Synthesis of porous NiO-In2O3 composite nanofibers by electrospinning and their highly enhanced gas sensing properties

Pure In2O3 and NiO-In2O3 composite nanofibers with different molar ratio (Ni/In = 2.5%, 5% and 7.5 mol%) were fabricated by the electrospinning and calcination method. The gas sensing properties of ethanol based on the produced nanofibers were investigated. The results revealed that all of the composite nanofibers were demonstrated with higher sensing performance as compared with the pure In2O3 nanofibers. Particularly, the sensor constructed by 5 mol% composite nanofibers displayed the highest response, showing an excellent response value of 78 under 100 ppm ethanol at 300 °C. Additionally, the sensor fabricated by 5 mol% NiO-In2O3 composite nanofibers also exhibited good selectivity and stability to ethanol. From our perspective, the improved sensing performance can mainly be attributed to the formation of p-n junctions between NiO and In2O3, high capability of absorbed oxygen species and increased BET specific surface areas of the 5 mol% NiO-In2O3 composite nanofibers.