Porous single crystal In2O3 beads@TiO2-In2O3 composite nanofibers (TINFs) have been prepared via a facile electrospinning method. The beads were formed because of the existence of hemimicelles in pecursor solution. The formation of hemimicelles was attributed to the synergy of tetrabutyl titanate (TBT) and polyvinylpyrrolidone (PVP). Abundant In(3+) ions were drawn toward the ketonic oxygen of PVP resulting in In(3+) ions aggregation. Compared with pristine In2O3 nanofibers (INFs), the as-prepared TINFs exhibited excellent properties for sensing NO2 gas at room temperature (25 °C). The enhanced sensing property was due to much absorbed oxygen and Schottky junctions between the porous single crystal In2O3 beads and the Au electrode of the sensor. The strategy for combining the unique In2O3 beads@TiO2-In2O3 nanofibers structure which possessed superior conductivity and sufficient electrons with the addition of TiO2 offered an innovation to enhance the gas sensing performance.
Keywords: In2O3 beads; NO2; Schottky contact; TiO2−In2O3 composite nanofibers; gas sensor; porous single crystal.