Gas sensors based on Co3O4/TiO2 core-shell nanofibers prepared by coaxial electrospinning for breath marker acetone detection

Gas sensors play an important role in environmental detection and exhaled breath biomarker detection. In this paper, Co 3 O 4 /TiO 2 core-shell NFs were synthesized by coaxial electrostatic spinning method. The morphology, structure and composition of the composites were analyzed by SEM, TEM, EDS , XRD and XPS . The results of conventional static gas sensitivity performance tests showed that the Co 3 O 4 /TiO 2 sensors exhibited a P-type response with excellent sensing performance to acetone. The higher response values and better selectivity of Co 3 O 4 /TiO 2 sensors for acetone were observed compared to Co 3 O 4 NFS and TiO 2 NFS sensors, and the shortcomings that cannot be recovered from TiO 2 NFS have also been significantly improved. In addition, the breath simulation experiments showed that the Co 3 O 4 /TiO 2 sensors have a lower acetone detection limit down to 500 ppb. The initial resistance of the Co 3 O 4 /TiO 2 sensor does not change significantly with relative humidity increasing, and the response value fluctuates by 1.5% at 300 °C. The enhanced acetone sensing performance of Co 3 O 4 /TiO 2 is ascribed to the heterojunction and porous structure which result in more adsorbed active sites on the material surface. With the advantages of low detection limit and high anti-humidity, Co 3 O 4 /TiO 2 gas sensors are expected to become a potential candidate for the detection of acetone in exhaled gas of patients with diabetes in clinical non-invasive testing.