Designed Synthesis of In₂O₃ Beads@TiO₂–In₂O₃ Composite Nanofibers for High Performance NO₂ Sensor at Room Temperature

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 In³⁺ ions were drawn toward the ketonic oxygen of PVP resulting in In³⁺ 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.