Electrospun Nb-doped CeO2 nanofibers for humidity independent acetone sensing

The humidity causes incorrect signal transmission of gas sensors in real applications. Humidity-independent acetone gas sensors of Nb-doped CeO2 nanofibers were designed and prepared by electrospinning. The 1% Nb-doped CeO2 sensor exhibits excellent response (23.27), good selectivity, repeatability, and long-term stability. This response is 13.37 times higher than that of the undoped CeO2 sensor (1.74) upon exposure to 100 ppm acetone at 240 ?C. The XPS results reveal that the doped Nb element exists as Nb2O5 and can regulate the percentage of Ce3+/Ce4+, thus leading to rich oxygen vacancies and enhanced acetone sensing performance. In addition, the 5% Nb-CeO2 gas sensor exhibits humidity-independent gas sensing. Under humidity conditions, water molecules adsorbed on the active sites of CeO2 will be ionized into H+ as the dominant charged carriers, leading to a large decrease of resistance and enhanced acetone gas sensing; conversely, water molecules chemisorbed on the surface of the doped induced Nb2O5, will induce hydroxyl group, inhibiting acetone gas sensing. Thence, the appropriate Nb dopant can modulate the replacement ratio of H+ to the hydroxyl group, which indicate that proper Nb-doped CeO2 is a promising acetone sensing material in humidity.

Automated summary

In this study, Nb-doped CeO2 nanofibers were prepared to create humidity-independent acetone gas sensors. The doped sensor exhibited excellent response, selectivity, repeatability, and long-term stability due to the presence of rich oxygen vacancies and enhanced acetone sensing performance. The appropriate Nb dopant was able to modulate the replacement ratio of H+ to the hydroxyl group, making it a promising sensing material for acetone in humid conditions.