Conductometric butanone gas sensor based on Co3O4 modified SnO2 hollow spheres with ppb-level detection limit

Butanone is a precursor chemical and detrimental to human body, as a consequence, it is significant for social stability to accurately detect trace butanone. In this paper, Co3O4/SnO2 is prepared by modifying Co3O4 nanoparticles on the surface of SnO2 hollow spheres, demonstrating outstanding sensitivity to butanone. SEM, TEM, HRTEM, EDS, XRD, XPS, EPR and BET characterize the morphology, composition, and properties of Co3O4/SnO2. The response of 0.5 at% Co3O4/SnO2 to 100 ppm butanone is 3900 at 210 °C, moreover, the detection limit can reach ppb level (response is 7.2 to 1 ppb), with excellent repeatability and stability. Since Cox+ can replace Sn2+, the content of oxygen vacancy on the surface is adjusted by modifying Co3O4 with different content to improve the gas sensitivity. Of course, the specific surface area and pore size change correspondingly. The role of p-n heterojunction, as well as the synergistic sensitization principle of catalytic and small size effect, are also analyzed in detail. The gas sensing results show that 0.5 at% Co3O4/SnO2 is an excellent gas sensing material.