Effect of calcination temperature on the structure and gas sensing properties of electrospinning ZnO / Co3O4 nanocomposite fibers

ZnO/Co 3 O 4 nanocomposite fibers were synthesized via electrospinning followed by controlled calcination , and their structural evolution and gas sensing performance were systematically investigated. Comprehensive characterization (XRD, SEM, FTIR, XPS) revealed that calcination temperature critically governs crystallinity, oxygen vacancy concentration, and morphology. The results showed that the prepared ZnO/Co 3 O 4 nanocomposite fibers at the 500 °C calcination temperature exhibited a complete morphology and a high concentration of oxygen vacancy (49 %), which promoted oxygen vacancy adsorption and redox reactions, enabling room-temperature operation with a response of 17.56 and a rapid response/recovery time (25/34 s) toward 500 ppm ethylene glycol at room temperature. Mechanistic studies demonstrated that the p-n heterojunction between n-ZnO and p-Co 3 O 4 facilitates interfacial charge transfer, generating built-in electric fields that enhance carrier mobility. This work provides a scalable strategy for designing energy-efficient gas sensors through synergistic optimization of heterojunction engineering and defect chemistry.