Excellent acetone sensor of La-doped ZnO nanofibers with unique bead-like structures

• La-doped ZnO nanofibers with unique bead-like structures were facilely produced.
• The 1.0 wt% La-doped ZnO sensor has the highest selectivity and response.
• Increased adsorption capacity of O contributes to the markedly increased response.
• The catalytic activity of La2O3, etc. contributes to the increased acetone response.

In this work, Lanthanum (La) doped ZnO nanofibers with bead-like structures were facilely produced by electrospinning technique. The obtained La-doped ZnO products were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller method, transmission electron microscopy and X-ray photoelectron spectroscopy (XPS). The results show that La doping changes the structures of ZnO nanofibers markedly. La-doped ZnO nanofibers have unique bead-like nanostructures, in which two phases of hexagonal La2O3 and wurtzite ZnO coexist along with partially incorporation of La into ZnO lattice. The gas sensing performances of the La-doped ZnO nanostructures to acetone were investigated via static gas sensor testing system. The sensing test results indicate that an appropriate amount of La doping greatly improves the gas sensing properties of ZnO nanofibers. The 1.0 wt% La-doped ZnO sensor has the highest selectivity and response (64, to 200 ppm acetone at 340 °C), in addition to its short response time and recovery time. The unique bead-like structure and the gas sensing mechanism of La-doped ZnO nanofibers are discussed. The La-doped ZnO nanostructures we have produced can be used as a promising material for acetone sensors.