Construction of Electrospun ZnO-NiO Nanofibers for Enhanced Ethanol Gas Sensing

Semiconducting metal oxides with nanofiber (NF) morphologies are among the most promising materials for the realization of gas sensors. In this study, we have prepared electrospun ZnO-NiO composite NFs with different amounts of NiO (0, 20, 40, 60 and 80% wt%) for the systematic study of ethanol gas sensing. The fabricated composite NFs were annealed at 600 °C for crystallization. Based on characterization studies, NFs were produced with desired morphologies, phases, and chemical compositions. Ethanol gas sensing studies revealed that the sensor with 40 wt% NiO had the highest response (3.6 to 10 ppm ethanol) at 300 °C among all gas sensors. The enhanced gas response was ascribed to the formation of sufficient amounts of p-n NiO-ZnO heterojunctions, NFs' high surface areas due to their one-dimensional morphologies, and acid-base interactions between ZnO and ethanol. This research highlights the need for the optimization of ZnO-NiO composite NFs so that they achieve the highest sensing response, which can be extended to other similar metal oxides.