Electrospun ZnO hollow nanofibers gas sensors: An overview

Resistive gas sensors are used widely for the detection of toxic gases. ZnO nanofibers (NFs) with a one-dimensional morphology, high electron mobility, and rough surfaces have abundant adsorption sites for gas molecules. Hence, they are considered reliable materials for sensing toxic gases. Further improvement in their sensing performance can be achieved through the synthesis of hollow ZnO NFs (HNFs), in which their surface areas are significantly higher than ZnO NFs owing to the hollowness of NFs. HNFs are produced mainly by electrospinning, a straightforward and versatile technique with high efficiency. This review paper discusses the gas-sensing properties of pristine, doped, decorated, and composite ZnO HNFs, focusing on the gas-sensing mechanism of ZnO HNFs to provide valuable information on ZnO HNFs for potential use as highly reliable gas sensors. [Display omitted] •Review of ZnO hollow nanofibers (HNFs) for gas sensing studies.•Pristine, doped, decorated and composite ZnO HNF gas sensors are discussed.•Noble metal decoration and composite-based ZnO HNF gas sensors are highly effective.•Explanation of sensing mechanism of different ZnO HNF gas sensors.