Room temperature agricultural ethylene detection by freestanding three-dimensional porous-ZnO/carbon nanofibers

Ethylene is one of the important indicators to reflect the ripeness and senescence of the fruit. Ethylene sensor can be applied for fast ethylene detection nondestructively, yet high temperature condition of the common metal oxide semiconductors restrains its agricultural applications. Herein, porous-ZnO/carbon nanofibers (CNFs) three-dimensional structure, derived from Zeolite imidazole framework-8 (ZIF-8) /polyacrylonitrile (PAN) electrospun nanofibers, was proposed and further optimized. The results showed that porous-ZnO/CNFs exhibited increasing resistance to reducing ethylene at room temperature , well explained by the Fermi levels’ relative position of the sensing system. Repeatability, selectivity and stability were demonstrated. The addition of porous-ZnO (10 % composting mass ratio) resulted in a 428 % increase in the ethylene-sensing response compared with CNFs, and a 64.2 % improvement compared with ZnO/CNFs. The outstanding sensing performance can be attributed to the synergistic effect of porous and interconnected morphology, the formed p-n heterojunction , as well as oxygen-vacancy effect. This strategy is beneficial for designing efficient gas sensors at room temperature, and exploring the application of the advanced gas sensors in intelligent agriculture field.