High sensitivity and surface mechanism of MOFs-derived metal oxide Co3O4-SnO2 hollow spheres to ethanol

Metal-organic Frameworks (MOFs) have been widely studied due to their high porosity and large surface area. In this paper, Co3O4-modified SnO2 hollow spheres with excellent ethanol gas sensitivity were prepared by using ZIF-67 as template by two-step hydrothermal pyrolysis at 300 °C. The elemental composition, morphology, structure and gas sensitivity properties of the materials were characterized by XRD, SEM and gas-sensitive analysis system. The experiment shows that the ZIF-67-derived Co3O4-SnO2 composite has a response value of 33.9 to 100 ppm ethanol gas at the optimum operating temperature of 225 °C, which is significantly higher than that of pure SnO2. According to the characteristics of gas sensitivity and morphology, the enhancement of gas sensitivity is due to the increase of oxygen vacancies, which promotes oxygen adsorption and surface chemical reaction.