using XRD, SEM, TEM, XPS and Raman method. The Co3O4 nanobricks are composed of ultrafine tricobalt tetroxide spinel nanocrystal with size about 10 nm, and the dominant exposed facet is {110}. It is found that those Co3O4 nanobricks show good response to n-butanol and xylene gases, especially to ozone, which reaches the highest response of 130 to 100 ppm ozone at 85 degrees C. In the end, the formation and gas-sensing mechanism of the mesoporous Co3O4 nanobricks were discussed. The good gas sensing properties of the Co3O4 nanobricks can be ascribed to the ultrafine crystallite and mesoporous structure. The high ozone sensitivity can be explained by the {110} exposed facet with Co2+ active sites. Based on the investigate, the Co3O4 nanobricks is proved to be a promising material for ozone sensing.