Extremely Flexible\nMethanol Sensor Based on CNFs/\nNiCo<sub>2</sub>O<sub>4</sub> Nanocomposite

The development of a highly flexible, ultra-selective,\nand stable\ngas sensor is crucial in wearable electronic devices. Herein, carbon\nnanofibers (CNFs)/NiCo<sub>2</sub>O<sub>4</sub> with different nanostructures\nwere prepared and assembled as gas sensors for methanol detection.\nThe CNFs/NiCo<sub>2</sub>O<sub>4</sub> prepared by potassium permanganate\ntreatment showed the highest gas sensitivity (0.1–100 ppm)\nand a good linear response. Meanwhile, the CNF/NiCo<sub>2</sub>O<sub>4</sub> composite membrane sensors were tested after bending at different\nangles of 30°, 60°, and 90°. The response efficiencies\ncould be maintained at 90.8%, 88.7%, and 87.1%, respectively, after\n50 cycles, indicating that the sensors had good stability and flexibility.\nThis approach provides a strategy for the controllable design and\nsynthesis of homogeneous hierarchical CNF/transition metal oxide (TMO)\ncomposites for flexible gas sensor.